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CONTENTS KANDUNGAN
1
THE STRUCTURE OF ATOMS STRUKTUR ATOM
2
CHEMICAL FORMULA AND EQUATIONS FORMULA DAN PERSAMAAN KIMIA
22
3
PERIODIC TABLE JADUAL BERKALA
49
4
CHEMICAL BOND IKATAN KIMIA
72
5
ELECTROCHEMISTRY ELEKTROKIMIA
88
6
ACID AND BASES ASID DAN BES
114
7
SALT GARAM
139
8
MANUFACTURED SUBSTANCES IN INDUSTRY BAHAN KIMIA DALAM INDUSTRI
168
Con-Chem F4 (B).indd 3
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Chemistry Form 4 • MODULE
1
THE STRUCTURE OF ATOMS STRUKTUR ATOM MATTER / JIRIM
• PARTICLE THEORY OF MATTER / TEORI ZARAH JIRIM – To state the particle theory of matter Menyatakan teori zarah jirim
– To differentiate and draw the three types of particles i.e. atom, ion and molecule Membezakan dan melukis tiga jenis zarah jirim iaitu atom, ion dan molekul
– To describe the laboratory activity to investigate the diffusion of particles in gas, a liquid and a solid. (To prove that matter is made up of tiny and discrete particles) Menghuraikan aktiviti makmal untuk mengkaji resapan zarah dalam gas, cecair dan pepejal (Untuk membuktikan bahawa jirim terdiri daripada zarah-zarah yang halus dan diskrit)
• KINETIC THEORY OF MATTER / TEORI KINETIK JIRIM – To state the kinetic theory of matter Menyatakan teori kinetik jirim
– To relate the change of physical states of matters with energy change Menghubungkaitkan perubahan keadaan jirim dengan perubahan tenaga
– To relate the change of energy in the particles with kinetic particle theory of matter Menghubungkaitkan perubahan tenaga dalam zarah dengan perubahan tenaga kinetik zarah
THE STRUCTURE OF ATOMS / STRUKTUR ATOM
• HISTORY OF ATOMIC MODELS DEVELOPMENT / SEJARAH PERKEMBANGAN MODEL ATOM
– To state the contribution of scientists in the atomic structure model such as the scientists who discovered electron, proton, nucleus, neutron and shell Menyatakan sumbangan ahli sains kepada perkembangan model struktur atom dan ahli sains yang menemui elektron, proton, nukleus, neutron dan petala
• SUBATOMIC PARTICLES / ZARAH-ZARAH SUBATOM
– To compare and differentiate subatomic particles i.e. proton, neutron and electron from the aspect of charge, relative mass and location Membanding dan membezakan zarah-zarah subatom iaitu proton, neutron dan elektron dari segi cas, jisim relatif dan kedudukan
– To state the meaning of proton number and nucleon number based on the subatomic particle Menyatakan maksud nombor proton dan nombor nukleon berdasarkan zarah subatom
– To write the symbol of elements with proton number and nucleon number Menulis simbol unsur yang mengandungi nombor proton dan nombor nukleon
• ISOTOPE / ISOTOP
– To state the meaning, examples and the use of isotopes Menyatakan maksud isotop, contoh-contoh isotop dan kegunaan isotop
• ELECTRON ARRANGEMENT / SUSUNAN ELEKTRON
– To know the number of electron shells and number of electrons in the 1st, 2nd and 3rd shell Mengetahui bilangan petala elektron serta bilangan elektron yang diisi dalam petala 1, 2 dan 3
– To write the electron arrangement of atoms based on proton number or number of electrons and state the number of valence electron
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Menulis susunan elektron bagi suatu atom berdasarkan nombor proton atau bilangan elektron dan seterusnya menyatakan bilangan elektron valens
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MODULE • Chemistry Form 4
MATTER / JIRIM
Matter is any substance that has mass and occupies space. Jirim adalah sebarang bahan yang mempunyai jisim dan memenuhi ruang. The Particle Theory of Matter / Teori Zarah Jirim
Matter is made up of tiny and discrete particles. Three types of tiny particles are atoms ,
1
atom
Jisim terdiri daripada zarah yang halus dan diskrit. Tiga jenis zarah tersebut ialah
,
ions
ion
and molecules . molekul .
dan
Matter can be classified as element or compound. / Jirim boleh dikelaskan sebagai unsur atau sebatian. Complete the following: / Lengkapkan yang berikut:
2 3
MATTER / JIRIM ELEMENT / UNSUR satu type of atom. A substance made from only satu Bahan yang terdiri daripada jenis atom sahaja.
COMPOUND / SEBATIAN two or more A substance made from elements which are bonded together. dua Bahan yang terdiri daripada
atau
different
lebih
unsur berbeza yang terikat secara kimia.
Types of particles / Jenis zarah
Atom / Atom The smallest neutral particle of an element (Normally pure metals, noble gases and a few non-metal elements such as carbon and silicon). Zarah neutral yang paling kecil bagi suatu unsur (Biasanya logam tulen, gas adi dan beberapa unsur bukan logam seperti karbon dan silikon).
Example:
Types of particles / Jenis zarah
Molecule / Molekul A neutral particle consists of similar non-metal atoms which are covalently-bonded.
Molecule / Molekul A neutral particle consists of different non-metal atoms which are covalently-bonded.
Zarah neutral terdiri daripada atom-atom bukan logam serupa terikat secara ikatan kovalen.
Zarah neutral terdiri daripada atom-atom bukan logam berlainan terikat secara ikatan kovalen.
Example:
Example:
Contoh:
Contoh:
Oxygen gas, O2
Carbon dioxide gas, CO2
Gas oksigen, O2
Gas karbon dioksida, CO2
Contoh:
Sodium metal, Na
O O
Logam natrium, Na
O O
Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na
O O
O
C
O
O
C
O
Ne
O
Example: Contoh:
Na+ Cl – Na+ Cl – Na+
Air, H2O
H H H H
Natrium klorida, NaCl
Water, H2O
Gas hidrogen, H2
H H
Ne
C
Zarah bercas positif atau negatif terbentuk dari logam dan bukan logam terikat secara ikatan ion. Daya tarikan antara dua ion yang berlawanan cas membentuk ikatan ion.
Sodium chloride, NaCl Hydrogen gas, H2
Neon gas, Ne Gas Neon, Ne
O
Ion / Ion Positively or negatively charged particles, which are formed from metal atom and non-metal atom respectively. The force of attraction between the two oppositely charged ions forms an ionic bond.
H H
O O
Cl – Na+ Cl – Na + Cl –
H H
O
H
H
Ne
Na+ Cl – Na+ Cl – Na+
Calcium oxide, CaO Kalsium oksida, CaO
Ca2+ O 2– Ca2+ O 2– Ca2+ O 2– Ca2+ O 2– Ca2+ O 2– Ca2+ O 2– Ca2+ O 2– Ca2+
– Elements can be identified as metal or non-metal by referring to the Periodic Table. Unsur boleh dikenal pasti sebagai logam atau bukan logam dengan merujuk kepada Jadual Berkala Unsur.
– Formation of molecule and ion will be studied in Chapter 4 (Chemical Bond). Publica
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Chemistry Form 4 • MODULE
4
Determine the type of particles in the following substances: Tentukan jenis zarah bagi setiap bahan berikut: Substances
Type of particle
Substances
Type of particle
Substances
Type of particle
Molecule
Sulphur dioxide (SO2) Sulfur dioksida (SO2)
Molecule
Tetrachloromethane (CCl4) Tetraklorometana (CCl4)
Molecule
Copper(II) sulphate (CuSO4) Kuprum(II) sulfat (CuSO4 )
Ion
Iron (Fe) Ferum (Fe)
Atom
Zink chloride (ZnCl2) Zink klorida (ZnCl2 )
Ion
Argon (Ar) Argon (Ar)
Atom
Carbon (C) Karbon (C)
Atom
Hydrogen peroxide (H2O2) Hidrogen peroksida (H2O2)
Molecule
Bahan
Jenis zarah
Hydrogen gas (H2) Gas hidrogen (H2)
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Bahan
Jenis zarah
Bahan
Jenis zarah
Diffusion Resapan
(a) The tiny and discrete particles that made up matter are constantly moving. In gases, these particles are very far apart from each other, in liquids, the particles are closer together and in solids, they are arranged closely packed. Jirim terdiri daripada zarah-zarah halus dan diskrit yang sentiasa bergerak. Dalam gas, susunan zarah-zarahnya adalah berjauhan antara satu sama lain, dalam cecair, zarah-zarahnya disusun lebih rapat dan dalam pepejal, zarah-zarahnya disusun dengan sangat padat dan teratur.
(b) Diffusion occurs when particles of a substance move between the particles of another substance. Resapan berlaku apabila zarah-zarah suatu bahan bergerak di antara zarah-zarah bahan lain.
(c) Diffusion occurs in a solid, liquid and gas. Complete the following table: Resapan berlaku dalam pepejal, cecair dan gas. Lengkapkan jadual berikut: Diffusion in a gas Resapan dalam gas
Experiment Eksperimen
A few drops of bromine liquid Beberapa titis cecair bromin
After few minutes Selepas beberapa minit
Diffusion in a liquid Resapan dalam cecair
Water Air
After a few hours Selepas beberapa jam
Potassium manganate(VII) Kalium manganat(VII)
Observation Pemerhatian
Explanation Penerangan
The brown colour of bromine vapour, far Br2 spreads throughout the two jars.
The purple colour of solid potassium manganate(VII), KMnO4 spreads slowly throughout the water.
Diffusion in a solid Resapan dalam pepejal
Gel
Agar-agar
Copper(II) sulphate
After a day Selepas sehari
Kuprum(II) sulfat
The blue colour of copper(II) sulphate, CuSO4 spreads very slowly throughout the gel.
Warna perang wap bromin, Br2 merebak cepat memenuhi kedua-dua dengan balang gas.
Warna ungu pepejal kalium manganat(VII), perlahan KMnO4 merebak dengan di dalam air.
Bromine vapour, Br2 and air are made up of molecules . Wap bromin, Br2 dan udara terdiri molekul daripada . molecules diffuse Bromine quickly between large
Potassium manganate(VII) is Copper(II) sulphate, CuSO4 is made made up of potassium ions and up of copper(II) ions and manganate(VII) ions. The ions sulphate ions . The ions diffuse slowly between close diffuse very slow between space of water particles which is in closely packed space of gel particles liquid form. which is in solid form.
space of air particles which is in gas form.
Kuprum(II) sulfat, CuSO4 terdiri daripada ion ion kuprum(II) dan Ion-ion sulfat. ini meresap dengan perlahan sangat antara ruang padat zarah agar-agar yang berbentuk pepejal. n io
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Molekul bromin meresap pantas besar melalui ruang antara zarahzarah udara yang berbentuk gas.
Kalium manganat(VII) terdiri daripada ion kalium dan ion manganat(VII). Ion-ion perlahan ini meresap rapat antara ruang zarah air yang berbentuk cecair.
Warna biru kuprum(II) sulfat, sangat perlahan CuSO4 merebak di dalam agar-agar.
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MODULE • Chemistry Form 4
(d) Conclusions: Kesimpulan:
gas than in liquid. There is (i) Diffusion occurs faster in gas gas a than a liquid. Particles in a are closer are together.
larger
space in between the particles of
further
apart. The particles in the liquid
gas Resapan berlaku lebih cepat di dalam berbanding di dalam cecair. Terdapat ruang yang gas gas berbanding dengan cecair. Zarah-zarah adalah antara zarah-zarah lebih rapat antara satu sama lain. antara satu sama lain. Zarah-zarah cecair adalah
liquid than in solid. There is (ii) Diffusion occurs faster in a liquid of a than a solid. The particles in the solid are very cecair
Resapan berlaku lebih cepat di dalam cecair antara zarah-zarah dan
padat
larger
lebih besar berjauhan
space in between the particles
close
together. lebih besar
berbanding di dalam pepejal. Terdapat ruang yang
rapat
berbanding dengan pepejal. Zarah-zarah pepejal tersusun sangat
antara satu sama lain.
(iii) Bromine gas, potassium manganate(VII) and copper(II) sulphate are made up of particles that are constantly moving/constant motion .
tiny
and
halus
Gas bromin, kalium manganat(VII) dan kuprum(II) sulfat terdiri daripada zarah-zarah sentiasa bergerak . yang
discrete
diskrit
dan
The Kinetic Theory of Matter / Teori Kinetik Jirim
solid
Matter exists in three different states which are
1
pepejal
Jirim wujud dalam tiga keadaan iaitu
Matter that made up of
2
tiny
Jirim terdiri daripada zarah-zarah
and halus
As the temperature increases, the
3
Apabila suhu meningkat, tenaga
,
discrete
kinetic
kinetik
,
cecair
liquid
and
gas
gas
.
dan
. moving
particles which are always in constantly
dan
diskrit
yang sentiasa
bergerak
.
.
energy of particles increases and the particles move
zarah-zarah akan bertambah dan zarah-zarah akan bergerak dengan
faster
.
lebih cepat
.
Particles in different states of matter have different arrangement, strength of forces between them, movement and energy content.
4
Zarah-zarah
dalam keadaan jirim yang berbeza mempunyai susunan, daya tarikan antara zarah, pergerakan dan kandungan
tenaga yang berbeza.
Complete the following table: / Lengkapkan jadual di bawah:
5
State of matter
Solid
Keadaan jirim
Liquid
Pepejal
Gas
Cecair
Gas
Draw the particles arrangement. Each particle (atom/ ion/ molecule) is represented by Lukis susunan zarah. Setiap zarah (atom / ion / molekul) diwakili dengan ‘ ’
Particles arrangement Susunan zarah
The particles are arranged closely packed in orderly
manner.
Zarah-zarah tersusun teratur dan .
Particles movement
m
orderly manner padat
.
Zarah-zarah tersusun tidak teratur tetapi
fixed position.
throughout the liquid.
Zarah bergetar dan berputar pada kedudukan tetap.
terpisah jauh Zarah-zarah antara satu sama lain.
.
Particles can vibrate , rotate and move
from
each other.
padat
Particles can only vibrate and rotate about their
The particles are very widely separated
Zarah bergetar , berputar dan bergerak dalam cecair.
Particles can vibrate , rotate and move
freely.
Zarah bergetar , berputar dan bergerak bebas.
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Pergerakan zarah
The particles are arranged closely packed but not in
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Chemistry Form 4 • MODULE
Strong
Attractive forces between the particles Daya tarikan antara zarah
forces between the particles but weaker than
Very strong forces between the particles.
the forces in the solid.
Daya tarikan yang sangat kuat antara zarah-zarah.
kuat Daya tarikan yang antara zarah-zarah tetapi lebih lemah berbanding di
Weak
forces between
the perticles lemah
Daya tarikan yang antara zarah-zarah.
dalam pepejal.
Energy content of the particles Kandungan tenaga zarah
6
Energy content is very low . Kandungan tenaga sangat rendah .
Energy content is higher than solid but less than in a gas. Kandungan tenaga lebih tinggi daripada pepejal tetapi lebih rendah daripada gas.
very
Energy content is high. Kandungan tenaga tinggi.
sangat
Changes in the state of matter Perubahan keadaan jirim
(a) Matter undergoes change of state when
heat
energy is absorbed or haba
Jirim mengalami perubahan keadaan apabila tenaga
serap
di
(i) When heat energy is absorbed by the matter (it is heated), the increases and they vibrate faster. diserap Apabila tenaga haba oleh jirim (semasa dipanaskan), tenaga dan zarah tersebut bergerak dengan lebih cepat.
(ii) When matter releases heat energy (it is cooled), the they vibrate less vigorously. dibebaskan Apabila tenaga haba zarah tersebut bergerak kurang cergas.
kinetic
released/lose atau di
kinetic
:
bebaskan
:
energy of the particles
kinetik
zarah
bertambah
energy of the particles decreases and
oleh jirim (semasa disejukkan), tenaga kinetik zarah
berkurang
dan
(b) Inter - conversion of the states of matter: Perubahan keadaan jirim: Solid Pepejal 7
Melting / Peleburan Freezing / Pembekuan
Liquid Cecair
Boiling/Evoporation / Pendidihan/Penyejatan Condensation / Kondensasi
Gas Gas
Determination of melting and freezing points of naphthalene Penentuan takat lebur dan takat beku naftalena
Materials / Bahan: Naphthalene powder, water Apparatus / Radas: Boiling tube, conical flask, beaker, retort stand, thermometer 0 – 100°C, stopwatch, Bunsen burner and wire gauze Procedure / Prosedur: I. Heating of naphthalene / Pemanasan naftalena Set-up of apparatus: / Susunan radas: Thermometer / Termometer Boiling tube / Tabung didih Water / Air Naphthalene / Naftalena
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MODULE • Chemistry Form 4
(a) A boiling tube placed into it. Tabung didih
3 - 5 cm
is filled
height with naphthalene powder and a 3 – 5 cm
diisi dengan serbuk naftalena setinggi
dan
thermometer
termometer
is
diletakkan
di dalamnya.
(b) The boiling tube is immersed in a water bath as shown in the diagram so that the water level in the water bath is higher than naphtalene powder in the boiling tube. Tabung didih dimasukkan ke dalam kukus air seperti di dalam gambar rajah dan pastikan aras air dalam kukus air lebih tinggi daripada aras naftalena dalam tabung didih.
(c) The water is
heated
Air dipanaskan dan naftalena
and the naphthalene is dikacau
stirred
perlahan-lahan dengan
slowly with termometer
thermometer
.
.
60°C , the stopwatch is started. The temperature of (d) When the temperature of naphthalene reaches 90°C naphthalene is recorded at 30 seconds intervals until the temperature of naphthalene reaches . 60°C
Apabila suhu naftalena mencapai 90°C
sehingga suhunya mencapai
II.
, mulakan jam randik. Suhu naftalena dicatat setiap
30 saat
.
Cooling of naphthalene / Penyejukan naftalena
Naphthalene Naftalena
(a) The boiling tube and its content is removed from the water bath and put into a in the diagram.
conical flask kelalang kon
Tabung didih dan kandungannya dikeluarkan daripada kukus air dan dipindahkan ke dalam dalam gambar rajah.
as shown seperti
stirred constantly with thermometer throughout cooling (b) The content in the boiling tube is supercooling process to avoid (the temperature of cooling liquid drops below freezing point, without the appearance of a solid). dikacau Kandungan dalam tabung didih perlahan-lahan dengan termometer sepanjang proses penyejukan untuk penyejukan lampau (Suhu cecair yang disejukkan turun melepasi takat beku tanpa pembentukan mengelakkan pepejal).
(c) The temperature of naphthalene is recorded every 60°C to . Suhu naftalena dicatat setiap
30 saat
30 seconds
sehingga suhunya mencapai
interval until the temperature drops 60°C
.
(d) A graph of temperature against time is plotted for the heating and cooling process respectively.
m
suhu
melawan
masa
dilukis untuk proses pemanasan dan penyejukan.
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Chemistry Form 4 • MODULE
The Explanation of the Heating Process of Matter / Penerangan Proses Pemanasan 1
The heating curve of naphthalene: Lengkung pemanasan naftalena: Temperature/°C Suhu/°C
F D B
E
C
A Time/s Masa/s
2
faster
When a solid is heated, the particles absorb heat and move absorbed energy is , the state of matter will change.
as its energy content increases. As the heat
lebih cepat Apabila pepejal dipanaskan, zarah-zarah menyerap haba dan bergerak diserap menyebabkan perubahan keadaan jirim. Tenaga haba
Point Titik
A to B A ke B
State of Matter
Explanation
Keadaan jirim
Penerangan
absorbed
Heat energy is kinetic
Solid
energy to diserap
pepejal
oleh zarah-zarah
lebih cepat
dan zarah bergetar dengan
absorbed
Heat energy
Solid and Liquid
solid
by the particles in the increase and vibrate
naphthalene causing their
faster
. The temperature
increases. Tenaga haba bertambah
B to C B ke C
disebabkan kandungan tenaga bertambah.
overcome
naftalena menyebabkan tenaga meningkat . Suhu semakin
by the particles in the
forces between particles so that the remains constant
temperature
diserap
Tenaga haba yang
liquid solid
C to D C ke D
Liquid
Tenaga haba bertambah
turn to
pepejal oleh zarah-zarah dalam naftalena pepejal cecair berubah menjadi
liquid by the particles in the increase energy to and move oleh zarah-zarah
digunakan
absorbed
naphthalene causing their faster . The temperature
by the particles in the
liquid
naphthalene is
the forces of attraction between particles. The particles begin to move
to form a
gas
Tenaga haba
diserap
. The temperature oleh zarah-zarah dalam
remains constant cecair
absorbed
akan
used
to
freely
.
naftalena digunakan untuk mengatasi bebas gas untuk membentuk . Suhu
gas by the particles in the faster . The temperature energy to incerease and move
Heat energy is
causing their increases .
diserap oleh zarah-zarah gas naftalena menyebabkan tenaga Tenaga haba lebih cepat meningkat dan zarah-zarah bergerak dengan . Suhu semakin
kinetik
kinetic
akan bertambah
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Gas
untuk mengatasi tetap .
. Suhu adalah
kinetik naftalena menyebabkan tenaga lebih cepat meningkat . Suhu semakin .
daya tarikan antara zarah-zarah. Zarah-zarah mula bergerak tetap adalah .
E to F E ke F
to . The
cecair
dan zarah-zarah bergerak dengan
overcome
Liquid and Gas
liquid
. diserap
Heat energy D to E D ke E
used
.
absorbed
increases
akan
.
naphthalene is
daya tarikan antara zarah-zarah supaya
Heat energy kinetic
kinetik
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MODULE • Chemistry Form 4
completely changes to become a liquid is called the melting point . During the melting process, the temperature remains unchanged because heat energy absorbed by the particles used is to overcome the forces between particles so that the solid change to turn into a liquid . The constant temperature at which a
3
solid
pepejal
takat lebur berubah kepada keadaan cecair dipanggil diserap oleh zarah-zarah Semasa proses peleburan, suhu tidak berubah kerana haba yang mengatasi cecair daya tarikan antara zarah supaya pepejal berubah menjadi .
Suhu tetap di mana suatu
. digunakan
liquid
completely changes to become a gas is called the absorbed During the boiling process, the temperature remains unchanged because heat energy The constant temperature at which a
4
used
is
to
overcome
untuk
boiling point
.
by the particles
the forces between particles so that the liquid change to turn into a gas.
Suhu tetap di mana suatu bahan dalam keadaan
cecair
takat didih berubah kepada keadaan gas dipanggil . diserap digunakan oleh zarah-zarah untuk
Semasa proses pendidihan, suhu tidak berubah kerana haba yang mengatasi daya tarikan antara zarah supaya cecair berubah menjadi gas.
The Explanation for the Cooling Process of Matter: / Penerangan Proses Penyejukan Bahan:
The cooling curve of naphthalene:
1
Lengkung penyejukan naftalena: Temperature/°C Suhu/°C
P Q
R S Time/s Masa/s
slower When the liquid is cooled, the particles in the liquid release energy and move decreases. As the energy is released to the surrounding, the state of matter will change.
2
cecair Apabila cecair disejukkan, zarah membebaskan tenaga dan dibebaskan ke persekitaran. berubah semasa tenaga Point Titik
P to Q P ke Q
bergerak
as its energy content
semakin perlahan. Keadaan jirim
State of matter
Explanation
Liquid
Heat is released/given out to the surrounding by the particles in the liquid naphthalene. liquid lose their kinetic energy and move slower. The The particles in the temperature decreases .
Keadaan jirim
Penerangan
dibebaskan ke persekitaran oleh zarah-zarah dalam Haba cecair kinetik kehilangan tenaga dan bergerak
cecair
naftalena. Zarah-zarah dalam semakin perlahan. Suhu semakin menurun
.
The heat released to the surrounding by the particles in liquid naphthalene is balanced heat solid . energy released as the particles attract one another to form a by the Q to R Q ke R
R to S
m
Solid
The temperature
remains constant
.
dibebaskan cecair diimbangi ke persekitaran oleh zarah-zarah dalam naftalena oleh Haba haba terbebas tenaga yang apabila zarah-zarah tertarik antara satu sama lain untuk membentuk pepejal tetap . Suhu adalah .
The particles in the solid naphthalene releases heat and vibrate decreases . Zarah-zarah dalam pepejal naftalena menurun Suhu semakin .
membebaskan
slower . The temperature
tenaga dan bergetar dengan
lebih perlahan
.
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Liquid and Solid
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Chemistry Form 4 • MODULE
3
freezing point changes to a solid is called . During the freezing process, the temperature remains unchanged because the heat released to the surrounding is balanced by the solid heat released when the liquid particles rearrange themselves to become a .
The constant temperature at which a
liquid
takat beku berubah kepada keadaan pepejal dipanggil . Semasa proses dibebaskan diimbangi ke persekitaran oleh haba yang terbebas pembekuan, suhu tidak berubah kerana haba yang pepejal . apabila zarah-zarah cecair menyusun semula untuk membentuk
Suhu tetap di mana suatu
cecair
Keadaan Fizik Bahan pada Sebarang Suhu: / Physical State Of A Substance At Any Given Temperature: 1
A substance is in
solid
state if the temperature of the substance is below melting point pepejal
Suatu bahan berada dalam keadaan 2
A substance is in
liquid
state if the temperature of the substance is between melting and boiling points. cecair
Suatu bahan berada dalam keadaan 3
A substance is in
gas
jika suhu bahan tersebut lebih rendah daripada takat leburnya.
jika suhu bahan tersebut berada antara takat lebur dan takat didihnya.
state if the temperature of the substance is above boiling point.
Suatu bahan berada dalam keadaan
gas
jika suhu bahan tersebut lebih tinggi daripada takat didihnya.
EXERCISE / LATIHAN 1
The table below shows substances and their chemical formula. Jadual di bawah menunjukkan bahan dan formula kimia masing-masing. Substance / Bahan
Chemical formula / Formula kimia
Type of particle / Jenis zarah
Silver / Argentum
Ag
Atom
Potassium oxide / Kalium oksida
K2O
Ion
Ammonia / Ammonia
NH3
Molecule
Chlorine / Klorin
Cl2
Molecule
(a) State the type of particles that made up each substance in the table. Nyatakan jenis zarah yang membentuk bahan dalam jadual di atas.
(b) Which of the substances are element? Explain your answer. Yang manakah antara bahan tersebut merupakan suatu unsur? Jelaskan jawapan anda.
Silver and chlorine. Silver and chlorine are made up of one type of atom (c) Which of the substance are compound? Explain your answer. Yang manakah antara bahan tersebut merupakan suatu sebatian? Jelaskan jawapan anda.
Potassium oxide and ammonia. Potassium oxide and ammonia are made up of two different elements 2
The table below shows the melting and boiling points of substance P, Q and R. Jadual di bawah menunjukkan takat lebur dan takat didih bagi bahan P, Q dan R. Melting point / Takat lebur / °C
Boiling point / Takat didih / °C
P
–36
6
Q
–18
70
R
98
230
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MODULE • Chemistry Form 4
(a) (i)
What is meant by ‘melting point’? Apakah yang dimaksudkan dengan ‘takat lebur’?
The constant temperature at which a solid charges to a liquid at particular pressure
(ii) What is meant by ‘boiling point’? Apakah yang dimaksudkan dengan ‘takat didih’?
The constant temperature at which a liquid changes to a gas at particular pressure (b) Draw the particles arrangement of substances P, Q and R at room condition. Lukis susunan zarah P, Q dan R pada keadaan bilik.
Substance P / Bahan P
(c) (i)
Substance Q / Bahan Q
Substance R / Bahan R
What is the substance that exist in the form of liquid at 0°C. Nyatakan bahan yang wujud dalam keadaan cecair pada suhu 0°C.
P, Q
(ii) Give reason to your answer. Jelaskan jawapan anda.
The temperature 0°C is above the melting point of Q and below the boiling point of Q (d) (i)
Substance Q is heated from room temperature to 100°C. Sketch a graph of temperature against time for the heating of substance Q. Bahan Q dipanaskan dari suhu bilik hingga 100°C. Lakarkan graf suhu melawan masa bagi pemanasan bahan Q terhadap masa untuk pemanasan bahan Q.
Temperature/°C
70
Time/s (ii) What is the state of matter of substance Q at 70°C? Apakah keadaan fizik bahan Q pada 70°C?
Liquid and gas (e) Compare the melting point of substances Q and R. Explain your answer. Bandingkan takat lebur bahan Q dan R. Terangkan jawapan anda.
The melting point of substance R is higher than subtance Q. The attraction force between particles in substance R
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Chemistry Form 4 • MODULE
3
The melting point of acetamide can be determined by heating solid acetamide until it melts as shown in the diagram below. The temperature of acetemide is recorded every three minutes when it is left to cool down at room temperature. Takat lebur asetamida boleh ditentukan dengan memanaskan pepejal asetamida sehingga lebur seperti dalam rajah di bawah. Suhu asetamida dicatatkan setiap tiga minit semasa disejukkan pada suhu bilik. Thermometer / Termometer Boiling tube / Tabung didih Water / Air Acetamide / Asetamida
(a) What is the purpose of using water bath in the experiment? Apakah tujuan menggunakan kukus air dalam eksperimen ini?
To ensure even heating of acetemide. Acetamide is easily combustible. (b) State the name of another substance which its melting point can also be determined by using water bath as shown in the above diagram. Namakan satu bahan lain yang mana takat leburnya boleh ditentukan dengan menggunakan kukus air seperti rajah di atas.
Naphthalene (c) Sodium nitrate has a melting point of 310°C. Can the melting point of sodium nitrate be determined by using the water bath as shown in the diagram? Explain your answer. Natrium nitrat mempunyai takat lebur 310°C. Bolehkah takat lebur natrium nitrat ditentukan dengan menggunakan kukus air seperti yang ditunjukkan dalam rajah di atas? Jelaskan jawapan anda.
No, because the melting point of water is 100°C which is less than the melting point of sodium nitrate. (d) Why do we need to stir the acetemide in the boiling tube in above experiment? Mengapakah asetamida dalam tabung didih itu perlu dikacau sepanjang eksperimen?
To make sure the heat is distributed evenly (e) The graph of temperature against time for the cooling of liquid acetamide is shown below. Rajah di bawah menunjukkan graf suhu melawan masa untuk penyejukan cecair asetamida. Temperature / Suhu/ °C
T3 T2
Q
R
T1
(i) What is the freezing point of acetamide?
Time / Masa/s
Apakah takat beku asetamida?
T2°C (ii) The temperature between Q and R is constant. Explain. Suhu antara titik Q dan R adalah tetap. Jelaskan.
The heat lost to the surrounding is balanced by the heat released when the liquid particles rearrange themselves to become solid. (f) Acetemide exists as molecules. State the name of another compound that is made up of molecules. Asetamida wujud sebagai molekul. Namakan sebatian lain yang terdiri daripada molekul.
Water/naphthalene (g) What is the melting point of acetamide? Apakah takat lebur asetamida? n io
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MODULE • Chemistry Form 4
The Atomic Structure / Struktur Atom History of the development of atomic models:
1
Sejarah perkembangan model atom: Scientist Saintis
Atomic Model
Discovery
Model atom
Penemuan
(i)
Matter is made up of particles called
atoms
.
Jirim terdiri daripada zarah-zarah dipanggil
atom
.
created
(ii) Atoms cannot be
Dalton
dicipta
Atom tidak boleh
, destroyed or dimusnah
,
Positively charged sphere Sfera bercas
positif
Thomson Electron charges negative Elektron
(i)
sama
nukleus
bercas positif
(ii)
Nukleus mengandungi proton
, zarah subatom yang pertama.
Proton
yang merupakan pusat bagi atom dan
.
is a part of the nucleus.
Proton
(iii)
yang mengandungi zarah
Discovered the nucleus as the centre of an atom and positively charged . Menjumpai
bergerak di luar
mengandungi Nucleus that contain proton
elektron
positif Atom adalah sfera yang bercas elektron bercas negatif dipanggil .
Electron moves outside the nucleus
Rutherford
.
(ii) Atom is sphere of positive charge which embedded with negatively charged particles called electrons .
(i)
nukleus
.
.
Discovered the electrons , the first subatomic particle. Menjumpai
bercas negatif
Elektron
atau
identical .
(iii) Atoms from the same element are Atom daripada unsur sama adalah
divided
dibahagi
adalah sebahagian daripada nukleus.
Electron move outside the nucleus. Elektron
bergerak di sekeliling nukleus.
(iv) Most of the mass of the atom found in the Nukleus
nucleus .
mempunyai hampir semua jisim atom.
Shell
Neils Bohr
Nucleus that contain proton
(i)
Discovered the existence of electron
Nukleus mengandungi proton
(ii) Electrons move in the
petala
Menjumpai kewujudan Elektron
shells
.
elektron.
shells
around the nucleus.
bergerak di dalam petala mengelilingi
nukleus
.
Electron
Shell
James Chadwick
Nucleus that contain proton and neutron Nukleus mengandungi proton dan neutron
Electron
(i)
Discovered the existence of
proton
.
Nukleus mengandungi zarah-zarah neutral dipanggil proton zarah-zarah bercas positif dipanggil .
neutron
dan
(iii) The mass of a neutron and proton is almost the same. neutron
dan
proton
adalah hampir sama.
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(ii) Nucleus of an atom contains neutral particles called neutron and positively charged particles called
Jisim m
neutron .
neutron
Menjumpai kewujudan
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Chemistry Form 4 • MODULE
2
The structure of an atom: / Struktur Atom: Shell / Petala Nucleus that contain proton and neutron Nukleus yang mengandungi proton dan neutron Electron / Elektron
nucleus
(a) An atom has a central Atom mempunyai
nucleus
(b) The
Nukleus
nukleus
shells
and electrons that move in the
around the nucleus.
petala
di tengahnya dan elektron bergerak di dalam
mengelilingi nukleus tersebut.
contains protons and neutrons. mengandungi proton dan neutron.
+1 . Each electron has an electrical charge of –1 . The neutron has no (c) Each proton has charge of charge neutral (it is ). An atom has the same number of protons and electrons, so the overall charge zero of atom is . Atom is of ion will be studied in Chapter 4)
. (If an atom loses or gains electrons it is called an ion – formation
(ianya adalah neutral ). sifar . Atom Setiap atom mempunyai bilangan proton dan elektron yang sama, oleh itu cas keseluruhan bagi atom adalah neutral . (Suatu atom akan membentuk ion apabila ia kehilangan atau menerima elektron – pembentukan ion akan adalah
Setiap proton bercas
+1
neutral
–1
. Setiap elektron bercas
. Neutron tidak mempunyai
cas
dipelajari dalam Tajuk 4.)
(d) The relative mass of a neutron and a proton which are in the nucleus is 1. The mass of an atom is obtained mainly from the number of proton and neutron . proton
Jisim relatif proton dan neutron di dalam nukleus ialah 1. Jisim suatu atom diperoleh daripada jumlah bilangan neutron dan bilangan .
1 (e) The mass of an electron can be ignored as the mass of an electron is about times the size of a proton or 1 840 neutron. Jisim elektron boleh diabaikan kerana ia terlalu kecil iaitu 3
1 daripada jisim proton dan neutron. 1 840
Complete the following table: Lengkapkan jadual di bawah: Subatomic particles
Symbol
Charge
Relative atomic mass Jisim atom relatif
Kedudukan
Electron/Elektron
e
– (negative)
1 = 0 1 840
In the shells
Proton/Proton
p
+ (positive)
1
In the nucleus
Neutron/Neutron
n
neutral
1
In the nucleus
Zarah subatom
4
Simbol
Cas
Position
Atom is the smallest neutral particle of an element. Atom adalah zarah neutral paling kecil dalam suatu unsur.
Complete the following diagram: / Lengkapkan yang berikut: Na
Na
Na
Na
Sodium element natrium
Unsur
natrium
Na
Na
Na
Na
Na
Na
Sodium element Unsur
natrium
Na
Na
Na
Sodium Atom
atom natrium n io
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Unsur
Sodium element
Na
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MODULE • Chemistry Form 4
Proton number of an element (Refer to Periodic table of an element)
5
Nombor proton sesuatu unsur (Rujuk Jadual Berkala Unsur)
(a) Proton number of an
element
atom
is the number of proton in its
.
atom
Nombor proton sesuatu unsur adalah bilangan proton yang terdapat dalam
.
(b) The number of proton of an atom is also equal to the number of electrons in the atom because atom is neutral . Bilangan proton sesuatu atom adalah sama dengan bilangan elektron dalam atom kerana atom adalah
neutral
.
(c) Every element has its own proton number: Setiap unsur mempunyai nombor protonnya tersendiri:
– Proton number of potassium, K is 19. Potasium in the shells.
atom
Atom
Nombor proton untuk kalium, K ialah 19. 19 elektron di dalam petala.
– Proton number of oxygen, O is 8. Oxygen in the shells. Nombor proton untuk oksigen, O ialah 8. 8 elektron di dalam petala.
has 19 protons in the nucleus and 19 electrons 19 proton
kalium mempunyai
atom
8 protons
has
Atom
di dalam nukleus dan
in the nucleus and 8 electrons 8 proton
oksigen mempunyai
di dalam nukleus dan
Nucleon number of an element (Refer to Periodic table of an element)
6
Nombor nukleon sesuatu unsur (Rujuk Jadual Berkala Unsur)
(a) Nucleon number of an element is the total number of protons and neutrons in the nucleus of its Nombor nukleon sesuatu unsur adalah jumlah bilangan proton dan neutron di dalam nukleus sesuatu
atom
atom
.
.
(b) Nucleon number is also known as a mass number. Nombor nukleon juga dikenali sebagai nombor jisim.
(c) Nucleon number = number of proton + number of neutron. Nombor nukleon = bilangan proton + bilangan neutron. Symbol of Element And Standard Representation For An Atom of Element Simbol Unsur dan Perwakilan Piawai bagi Atom Sesuatu Unsur
The symbol of an element is a short way of representing an element. If the symbol has only one letter, it must be a capital letter. If it has two letters, the first is always a capital letter, while the second is always a small letter.
1
Simbol unsur adalah cara mudah untuk mewakilkan unsur. Jika simbol hanya terdiri daripada satu huruf, maka ia mesti ditulis dengan huruf besar. Tetapi jika simbol terdiri daripada dua huruf, maka huruf pertama merupakan huruf besar dan huruf kedua merupakan huruf kecil.
Example: / Contoh: Element Unsur
Element
Symbol
Element
Symbol
O
Nitrogen/Nitrogen
N
Calcium/Kalsium
Ca
Mg
Sodium/Natrium
Na
Copper/Kuprum
Cu
Potassium/Kalium
K
Chlorine/Klorin
Cl
Simbol
Oxygen/Oksigen Magnesium/Magnesium Hydrogen/Hidrogen
Symbol
H
Unsur
Simbol
Unsur
Simbol
The first letter of each element is capitalised to show that it is a new element. This is helpful when writing a chemical formula. For example KCl. There are two elements chemically bonded in KCl because there are two capital letters represent potassium and chlorine. Huruf yang pertama bagi setiap unsur ditulis dengan huruf besar untuk menunjukkan ia adalah unsur yang baru. Ini sangat berguna semasa menulis formula kimia. Contohnya KCl. Terdapat dua unsur yang terikat secara kimia dalam KCl kerana adanya dua huruf besar yang mewakili kalium dan klorin.
Standard representation symbol represents
2
m
one atom
of an element. It can be written as:
sesuatu unsur. Ianya boleh ditulis sebagai:
Nucleon number/Nombor nukleon
A
Proton number/Nombor proton
Z
X
Symbol of an element/Simbol unsur
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Simbol perwakilan piawai mewakili
satu atom
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Chemistry Form 4 • MODULE
Example: / Contoh:
27 A1 13 – The element is Aluminium. Unsur itu adalah Aluminium.
27
Nombor nukleon Aluminium adalah
– Aluminium has
. .
, 14 neutrons and
13 proton
Atom Aluminium mempunyai 3
13 13
13 protons
. .
– The proton number of Aluminium is Nombor proton Aluminium adalah
27
– The nucleon number of Aluminium is
13
14 neutron
,
electrons. 13 elektron.
dan
Isotope / Isotop (a) Isotopes are atoms of the same element with same number of protons but different number of neutrons. Isotop ialah atom-atom unsur yang mempunyai bilangan proton yang sama tetapi bilangan neutron yang berbeza.
Or / Atau
Isotopes are atoms of the same element with same
proton
number but different
proton
Isotop ialah atom-atom unsur yang mempunyai nombor berbeza.
nucleon
number.
nukleon
yang sama tetapi nombor
yang
Example: / Contoh: 1 1 H
2 1 H
Nucleon number/Nombor nukleon = 1
Nucleon number/Nombor nukleon = 2
Proton number/Nombor proton = 1
Proton number/Nombor proton = 1
Number of neutron/Bilangan neutron = 0
Number of neutron/Bilangan neutron = 1
– Hydrogen-1 and Hydrogen-2 are isotopes. Hydrogen-1 and Hydrogen-2 atoms have the same proton number or the same number of protons but
different
in nucleon number because of the difference in the number of
Atom Hidrogen-1 dan Hidrogen-2 mempunyai nombor proton atau bilangan neutron kerana perbezaan .
– Isotopes have the same arrangements. Isotop mempunyai sifat
chemical kimia
bilangan proton
properties but different
yang sama tetapi nombor nukleon yang
physical
neutron
.
berbeza
properties because they have the same electron
yang sama kerana mempunyai susunan elektron yang sama tetapi sifat
fizik
yang berbeza.
(b) Examples of the usage of isotopes: Contoh kegunaan isotop:
i.
Medical field Bidang perubatan
–
To detect brain cancer.
–
To detect thrombosis (blockage in blood vessel).
–
Sodium-24 is used to measure the rate of iodine absorption by thyroid gland.
–
Cobalt-60 is used to destroy cancer cells.
–
To kill microorganism in the sterilising process.
Untuk mengesan barah otak. Untuk mengesan trombosis (saluran darah tersumbat). Untuk mengukur kadar penyerapan iodin oleh kelenjar tiroid. Contoh: Natrium-24 Untuk memusnahkan sel barah. Contoh: Kobalt-60 Untuk membunuh mikroorganisma semasa proses pensterilan.
ii.
In the industrial field Bidang industri
–
To detect wearing out in machines.
–
To detect any blockage in water, gas or oil pipes.
Untuk mengesan kehausan enjin.
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MODULE • Chemistry Form 4
–
To detect leakage of pipes underground.
–
To detect defects/cracks in the body of an aeroplane.
Untuk mengesan kebocoran paip bawah tanah. Untuk mengesan keretakan atau kecacatan pada badan kapal terbang.
iii.
In the agriculture field Bidang pertanian
–
To detect the rate of absorption of phosphate fertilizer in plants.
–
To sterile insect pests for plants.
Untuk mengesan kadar penyerapan baja fosfat oleh tumbuhan. Untuk memandulkan serangga perosak tumbuhan.
iv.
In the archeology field Bidang arkeologi
–
Carbon-14 can be used to estimate the age of artifacts. Karbon-14 untuk menentukan usia sesuatu artifak.
Electron Arrangement
4
Susunan elektron
(a) The electrons are filled in specific shells. Every shell can be filled only with a certain number of electrons. For the elements with atomic numbers 1-20: Elektron diisi dalam petala tertentu. Setiap petala hanya boleh diisi dengan bilangan elektron tertentu. Bagi unsur-unsur yang mempunyai nombor proton 1–20:
2
– First shell can be filled with a maximum of
electrons. 2
Petala pertama boleh diisi dengan bilangan maksimum
– Second shell can be filled with a maximum of Petala kedua boleh diisi dengan bilangan maksimum Petala ketiga boleh diisi dengan bilangan maksimum
electrons.
8
8
– Third shell can be filled with a maximum of
elektron.
8
elektron. electrons.
8
elektron.
First shell is filled with 2 electrons (duplet) Petala pertama diisi 2 elektron (duplet)
Second shell is filled with 8 electrons (octet) Petala kedua diisi 8 elektron (oktet)
Third shell is filled with 8 electrons (octet) Petala ketiga disi 8 elektron (oktet)
(b) Valence electrons are the electrons in the outermost shell of an atom. Elektron valens: Elektron yang diisi dalam petala paling luar suatu atom.
Complete the following table:
5
Lengkapkan jadual berikut:
(a) Draw the electron arrangement and complete the description for each element: Lukis susunan elektron bagi atom dan penerangan bagi setiap unsur berikut: Standard representation of an element Perwakilan piawai unsur
Electron arrangement of an atom Lukiskan susunan elektron bagi atom
Hydrogen Atom Atom Hidrogen
m
Number of protons/Bilangan proton
1
Number of eletrons/Bilangan elektron
1
Number of neutrons/Bilangan neutron
0
Proton number/Nombor proton
1
Nucleon number/Nombor nukleon
1
Electron Arrangement/Susunan elektron
1
H
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Chemistry Form 4 • MODULE
Sodium Atom Atom Natrium
23 Na 11
Na
Number of protons/Bilangan proton
11
Number of electrons/Bilangan elektron
11
Number of neutrons/Bilangan neutron
12
Proton number/Nombor proton
11
Nucleon number/Nombor nukleon
23
Electron Arrangement/Susunan elektron
2.8.1
(b) Choose the correct statement for the symbol of element X. Pilih pernyataan yang betul bagi simbol unsur X. 23 Na 11 Statement Pernyataan
Element X has 11 proton number. Unsur X mempunyai 11 nombor proton.
The proton number of element X is 11. Nombor proton unsur X ialah 11.
The proton number of atom X is 11. Nombor proton atom X ialah 11.
The number of proton of element X is 11. Bilangan proton unsur X ialah 11.
The number of proton of atom X is 11. Bilangan proton atom X ialah 11.
Nucleon number of element X is 23. Nombor nukleon unsur X ialah 23.
Nucleon number of atom X is 23. Nombor nukleon atom X ialah 23.
Number of nucleon of element X is 23. Bilangan nukleon unsur X ialah 23.
Atom X has 23 nucleon number. Atom X mempunyai 23 nombor nukleon.
Neutron number of atom X is 12. Nombor neutron atom X ialah 12.
Number of neutron of atom X is 12. Bilangan neutron atom X ialah 12.
Number of neutron of element X is 12.
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MODULE • Chemistry Form 4
EXERCISE / LATIHAN
Complete the following table:
1
Lengkapkan jadual berikut:
Element Unsur
Hydrogen Hidrogen
Helium Helium
Boron Boron
Carbon Karbon
Nitrogen Nitrogen
Neon Neon
Sodium Natrium
Magnesium Magnesium
Calcium Kalsium
Symbol of element Simbol unsur
Number of proton Bilangan proton
Number of electron Bilangan elektron
Number of neutron Bilangan neutron
Proton number Nombor proton
Nucleon number Nombor nukleon
Electron arrangement Susunan elektron atom
Number of valence electron Bilangan elektron valens
1 1 H
1
1
0
1
1
1
1
4 2 He
2
2
2
2
4
2
2
11 5 B
5
5
6
5
11
2.3
3
12 6 C
6
6
6
6
12
2.4
4
14 7 N
7
7
7
7
14
2.5
5
20 Ne 10
10
10
10
10
20
2.8
8
23 Na 11
11
11
12
11
23
2.8.1
1
24 Mg 12
12
12
12
12
24
2.8.2
2
40 Ca 20
20
20
20
20
40
2.8.8.2
2
The diagram below shows the symbol of atoms P, R and S.
2
Rajah di bawah menunjukkan simbol atom P, R dan S.
35 P 17
12 R 6
37 S 17
(a) What is meant by nucleon number / Apakah maksud nombor nukleon? Nucleon number of an element is the total number of protons and neutrons in the nucleus of its atom (b) What is the nucleon number of P / Apakah nombor nukleon atom P? 35 (c) State the number of neutron in atom P / Nyatakan bilangan neutron atom P. 18 (d) State number of proton in atom P / Nyatakan bilangan proton atom P. 17 (e) (i)
What is meant by isotope / Apakah maksud isotop?
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Isotopes are atoms of the same element with same number of proton but different number of neutrons
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Chemistry Form 4 • MODULE
(ii) State a pair of isotope in the diagram shown / Nyatakan sepasang isotop dalam rajah yang ditunjukkan. P and S
(iii) Give reason for your answer in (e)(ii) / Berikan sebab bagi jawapan di (e)(ii). Atom P and S have same proton number but different nucleon number//number of neutron
(f) An isotope of R has 8 neutron. Write the symbol for the isotope R. Isotop bagi atom R mempunyai 8 neutron. Tuliskan simbol bagi isotop R.
14 R 6 3
The table below shows the number of proton and neutron of atoms of elements P, Q and R. Jadual di bawah menunjukkan bilangan proton dan neutron bagi atom unsur P, Q dan R. Element Unsur
Number of proton Bilangan proton
Number of neutron Bilangan neutron
P
1
0
Q
1
1
R
6
6
(a) Which of the atoms in the above table are isotope? Explain your answer. Berdasarkan jadual di atas, atom yang manakah merupakan isotop? Terangkan jawapan anda.
P and Q. Atom P and Q have same number of proton but different number of neutron // nucleon number. (b) (i)
Write the standard representation of element Q. Tuliskan perwakilan piawai untuk unsur Q.
2 Q 1
(ii) State three information that can be deduced from your answer in (b)(i). Nyatakan tiga maklumat yang boleh didapati daripada jawapan anda di (b)(i).
The proton number of element Q is 1 // Number of proton of atom Q is 1 Nucleon number of element Q is 2 // Atomic mass of atom Q is 2 Number of neutron of atom Q is 1 Nucleus of atom Q contains 1p and 1n (c) (i)
Draw atomic structure for atom of element R. Lukiskan struktur atom bagi atom unsur R.
6 protons + 6 neutrons
(ii) Describe the atomic structure in (c)(i). Huraikan struktur atom di (c)(i).
– The atom consists of 2 parts: the centre part called nucleus and the outer part called electron shell. – The nucleus consists of 6 protons which are positively charged and 6 neutrons which are neutral. – The electrons are in two shells, the first shell consists of two electrons and the second shell consists of four electrons.
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– Electrons move around nucleus in the shells.
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MODULE • Chemistry Form 4
(d) Element R react with oxygen and to produce liquid Z at room temperature. The graph below shows the sketch of the graph when liquid Z at room temperature, 27°C is cooled to –5°C. Unsur R bertindak balas dengan oksigen dan menghasilkan cecair Z pada suhu bilik. Rajah di bawah menunjukkan lakaran graf apabila cecair Z pada suhu bilik, 27°C disejukkan sehingga –5°C. Temperature /°C Suhu /°C
Time /s
0
t1
Masa /s
t2
−5
(i) What is the state of matter of liquid Z from t1 to t2? Explain why is the temperature remain unchanged from t1 to t2. Apakah keadaan jirim Z daripada t1 hingga t2? Terangkan mengapa suhu tidak berubah daripada t1 hingga t2.
Liquid and solid. Heat lost to the surrounding is balanced by the heat released when the particles at 0 °C (ii) Draw the arrangement of particles of Z at 20°C. Lukiskan susunan zarah-zarah Z pada suhu 20°C.
(iii) Describe the change in the particles movement when Z is cooled from room temperature to –5°C. Nyatakan perubahan dalam pergerakan zarah-zarah apabila cecair Z disejukkan daripada suhu bilik ke –5°C.
The particles move slower Objective Questions / Soalan Objektif The diagram shows the arrangement of particles for a type of matter that undergoes a change in physical state through process X.
1
3
The diagram below shows the heating curve for substance X. Rajah di bawah menunjukkan lengkung pemanasan bahan X.
Temperature / Suhu °C
Rajah di bawah menunjukkan susunan zarah sejenis bahan yang mengalami perubahan keadaan fizik melalui proses X.
U S Q
X
T
R
P
Time (m) Masa (m)
Which region of the graph does boiling process occur?
What is process X?
Bahagian manakah pada graf berlaku proses pendidihan?
Apakah proses X ?
A B
Melting Peleburan
Boiling Pendidihan
C D
Sublimation Pemejalwapan
Antara bahan berikut, yang manakah mengalami pemejalwapan apabila dipanaskan?
A
Sulphur Sulfur
Ammonium chloride Ammonium klorida
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Sodium chloride Natrium klorida
C D
ST TU
Which of the following information is true? Antara pernyataan berikut, yang manakah adalah betul? Change of state Perubahan keadaan
Process Proses
Heat energy Tenaga haba
A
Solid → Liquid
Melting
Released
Pepejal → Cecair
Peleburan
Dibebaskan
B
Liquid → Gas
Evaporation
Released
Cecair → Gas
Penyejatan
Dibebaskan
C
Gas → Solid
Sublimation
Released
Gas → Pepejal
Pemejalwapan
Dibebaskan
D
Gas → Liquid
Condensation Kondensasi
Absorbed
Glucose Glukosa
PQ QR
Gas → Cecair
Diserap
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Which of the following substances can undergo sublimation when heated?
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Freezing Pembekuan
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Chemistry Form 4 • MODULE
5
The diagram below shows the graph of temperature against time when a liquid Y is cooled. Rajah di bawah menunjukkan graf suhu melawan masa apabila cecair Y disejukkan.
Substance Bahan
Melting point/°C Takat lebur/°C
Boiling point/°C Takat didih/°C
S
–182
–162
T
–23
77
U
–97
65
V
41
182
W
132
290
Temperature / Suhu °C t3
P Q
t2
R
Which substance exists as liquid at room temperature? t1
Bahan yang manakah wujud sebagai cecair pada suhu bilik?
S
A
Time (m) Masa (m)
B
Which of the following statements are true about the curve? Antara pernyataan berikut, yang manakah adalah betul tentang lengkung itu?
I
At Q, liquid Y begins to freeze.
II
At PQ, particles in Y absorb heat from the surroundings.
III
Liquid Y freezes completely at S.
IV
The freezing point of Y is t2°C.
8
Pada Q, cecair Y mula membeku.
C
S only S sahaja
D
S and T only S dan T sahaja
Rajah di bawah menunjukkan perwakilan piawai atom kuprum.
64 Cu 29
Cecair Y membeku dengan lengkap pada S.
A B 6
C
I and III only I dan III sahaja
D
I and IV only I dan IV sahaja
Which of the following is correct based on the symbol the diagram?
II and III only
Antara berikut, yang manakah betul berdasarkan rajah di atas?
II dan III sahaja
Rajah di bawah menunjukkan graf suhu melawan masa apabila pepejal Z dipanaskan.
Temperature / Suhu °C 9
0
1
2
3
4
5
6
7
8
9
29
64
29
B
35
29
64
C
64
35
29
D
29
64
35
The diagram below shows the standard representation of beryllium atom.
Apakah bilangan elektron valens bagi atom berillium?
Masa (m)
Antara berikut, yang manakah adalah benar pada minit keempat?
7
A
What is the number of valence electrons of beryllium atom? A B
Which of the following is true during the fourth minute?
D
Number of electron Bilangan elektron
9 Be 4 Time (m)
C
Nucleon number Nombor nukleon
Rajah di bawah menunjukkan perwakilan piawai atom berillium.
80
B
Proton number Nombor proton
II and IV only II dan IV sahaja
The diagram below shows the graph of temperature against time when solid Z is heated.
A
V and W only V dan W sahaja
The diagram below shows standard representation of an atom copper.
Pada PQ, zarah dalam Y menyerap haba dari persekitaran.
Takat beku bagi Y adalah t2°C.
T and U only T dan U sahaja
All the molecules are in random motion. Semua molekul bergerak secara rawak. All the molecules are closely packed and in random motion. Semua molekul sangat rapat dan bergerak secara rawak. All the molecules are vibrating at fixed positions. Semua molekul bergetar pada kedudukan tetap. Some of the molecules are vibrating at fixed positions but some are in random motion. Sebahagian molekul bergetar pada kedudukan tetap dan sebahagian bergerak secara rawak.
The table shows the melting points and boiling points of substances S, T, U, V and W.
C D
4 7
The table below shows the proton number and the number of neutrons for atoms of elements W, X, Y and Z. Jadual di bawah menunjukkan nombor proton dan bilangan neutron bagi atom unsur W, X, Y dan Z. Element Atom
Proton number Nombor proton
Number of neutrons Bilangan neutron
W 7 7 X 8 8 Y 8 9 Z 9 10 Which of the following pair of elements is isotope? Antara pasangan berikut, yang manakah adalah isotop?
A B
W and X W dan X
W and Y W dan Y
C D
X and Y X dan Y
Y and Z Y dan Z
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Jadual di bawah menunjukkan takat lebur dan takat didih bahan S, T, U, V dan W.
10
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MODULE • Chemistry Form 4
2
CHEMICAL FORMULA AND EQUATIONS FORMULA DAN PERSAMAAN KIMIA RELATIF MASS / JISIM RELATIF
• RELATIVE ATOMIC MASS / JISIM ATOM RELATIF (JAR)
– To state the meaning of relative mass and solve numerical problems Menyatakan maksud jisim atom relatif dan menyelesaikan masalah pengiraan
• RELATIVE FORMULA MASS / JISIM FORMULA RELATIF (JFR)
– To state the meaning of RAM, RMM and RFM based on carbon-12 scale Menyatakan maksud JAR, JMR dan JFR berdasarkan skala karbon-12
• RELATIVE MOLECULAR MASS / JISIM MOLEKUL RELATIF (JMR)
– To calculate RAM, RMM and RFM using the chemical formulae of various substances Menghitung JAR, JMR dan JFR menggunakan formula kimia beberapa bahan
MOLE CONCEPT / KONSEP MOL
• MOLE AND THE NUMBER OF PARTICLES / MOL DAN BILANGAN ZARAH
– To solve numerical problems involving mole and the number of atoms/ ions/ molecules Menyelesaikan masalah pengiraan melibatkan mol dan bilangan atom, ion dan molekul
• MOLE AND THE MASS OF SUBSTANCES / MOL DAN JISIM BAHAN
– To solve numerical problems involving mole and the mass of substances, number of particles and volume of gas using mole concept Menyelesaikan masalah pengiraan melibatkan mol, jisim bahan, bilangan zarah dan isipadu gas menggunakan konsep mol
• MOLE AND THE VOLUME OF GAS / MOL DAN ISIPADU GAS
– To solve numerical problems involving mole and the mass of substances, number of particles and volume of gas using mole concept Menyelesaikan masalah pengiraan melibatkan mol, jisim bahan, bilangan zarah dan isipadu gas menggunakan konsep mol
CHEMICAL FORMULA AND EQUATIONS / FORMULA DAN PERSAMAAN KIMIA
• EMPIRICAL FORMULA / FORMULA EMPIRIK
– Stating the purpose and describe the empirical formula laboratory activities to determine the formula empirical Menyatakan maksud formula empirik dan menghuraikan aktiviti makmal untuk menentukan formula empirik
• MOLECULAR FORMULA / FORMULA MOLEKUL
– Solve calculation problems involving empirical formula Menyelesaikan masalah pengiraan melibatkan formula empirik
• CHEMICAL FORMULAE / FORMULA KIMIA
– To write formula of anion and cation and to write chemical formula for ionic compounds Menulis formula kation dan anion dan menulis formula kimia untuk sebatian ion
• CHEMICAL EQUATIONS / PERSAMAAN KIMIA
– Write a balanced chemical equation and solve problems arrangements involving the mole concept
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Menulis persamaan kimia seimbang dan menyelesaikan masalah pengiraan yang melibatkan konsep mol
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Chemistry Form 4 • MODULE
RELATIVE ATOMIC MASS (RAM) / JISIM ATOM RELATIF (JAR) 1
A single atom is too small and light and cannot be weighed directly. Satu atom adalah terlalu ringan, kecil dan tidak dapat ditimbang secara langsung.
2
The best way to determine the mass of a single atom is to compare its mass to the mass of another atom of an element that is used as a standard. Cara yang paling sesuai untuk menentukan jisim satu atom ialah dengan membandingkan jisimnya dengan jisim suatu atom unsur lain yang dianggap sebagai piawai.
3
Hydrogen was the first element to be chosen as the standard for comparing mass because the hydrogen atom is the lightest atom with a mass of 1.0 a.m.u (atomic mass unit). Hidrogen adalah unsur pertama dipilih sebagai piawai untuk membandingkan jisim kerana atom hidrogen adalah unsur yang paling ringan dengan jisim 1.0 u.j.a (unit jisim atom).
Example: Contoh:
• The mass of one helium atom is four times larger than one hydrogen atom. Jisim satu atom Helium adalah 4 kali lebih besar daripada satu atom hidrogen.
• RAM for He is 4. JAR untuk He ialah 4. 4
On the hydrogen scale, the relative atomic mass of an element means the mass of one atom of the element compared to the mass of a single hydrogen atom: Pada skala hidrogen, jisim atom relatif suatu unsur ditakrifkan sebagai jisim satu atom unsur berbanding jisim satu atom hidrogen:
Relative atomic mass of an element (RAM) / Jism atom relatif suatu unsur (JAR) =
The average mass of one atom of the element / Jisim purata satu atom unsur Mass of one hydrogen atom / Jisim satu atom hidrogen
• RAM has no unit. JAR tiada unit.
• The new standard used today is the carbon-12 atom. Piawai yang digunakan sekarang adalah berdasarkan atom karbon-12.
1 • RAM based on the carbon-12 scale is the mass of one atom of the element compared with of the mass of an 12 atom of carbon-12: JAR berdasarkan skala atom karbon-12 adalah jisim satu atom unsur berbanding dengan
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• Relative atomic mass of an element (RAM) / Jisim atom relatif suatu unsur (JAR) The average mass on one atom of the element / Jisim purata satu atom unsur = 1 × The mass of an atom of carbon-12 / Jisim satu atom karbon-12 12
1 jisim satu atom karbon-12: 12
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MODULE • Chemistry Form 4
RELATIVE MOLECULAR MASS (RMM) / RELATIVE FORMULA MASS (RFM) JISIM MOLEKUL RELATIF (JMR) / JISIM FORMULA RELATIF (JFR)
RMM / JMR =
1
The average mass on one atom of the element / Jisim purata satu molekul
1 × The mass of an atom of carbon-12 / Jisim satu atom karbon-12 12 RMM is obtained by adding up the RAM of all the atoms that are present in the molecule.
2
JMR diperoleh dengan menambahkan JAR semua atom yang terdapat dalam satu molekul. Molecular substance
Molecular formula
Relative molecular mass
O2
2 × 16 = 32
Water / Air
H2O
2 × 1 + 16 = 18
Carbon dioxide / Karbon dioksida
CO2
12 + 2 × 16 = 44
Ammonia / Ammonia
NH3
14 + 3 × 1 = 17
Bahan molekul
Formula molekul
Oxygen / Oksigen
Jisim molekul relatif
[Relative atomic mass / Jisim atom relatif : O = 16, H = 1, C = 12, N = 14]
For ionic substances, RMM is replaced with Relative Formula Mass (RFM).
3
Untuk sebatian ion, JMR digantikan dengan Jisim Formula Relatif (JFR). Substance
Chemical formula
Relative molecular mass
Sodium chloride / Natrium klorida
NaCl
23 + 35.5 = 58.5
Potassium oxide / Kalium oksida
K2O
2 × 39 + 16 = 94
CuSO4
64 + 32 + 4 × 16 = 160
(NH4)2CO3
2 [14 + 4 × 1] + 12 + 3 × 16 = 96
Aluminium nitrate / Aluminium nitrat
Al(NO3)3
27 + 3 [14 + 3 × 16] = 213
Calcium hydroxide / Kalsium hidroksida
Ca(OH)2
40 + 2 [16 + 1] = 74
Lead(II) hydroxide / Plumbum(II) hidroksida
Pb(OH)2
207 + 2 [16 + 1] = 241
CuSO45H2O
64 + 32 + 4 × 16 + 5 [2 × 1 + 16] = 250
Bahan
Copper(II) sulphate / Kuprum(II) sulfat Ammonium carbonate / Ammonium karbonat
Hydrated copper(II) sulphate / Kuprum(II) sulfat terhidrat
Formula kimia
Jisim formula relatif
[Relative atomic mass / Jisim atom relatif : Na = 23, Cl = 35.5, K = 39, O = 16, Cu = 64, S = 32, N = 14, H = 1, C = 12, Al = 27, Ca = 40, Pb = 207]
(i) The formula of metal oxide of M is M2O3. Its relative formula mass is 152. What is the relative atomic mass of metal M? Oksida logam M mempunyai formula M2O3. Jisim formula relatif ialah 152. Apakah jisim atom relatif logam M?
M = RAM for M 2M + 3 × 16 = 152 M = 52
m
Fosforus membentuk sebatian klorida dengan formula PClx. Jisim molekul relatifnya adalah 208.5. Hitungkan nilai x. [Relative atomic mass / Jisim atom relatif : P = 31, Cl = 35.5]
1 + x × 35.5 = 208.5 3 35.5x = 208.5 – 31 35.5x = 177.5 x = 5
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(ii) Phosphorus forms a chloride with a formula PClx. Its relative molecular mass is 208.5. Calculate the value of x.
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Chemistry Form 4 • MODULE
MOLE CONCEPT / KONSEP MOL Mole and the Number of Particles / Bilangan Mol dan Bilangan Zarah 1 2
To describe the amount of atoms, ions or molecules, mole is used. Untuk menyatakan jumlah atom, ion atau molekul, unit mol digunakan. A mole is an amount of substance that contains as many particles as the number of atoms in exactly 12 g of carbon-12. Satu mol ialah jumlah bahan yang mengandungi bilangan zarah seperti mana yang terdapat dalam 12 g atom karbon-12.
3
A mole of a substance is the amount of substance which contains a constant number of particles (atoms, ions, molecules), which is 6.02 × 1023. Satu mol bahan adalah jumlah bahan yang mengandungi bilangan zarah yang tetap (atom, molekul, ion) iaitu 6.02 × 1023.
4 5
The number 6.02 × 1023 is called the Avogadro Constant or Avogadro Number (NA). Nombor 6.02 × 1023 dikenali sebagai Pemalar Avogadro atau Nombor Avogadro (NA ). For compounds that exist as molecules/ions, the number of atoms/ions in that compound must be known. Bagi sebatian yang wujud dalam bentuk molekul/ion, bilangan atom/ion dalam sebatian itu mestilah diketahui.
6 7
The symbol of mole is mol. Simbol untuk mol ialah mol. Complete the following table: Lengkapkan jadual berikut: Substance
Formula
Bahan
Formula
Type of particles
Model / Figure
Number of atom per molecule/ Number of positive and negative ion
Model / Rajah
Jenis zarah
Bilangan atom per molekul/ Bilangan ion positif dan negatif
Chlorine / Klorin
Cl2
Molecule
Cl Cl
Water / Air
H2O
Molecule
H O H
Ammonia / Ammonia
NH3
Molecule
H H N H
Sulphur dioxide / Sulfur dioksida
SO2
Molecule
O S O
MgCl2
Ion
[Cl]– [Mg]2+ [Cl]–
Magnesium chloride / Magnesium klorida
Cl : 2 H : 2 O : 1
N : 1 H : 3
S : 1 O : 2
Mg2+ : 1 Cl– : 2
Al : 2 3+
Aluminium oxide / Aluminium oksida 8
Al2O3
Ion
[O]2– [A1]3+ [O]2– [A1]3+ [O]2–
O2– : 3
Relationship between number of moles and number of particles (atoms/ions/molecules): Hubungan bilangan mol dan bilangan zarah (atom/ion/molekul):
Number of moles Bilangan mol 9
× Avogadro Constant / Pemalar Avogadro ÷ Avogadro Constant / Pemalar Avogadro
Number of particles Bilangan zarah
Complete the following: [Differentiate between “mole” dan “molecule”] Lengkapkan yang berikut: [Bezakan antara “mol” dan “molekul”]
(a) 1 mol of Cl2 [Chlorine gas] 1 mol Cl2 [Gas klorin]
(b) 1 mol of NH3 [Ammonia gas]
molecules of chlorine, Cl2 / molekul klorin, Cl2
2 × 6.02 × 1023 atoms of chlorine, Cl / atom klorin, Cl 6.02 × 1023 4
molecules of ammonia, NH3 / molekul ammonia, NH3 1 mol of nitrogen atom, N / mol atom nitrogen, N mol atoms / mol atom 3 mol of hydrogen atoms, H / mol atom hidrogen, H n io
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1 mol NH3 [Gas ammonia]
6.02 × 1023
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MODULE • Chemistry Form 4
0.25 × 6.02 × 1023 molecules of ammonia, NH / molekul ammonia, NH 3 3 0.25 mol of N atoms / mol atom N, 23 number of N atoms / bilangan atom N = 0.25 × 6.02 × 10 1 mol of atoms
1 mol of NH3 4 [Ammonia gas]
(c)
1 mol NH3 4 [Gas ammonia]
1
mol atom
0.75 mol of H atoms / mol atom H, 23 number of H atoms / bilangan atom H = 0.75 × 6.02 × 10
2 mol of Mg2+ ions / mol ion Mg2+, 23 number of Mg2+ ions / bilangan ion Mg2+ = 2 × 6.02 × 10
(d) 2 mol of MgCl2 [Magnesium chloride] 2 mol MgCl2 [Magnesium klorida]
4 mol of Cl– ions / mol ion Cl–, 23 number of Cl- ions / bilangan ion Cl– = 4 × 6.02 × 10 2 × 6.02 × 1023 molecules of SO / molekul SO 2 2 2 mol of S atoms / mol atom S, 23 number of S atoms / bilangan atom S = 2 × 6.02 × 10 3 × 2 = 6 mol of atoms
(e) 2 mol of SO2 [Sulphur dioxide] 2 mol SO2 [Sulfur dioksida]
3 × 2 = 6 mol atom
4 mol of O atoms / mol atom O, 23 number of O atoms / bilangan atom O = 4 × 6.02 × 10
10 Complete the table below: Lengkapkan jadual berikut: Number of moles
Number of particles
Bilangan mol
0.5 0.5
Bilangan zarah
mole of carbon, C
3.01 × 1023 atoms of carbon
mol atom karbon, C
3.01 × 1023 atom karbon
0.2 moles of hydrogen gas, H2
(i)
0.2 mol gas hidrogen, H2
1 1
(ii)
0.2 × 6.02 × 1023
molecules of hydrogen / molekul hidrogen
2 × 0.2 × 6.02 × 1023 atoms of hydrogen / atom hidrogen
6.02 × 1023 molecules of carbon dioxide contains:
mole of carbon dioxide molecules, CO2
6.02 × 1023 molekul karbon dioksida mengandungi:
mol molekul karbon dioksida, CO2
6.02 × 1023 6.02 × 10
23
atoms of C and atom C dan
2 × 6.02 × 1023
2 × 6.02 × 1023
atoms of O.
atom O.
NUMBER OF MOLES AND MASS OF SUBSTANCE / BILANGAN MOL DAN JISIM BAHAN Molar mass / Jisim molar (a) Molar mass is the mass of one mole of any substance / Jisim molar adalah jisim satu mol sebarang bahan. (b) Molar Mass is the relative atomic mass, relative molecular mass and relative formula mass of a substance in g mol–1.
1
Jisim molar adalah jisim atom relatif, jisim molekul relatif dan jisim formula relatif suatu bahan dalam g mol–1. (c) Molar mass of any substance is numerically equal to its relative mass (Relative atomic mass/ relative formula
mass/relative molecular mass). Jisim molar sebarang bahan mempunyai nilai yang sama dengan jisim relatif (Jisim atom relatif/ jisim formula relatif/ jisim molekul relatif).
Example / Contoh: Molar mass of H2O = 18 g mol–1
2
Jisim molar H2O = 18 g mol–1
× RAM/ /RFM/RMM
Mass of 1 mol of H2O = 18 g
Jisim 1 mol H2O = 18 g
Mass of 2 mol of H2O = 2 mol × 18 g mol = 36 g
Jisim 2 mol H2O = 2 mol ×
–1
18
g mol–1 =
Mass of 2.5 mol of H2O = 45 g
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Bilangan mol
÷ RAM/ /RFM/RMM
Mass in gram Jisim dalam gram
÷ JAR/JFR/JMR
mol H2O = 45 g
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Number of moles
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Chemistry Form 4 • MODULE
3
Complete the following table: Lengkapkan jadual berikut: Element/ Compound
Unsur/Sebatian
Copper
Chemical formula
RAM/RMM/RFM
Formula kimia
Cu
RAM/JAR = 64
NaOH
RFM/JFR = 40
Kuprum
Sodium hydroxide
Calculate
JAR/JMR/JFR
Natrium hidroksida
Penghitungan –1 (a) Mass of 1 mol of Cu / Jisim 1 mol Cu : 1 mol × 64 g mol = 64 g 2 mol × 64 g mol–1 = 128 g (b) Jisim 2 mol / Jisim 1 mol : 1 mol × 64 g mol–1 = 32 g 1 1 2 (c) Jisim mol / Jisim mol: 2 2 32 g (d) Mass of 3.01 × 1023 Cu atoms / Jisim 3.01 × 1023 atom Cu:
(a) Mass of 3 mol of sodium hydroxide: Jisim 3 mol natrium hidroksida:
120 g
120 g
(b) Number of moles in 20 g sodium hydroxide: 0.5 mol Bilangan mol natrium hidroksida dalam 20 g:
Oxygen gas Gas oksigen
O2
RMM/JMR = 32
(a) Mass of 2.5 mol of oxygen gas: Jisim 2.5 mol gas oksigen:
0.5 mol
2.5 mol × 32 g mol–1 = 80 g
2.5 mol × 32 g mol–1 = 80 g
(b) Number of moles is 1.5 mol oxygen gas: Bilangan molekul dalam 1.5 mol gas oksigen:
1.5 mol × 6.02 × 1023 1 (c) Number of molecules in mol of oxygen gas: 2 1 Bilangan molekul dalam mol gas oksigen: 2 0.5 mol × 6.02 × 1023 (d) Number of atoms in 2 mol of oxygen gas:
Bilangan atom dalam 2 mol gas oksigen:
Sodium chloride
NaCl
RFM/JFR = 58.5
Zn(NO3)2
RFM/JFR = 189
Natrium klorida
Zinc nitrate Zink nitrat
2 × 2 × 6.02 × 1023
Mass of 0.5 mol of NaCl / Jisim bagi 0.5 mol NaCl: 0.5 mol × 58.5 g mol–1 = 29.25 g Number of moles in 37.8 g of zinc nitrate: Bilangan mol dalam 37.8 g zink nitrat:
37.8 g/189 g mol–1 = 0.2 mol [Relative atomic mass / Jisim atom relatif: Cu = 64, Na = 23, O = 16, H = 1, Cl = 35.5, Zn = 65, N = 14]
NUMBER OF MOLES AND VOLUME OF GAS / BILANGAN MOL DAN ISI PADU GAS 1
Molar volume of a gas: Volume occupied by one mole of any gas is 24 dm3 at room conditions and 22.4 dm3 at
standard temperature and pressure (STP). Isi padu molar gas: Isipadu yang dipenuhi oleh satu mol sebarang gas iaitu 24 dm3 pada keadaan bilik dan 22.4 dm3 pada suhu dan tekanan piawai (STP). 2
The molar volume of any gas is 24 dm3 at room conditions and 22.4 dm3 at STP. Isi padu molar sebarang gas adalah 24 dm3 pada keadaan bilik dan 22.4 dm3 pada STP.
3
Generalisation: One mole of any gas always occupies the same volume under the same temperature and pressure: Umumnya: satu mol sebarang jenis gas menempati isi padu yang sama pada suhu dan tekanan yang sama.
Example / Contoh: (i) 1 mol of oxygen gas, 1 mol ammonia gas, 1 mol helium gas dan 1 mol sulphur dioxide gas occupy the same volume of 24 dm3 at room conditions. 1 mol gas oksigen, 1 mol gas ammonia, 1 mol gas helium dan 1 mol gas sulfur dioksida menempati isi padu yang sama iaitu 24 dm3 pada keadaan bilik.
44.8
(ii) 2 mol of carbon dioxide gas occupies 44.8
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2 mol gas karbon dioksida menempati
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MODULE • Chemistry Form 4
(iii) 16 g of oxygen gas = 0.5 mol of oxygen gas. Therefore, 16 g of oxygen gas occupies a volume of at room conditions [Relative atomic mass: O =16] 0.5 mol gas oksigen. Oleh itu, 16 g gas oksigen menempati isi padu 16 g gas oksigen = [Jisim atom relatif; O = 16]
Number of moles of gas Bilangan mol gas
× 24 dm3 mol–1/ 22.4 dm3 mol–1
12
12
dm3
dm3 pada keadaan bilik.
Volume of gas in dm2 Isi padu gas dalam dm3
÷ 24 dm3 mol–1/ 22.4 dm3 mol–1
Formula for conversion of unit: Formula untuk penukaran unit:
Volume of gas in dm3 Isi padu gas dalam dm3
÷ 24 dm3 mol–1/ 22.4 dm3 mol–1 ÷ (RAM/ /RFM/RMM) g mol–1 Mass in gram (g) Jisim dalam gram (g)
× 24 dm3 mol–1/ 22.4 dm3 mol–1
÷ (JAR/JFR/JMR) g mol–1
Number of moles
÷ (6.02 × 1023)
× (RAM/ /RFM/RMM) g mol–1
Bilangan mol
× (6.02 × 1023)
× (JAR/JFR/JMR) g mol–1
Number of particles Bilangan zarah
EXERCISE / LATIHAN
Relative atomic mass of calcium is 40 based on the carbon-12 scale.
1
Jisim atom relatif kalsium berdasarkan skala karbon-12 ialah 40.
(a) State the meaning of the statement above. Nyatakan maksud penyataan di atas.
Mass of calcium atom is 4 times greater than
1 mass of carbon-12 atom. 12
(b) How many times is one calcium atom heavier than one oxygen atom? [Relative atomic mass: O = 16] Berapa kalikah satu atom kalsium lebih berat daripada satu atom oksigen? [JAR: O = 16]
Relative atomic mass of calcium 40 = = 2.5 times Relative atomic mass of oxygen 16
(c) How many calcium atoms have the same mass as two atoms of bromine? [RAM Br = 80] Berapakah bilangan atom kalsium yang mempunyai jisim yang sama dengan dua atom bromin? [Jisim atom relatif: Br = 80]
Number of calcium atom × 40 = 2 × 80 2 × 80 Number of calcium atom = = 4 40 A sampel of chlorine gas weighs 14.2 g. Calculate / Suatu sampel gas klorin berjisim 14.2 g. Hitungkan: [Relative atomic mass / Jisim atom relatif : Cl = 35.5] (a) Number of moles of chlorine atoms / Bilangan mol atom klorin. 14.2 Number of mol of chlorine atoms, Cl = = 0.4 mol 35.5
2
(b) Number of moles of chlorine molecules (Cl2) / Bilangan mol molekul klorin (Cl2 ). 14.2 Number of mol of chlorine molecule, Cl2 = = 0.2 mol 71 (c) Volume of chlorine gas at room conditions / Isi padu gas klorin pada keadaan bilik. [Molar volume of gas = 24 dm3 mol–1 at room temperature and pressure] [Isi padu molar gas = 24 dm3 mol–1 pada suhu dan tekanan piawai]
m
Volume of chlorine gas = 0.2 mol × 24 dm3 mol–1 = 4.8 dm3
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Chemistry Form 4 • MODULE
3
(a) Calculate the number of atoms in the following substances / Hitungkan bilangan atom yang terdapat dalam bahan berikut: [Relative atomic mass: N = 14; Zn = 65; Avogadro Constant = 6.02 × 1023]
[Jisim atom relatif: N = 14; Zn = 65; Pemalar Avogadro = 6.02 × 1023] (i) 13 g of zinc / 13 g zink
(ii) 5.6 g of nitrogen gas / 5.6 g gas nitrogen 5.6 Number of mol of N atom = = 0.4 mol 14 Number of N atom = 0.4 × 6.02 × 1023 = 2.408 × 1023
13 = 0.2 mol 65 Number of zinc atom = 0.2 × 6.02 × 1023 = 1.204 × 1023 Number of mol of zinc atom =
(b) Calculate the number of molecules in the following substances / Hitungkan bilangan molekul dalam bahan berikut: [Relative atomic mass: N = 14, H = 1, Cl = 35.5, Avogadro Constant = 6.02 × 1023]
[Jisim atom relatif: N = 14, H = 1, Cl = 35.5, Pemalar Avogadro = 6.02 × 1023] (i) 8.5 g of ammonia gas, NH3 / 8.5 g gas ammonia, NH3
(ii) 14.2 g of chlorine gas, Cl2 / 14.2 g gas klorin, Cl2 14.2 × 6.02 × 1023 71 = 1.2 × 1023
4
A gas jar contains 240 cm3 of carbon dioxide gas. Calculate:
8.5 × 6.02 × 1023 17 = 2.408 × 1023
Suatu balang gas berisi 240 cm3 gas karbon dioksida. Hitungkan:
[Relative atomic mass: C = 12, O = 16; Molar volume of gas = 24 dm3 mol–1 at room conditions] [Jisim atom relatif: C = 12, O = 16; Isi padu molar gas: 24 dm3 mol–1 pada keadaan bilik] (a) Number of moles of carbon dioxide gas / Bilangan mol gas karbon dioksida:
Number of moles of CO2 =
240 = 0.01 mol 24 000
(b) Number of molecules of carbon dioxide gas / Bilangan molekul gas karbon dioksida: Number of molecules of CO2 = 0.01 × 6.02 × 1023 = 6.02 × 1021 (c) Mass of carbon dioxide gas / Jisim gas karbon dioksida: Mass of CO2 = 0.01 mol × [12 + 2 × 16] g mol–1 = 0.44 g
5
What is the mass of chlorine molecules (Cl2) that contains twice as many molecules as that found in 3.6 g of water?
Berapakah jisim molekul klorin (Cl2 ) yang mengandungi dua kali ganda bilangan molekul yang terdapat dalam 3.6 g air? [Relative atomic mass / Jisim atom relatif : H = 1, O = 16, Cl = 35.5]
Number of moles of chlorine molecule = 2 × no of mol in H2O 3.6 = 2 × = 0.4 mol 18 Mass of Cl2 = 0.4 × 71= 28.4 g 6
Calculate the mass of carbon that has the same number of atoms as found in 4 g of magnesium. Hitungkan jisim karbon yang mempunyai bilangan atom yang sama seperti yang terdapat dalam 4 g magnesium. [Relative atomic mass / Jisim atom relatif : C = 12, Mg = 24]
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2 g
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MODULE • Chemistry Form 4
Compare the number of molecule in 32 g of sulphur dioxide (SO2) with 7 g of nitrogen gas (N2). Explain your answer.
7
Bandingkan bilangan molekul dalam 32 g sulfur dioksida (SO2 ) dengan 7 g gas nitrogen (N2 ). Terangkan jawapan anda. [Relative atomic mass / Jisim atom relatif : S = 32, O = 16, N = 14]
Number of moles of molecules in 32 g SO2 =
32 = 0.5 mol 64
7 = 0.25 mol 28 Number of molecule in 32 g SO2 is two times more than 7 g N2. Number of mole in sulphur dioxide molecule is two times more than number of mole of nitrogen molecule. Number of moles of molecules in 7 g N2 =
Compare number of atoms in 1.28 g of oxygen to the number of atoms in 1.3 g of zinc. Explain your answer.
8
Bandingkan bilangan atom dalam 1.28 g oksigen dengan bilangan atom dalam 1.3 g zink. Terangkan jawapan anda. [Relative atomic mass / Jisim atom relatif : O = 16, Zn = 65]
1.28 = 0.08 mol 16 1.30 Number of mol of Zn atoms in 1.3 g Zn = = 0.04 mol 65 Number of oxygen atoms in 1.28 g oxygen is 2 times more than number of zinc atoms in 1.3 g zinc. Number of mol of oxygen atom is 2 times more than zinc atom.
Number of mol of O atoms in 1.28 g SO2 =
CHEMICAL FORMULAE AND CHEMICAL EQUATIONS / FORMULA KIMIA DAN PERSAMAAN KIMIA
Symbol of elements – use capital letters for the first alphabet and use small letters if there is a second alphabet.
1
Simbol unsur – gunakan huruf besar untuk huruf pertama dan huruf kecil jika ada huruf kedua.
Example / Contoh: Potassium / Kalium – K, Calcium / Kalsium – Ca, Iron / Ferum – Fe,
Sodium / Natrium – Na Nitrogen / Nitrogen – N Fluorine / Fluorin – F
Chemical Formula – A set of chemical symbols for atoms of elements in whole numbers representing chemical substances. Formula kimia – Satu set simbol kimia bagi atom-atom unsur dengan gandaan nombor bulat yang mewakili bahan kimia. Chemical substance Bahan kimia
Water Air
Ammonia Ammonia
Propane
m
Notes
Formula kimia
H2O NH3 C3H8
Catatan
2 atoms of H combines with 1 atom of O. 2 atom H bergabung dengan 1 atom O.
3 atoms of H combines with 1 atom of N. 3 atom H bergabung dengan 1 atom N.
3 atoms of C combines with 8 atoms of H. 3 atom C bergabung dengan 8 atom H.
2
Information that can be obtained from the chemical formula / Maklumat yang diperoleh daripada formula kimia: (i) All the elements present in the compound / Jenis unsur yang terdapat dalam sebatian, (ii) Number of atoms of each element in the compound / Bilangan atom setiap unsur yang terdapat dalam sebatian, (iii) Calculation of RMM/RFM of the compound / Pengiraan JMR/JFR bagi sebatian.
3
Two types of chemical formula / Dua jenis formula kimia: (i) Empirical formula / Formula empirik, (ii) Molecular formula / Formula molekul.
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Chemistry Form 4 • MODULE
EMPIRICAL FORMULA / FORMULA EMPIRIK 1 2
A formula that shows the simplest whole number ratio of atoms of each element in a compound. Formula yang menunjukkan nisbah nombor bulat teringkas bagi bilangan atom setiap unsur yang terdapat dalam sebatian. The formula can be determined by calculating the simplest ratio of moles of atoms of each element in the compound. Formula itu boleh ditentukan dengan menghitung nisbah bilangan mol atom bagi setiap unsur yang terdapat dalam sebatian.
3
Experiments to determine empirical formula of metal oxide / Formula empirik bagi oksida logam diperoleh dengan cara: Empirical formula of magnesium oxide
Empirical formula of copper(II) oxide
Formula empirik magnesium oksida
Set-up of apparatus / Susunan radas:
Formula empirik kuprum(II) oksida
Set-up of apparatus / Susunan radas: Copper(II) oxide Kuprum(II) oksida
Magnesium Magnesium
Hydrogen gas Gas hidrogen
Heat
Heat
Panaskan
Panaskan
Reaction occurs / Tindak balas yang berlaku:
Reaction occurs / Tindak balas yang berlaku:
Magnesium dipanaskan dengan kuat di dalam mangkuk pijar untuk bertindak balas dengan oksigen membentuk magnesium oksida.
Gas hidrogen dilalukan melalui kuprum(II) oksida yang dipanaskan. Hidrogen menurunkan kuprum(II) oksida kepada kuprum dan air.
Balanced equation / Persamaan kimia seimbang:
Balanced equation / Persamaan kimia seimbang:
This method can also be used to determine the empirical formulae of reactive metals such as aluminium oxide and zinc oxide.
This method can also be used to determine the empirical formulae of less reactive metals such as lead(II) oxide and tin(II) oxide.
Kaedah ini boleh juga digunakan untuk menentukan formula empirik oksida logam reaktif seperti aluminium oksida dan zink oksida.
Kaedah ini boleh juga digunakan untuk menentukan formula empirik oksida logam kurang reaktif seperti plumbum(II) oksida and stanum(II) oksida.
Magnesium is burnt in a crucble to react with oxygen to form magnesium oxide.
2Mg + O2 → 2MgO
4
Hydrogen gas is passed through heated copper(II) oxide. Hydrogen reduces copper(II) oxide to form copper and water.
CuO + H2 → Cu + H2O
Experiment to Determine Empirical Formula of Magnesium Oxide Eksperimen untuk Menentukan Formula Empirik Magnesium Oksida
In this experiment, magnesium reacts with oxygen in the air to form white fumes, magnesium oxide: Semasa eksperimen ini, magnesium bertindak balas dengan oksigen dalam udara untuk membentuk asap putih, magnesium oksida:
Magnesium + Oxygen → Magnesium oxide Magnesium + Oksigen → Magnesium oksida
Material / Bahan: Magnesium ribbon, sand paper
Apparatus / Radas: Crucible with lid, tongs, Bunsen burner, tripod stand and balance
Set-up of apparatus / Susunan radas:
Magnesium ribbon
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MODULE • Chemistry Form 4
Procedure / Langkah:
crucible
(a) A
Mangkuk pijar
penutup
dengan
pita magnesium
Pita magnesium
coiled
gulung
di
crucible
(d) The
ditimbang.
sand paper
..
loosely and placed in the crucible.
dan diletakkan dalam mangkuk pijar.
magnesium ribbon are weighed again.
together with the lid and
Mangkuk pijar
.
kertas pasir
dibersihkan dengan menggunakan
magnesium ribbon is
(c) The
are weighed.
magnesium ribbon is cleaned with
(b) 10 cm of 10 cm
lid
and its
pita magnesium
bersama dengan penutup dan
ditimbang.
(e) The apparatus is set up as shown in the diagram. Radas disusun seperti dalam gambar rajah.
strongly
(f) The crucible is heated burn
Mangkuk pijar dipanaskan dengan terbakar , mangkuk pijar ditutup dengan
lid
pita magnesium Apabila kuat selama 2 minit lagi.
crucible
, lid and its content are heating
penutup
is removed and the crucible is
dibuka dan mangkuk pijar dipanaskan dengan
weighed again
.
.
ditimbang sekali lagi
cooling
,
suhu bilik
.
repeated
and weighing are
until a
mass is obtained.
pemanasan tetap
penyejukan
,
dan penimbangan
diulang
beberapa kali sehingga jisim
diperoleh.
Observation / Pemerhatian:
Magnesium burns
brightly
Magnesium terbakar dengan
white fumes
to release
terang
membebaskan
and
wasap putih
white solid
is formed. pepejal putih
dan kemudiannya membentuk
.
Inference / Inferens:
Magnesium is a
reactive
metal. reaktif
Magnesium adalah logam yang
Magnesium reacts with
oxygen
Magnesium bertindak balas dengan
.
in the air to form oksigen
magnesium oxide
dalam udara membentuk
.
magnesium oksida
.
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,
, penutup dan kandungannya
constant
lid
lid and its content are allowed to cool down to room temperature .
(k) The process of
m
.
, the
, penutup dan kandungannya dibiarkan sejuk ke
Mangkuk pijar
burning terbakar
berhenti
crucible
Mangkuk pijar
Proses
. Apabila pita magnesium mula
dibuka sekali sekala dengan menggunakan penyepit.
(h) When the magnesium ribbon stops heated strongly for another 2 minutes.
(j) The
tanpa penutup
.
penutup
of the crucible is lifted from time to time using a pair of tongs.
Penutup
(i) The
. When the magnesium starts to
lid
, the crucible is covered with its kuat
(g) The
lid
without its
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Chemistry Form 4 • MODULE
Precaution steps / Langkah berjaga-jaga: Step taken / Langkah yang diambil
Purpose / Tujuan
Magnesium ribbon is cleaned with sand paper . Pita magnesium perlu digosok dengan
kertas pasir
To remove the oxide layer on the surface of the magnesium ribbon.
.
Untuk membuang lapisan oksida pada permukaan magnesium oksida.
The crucible lid is lifted from time to time.
To allow
replaced
from the air to react with magnesium .
Untuk membenarkan oksigen masuk dan bertindak balas dengan magnesium .
Penutup mangkuk pijar dibuka sekali sekala.
The crucible lid then
oxygen
To prevent fumes of magnesium oxide from escaping.
quickly.
Untuk mengelakkan wasap magnesium oksida dari terbebas.
Penutup mangkuk pijar kemudian ditutup semula dengan cepat.
The process of heating , cooling and weighing are To ensure magnesium react completely with repeated until a constant mass is obtained. for magnesium oxide .
Result / Keputusan: Description / Penerangan
Mass (g) / Jisim (g)
Mass of crucible + lid
x
Jisim mangkuk pijar + penutup
Mass of crucible + lid + magnesium
y
Jisim mangkuk pijar + penutup + magnesium
Mass of crucible + lid + magnesium oxide
z
Jisim mangkuk pijar + penutup + magnesium oksida
Calculation / Pengiraan: Element / Unsur
Mg
O
Mass (g) / Jisim (g)
y–x
z–y
Number of mole of atoms / Bilangan mol atom
y–x 24
z–y 16
Simplest ratio of moles / Nisbah mol teringkas
p
q
MgpOq
Empirical formula of magnesium oxide is Mg O
Formula empirik magnesium oksida ialah 5
to
lengkap Untuk memastikan semua magnesium telah bertindak balas oksigen dengan untuk membentuk magnesium oksida .
pemanasan , penyejukan penimbang dan Proses jisim tetap diulang beberapa kali sehingga diperoleh.
oxygen
p
q
. .
Experiment to Determine Empirical Formula of Copper(II) Oxide Eksperimen untuk Menentukan Formula Empirik Kuprum(II) Oksida
Copper(II) Oxide + Hidrogen → Copper + Water Kuprum(II) oksida + Hidrogen → Kuprum + Air
Set-up of apparatus / Susunan radas:
Copper(II) oxide Burning of hydrogen gas Hydrogen gas Combustion tube Heat
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Anhydrous calcium chloride, CaCl2
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MODULE • Chemistry Form 4
Observation / Pemerhatian:
The
black
Warna
colour of copper(II) oxide turns
hitam
brown
perang
kuprum(II) oksida menjadi
.
.
Inference / Inferens:
copper metal
Copper(II) oxide reacts with hydrogen to produce the brown Kuprum(II) oksida bertindak balas dengan hidrogen untuk menghasilkan
.
logam kuprum
yang berwarna perang.
Precaution steps / Langkah berjaga-jaga: Step taken / Langkah yang ambil
Purpose / Tujuan
Hydrogen gas is passed through anhydrous calcium chloride.
hydrogen gas.
Gas hidrogen dialirkan melalui kalsium klorida kontang.
mengering
Kalsium klorida kontang menyerap wap air untuk
Dry hydrogen is passed through the combustion tube for 5 to 10 minutes.
To remove all the
air
gas hidrogen.
in the combustion tube. air explodes when lighted).
(The mixture of hydrogen gas and
kering dialirkan melalui tabung pembakaran Gas hidrogen selama 5 hingga 10 minit.
udara dalam tabung pembakaran. Untuk mengeluarkan semua udara (Campuran hidrogen dan menghasilkan letupan apabila dinyalakan)
If the gas burns quietly without ‘pop’ sound , all the has been removed from the combustion tube.
The gas that comes out from the small hole is collected in the test tube. Then, a lighted wooden splinter is placed
dry
Anhydrous calcium chloride absorb water vapour to
bunyi ‘pop’ Jika gas terbakar tanpa daripada tabung pembakaran.
at mouth of the test tube.
Gas yang keluar daripada lubang kecil dikumpul dalam sebuah tabung uji. Kayu uji menyala di letakkan di mulut tabung uji.
The flow of hydrogen gas must be continuous throughout the experiment.
, semua gas telah
air
dikeluarkan
To prevent hot copper from reacting with oxygen to form copper(II) oxide again.
Gas hidrogen dialirkan secara berterusan sepanjang eksperimen.
Untuk mengelakkan kuprum panas daripada bertindak balas dengan oksigen dan membentuk kuprum(II) oksida .
The process of heating , cooling and weighing are To ensure all copper(II) oxide has changed to copper . Untuk memastikan semua kuprum(II) oksida telah bertukar kepada kuprum . repeated until a constant mass is obtained. pemanasan , penyejukan Proses diulang beberapa kali sehingga jisim
dan tetap
penimbang diperoleh.
Result / Keputusan: Description / Penerangan
Mass (g) / Jisim (g)
Mass of combustion tube + porcelain dish
x
Jisim tabung pembakaran + piring tanah liat
Mass of combustion tube + porcelain dish + copper(II) oxide
y
Jisim tabung pembakaran + piring tanah liat + kuprum(II) oksida
Mass of combustion tube + porcelain dish + copper
z
Jisim tabung pembakaran + piring tanah liat + kuprum
Calculation / Pengiraan: Element / Unsur
Cu
O
Mass (g) / Jisim (g)
z–x
y–z
Number of mole of atoms / Bilangan mol atom
z–x 64
y–z 16
Simplest ratio of moles / Nisbah mol teringkas
p
q
Empirical formula of copper(II) oxide is m
CupOq
. .
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Formula empirik kuprum(II) oksida ialah
CupOq
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Chemistry Form 4 • MODULE
6
Explain why the set-up of apparatus to determine the empirical formula in both the experiments is different. Terangkan mengapa susunan radas untuk menentukan formula empirik dalam kedua-dua eksperimen itu berbeza.
reactive
(a) Magnesium is
magnesium oxide
metal (above hidrogen in reactivity series). Magnesium
reacts
easily to form
.
reaktif Magnesium adalah logam membentuk magnesium oksida .
teroksida
(terletak di atas hidrogen dalam siri kereaktifan. Magnesium mudah
(b) Copper is below hydrogen in the metal reactivity series. Oxygen in copper(II) oxide can be reduced/removed by
hydrogen gas
Kuprum di bawah gas hidrogen 7
to form copper and water. hidrogen
dalam siri kereaktifan. Kuprum(II) okida boleh
diturunkan/disingkirkan
oleh
untuk membentuk kuprum dan air.
To calculate the empirical formula of a compound, use the following table: Untuk menghitung formula empirik suatu sebatian, jadual di bawah boleh digunakan sebagai panduan:
Calculation steps / Langkah pengiraan:
Element / Unsur
(a) Calculate the mass of each element in the compound. Hitungkan jisim setiap unsur dalam sebatian.
Mass of element (g) / Jisim unsur (g)
(b) Convert the mass of each element to number of mole of atom.
Number of mole of atom / Bilangan mol atom
Tukar jisim setiap unsur kepada bilangan mol atom.
(c) Calculate the simplest ratio of moles of atom of the elements.
Simplest ratio of moles / Nisbah mol teringkas
Hitungkan nisbah bilangan mol atom teringkas unsur-unsur tersebut.
EXERCISE / LATIHAN 1
When 11.95 g of metal X oxide is reduced by hydrogen, 10.35 g of metal X is produced. Calculate the empirical formula of metal X oxide. Apabila 11.95 g oksida logam X diturunkan oleh hidrogen, 10.35 g logam terhasil. Hitungkan formula empirik bagi oksida logam X. [RAM / JAR: X = 207, O = 16] X
O
Mass of element (g) / Jisim unsur (g)
10.35
1.6
Number of mole of atoms / Bilangan mol atom
0.05
0.1
Ratio of moles / Nisbah mol
1
2
Simplest ratio of moles / Nisbah mol teringkas
1
2
Element / Unsur
Empirical formula / Formula empirik: 2
XO2
.
A certain compound contains the following composition / Satu sebatian mengandungi komposisi unsur seperti berikut: Na = 15.23%, Br = 52.98%, O = 31.79 % [Relative atomic mass / Jisim atom relatif: O = 16, Na = 23, Br = 80] (Assume that 100 g of substance is used / Anggap 100 g bahan digunakan) Element / Unsur
Na
Br
O
Mass of element (g) / Jisim unsur (g)
15.23
52.98
31.79
Number of mole of atoms / Bilangan mol atom
0.66
0.66
1.99
Ratio of moles / Nisbah mol
1
1
3.01
Simplest ratio of moles / Nisbah mol teringkas
1
1
3
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Empirical formula / Formula empirik:
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MODULE • Chemistry Form 4
2.08 g of element X combines with 4.26 g of element Y to form a compound with formula XY3. Calculate the relative atomic mass of element X. [RAM: Y = 35.5]
3
2.08 g unsur X bergabung dengan 4.26 g unsur Y untuk membentuk sebatian dengan formula XY3 . Hitung jisim atom relatif unsur X. [JAR: Y = 35.5] Element / Unsur Mass of element (g) Jisim unsur (g)
Number of mole of atoms Bilangan mol atom
Simplest ratio of moles Nisbah mol teringkas
X
Y
2.08
4.26
2.08 x
4.26 = 0.12 35.5
1
3
x = relative atomic mass of X Mol X = 1
Mol Y 3 2.08 x 1 = 0.12 3 x = 52
2.07 g of element Z reacts with bromine to form 3.67 g of a compound with empirical formula ZBr2. Calculate the relative atomic mass of element Z. [RAM: Br = 80]
4
2.07 g unsur Z bertindak balas dengan bromin membentuk 3.67 g sebatian dengan formula empirik ZBr2. Hitung jisim atom relatif bagi unsur Z. [JAR: Br = 80] Element / Unsur Mass of element (g) Jisim unsur (g)
Number of mole of atoms Bilangan mol atom
Simplest ratio of moles Nisbah mol teringkas
Z
Br
z = relative atomic mass of Z
2.07
1.6
Mol Z
2.07 z
1.6 = 0.02 80
1
2
= 1 Mol Br 2 2.08 z 1 = 2 0.02 z = 207
The statement below is about compound J / Pernyataan berikut adalah mengenai sebatian J.
5
• It is black solid / Merupakan pepejal hitam. • Contains 12.8 g copper and 0.2 mol of oxygen / Mengandungi 12.8 g kuprum dan 0.2 mol oksigen. [Relative atomic mass / Jisim atom relatif : Cu = 64] (a) What is meant by empirical formula / Apakah maksud formula empirik? A formula that shows the simplest whole number ratio of atoms of each element in a compound. (b) (i)
(ii)
Calculate the number of mol of copper atom / Hitung bilangan mol atom kuprum. 12.8 = 0.2 mol 64 What is the empirical formula of compound J / Apakah formula empirik sebatian J ? 0.2 mol Cu : 0.2 mol O. 1 mol Cu : 1 mol O. Empirical formula of Compound J is CuO.
(c) Compound J reacts completely with hydrogen to produce copper and compound Q. Sebatian J bertindak balas lengkap dengan hidrogen menghasilkan kuprum dan sebatian Q.
(i)
State one observation for the reaction / Nyatakan satu pemerhatian daripada tindak balas tersebut. Black solid change to brown
(ii) Name two the substances that can be used to prepare hydrogen gas. Namakan dua bahan yang digunakan untuk menyediakan gas hidrogen.
Zinc/magnesium and hydrochloric acid/nitric acid/sulphuric acid.
(iii) Name compound Q / Nama sebatian Q. Water
(iv) Write a balanced equation for the reaction. Tuliskan persamaan kimia yang seimbang bagi tindak balas tersebut.
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Chemistry Form 4 • MODULE
(d) Draw a labelled diagram of the set-up of apparatus for the experiment. Lukiskan gambar rajah berlabel susunan radas bagi tindak balas tersebut.
Gas hidrogen
Compound J
Heat (e) (i)
Why is hydrogen gas passed through the combustion tube after heating has stpopped? Mengapakah gas hidrogen dilalukan melalui tiub pembakaran selepas pemanasan dihentikan?
To avoid copper produced react with oxygen to form copper(II) oxide.
(ii) State how to determine that the reaction between compound J and hydrogen has completed. Nyatakan bagaimana menentukan tindak balas antara sebatian J dengan hidrogen telah lengkap.
By repeating the process of heating, cooling and weighing until constant mass is obtained. (f) (i)
Can the empirical formula of magnesium oxide be determined by the same method? Explain your answer. Bolehkah formula empirik bagi magnesium oksida ditentukan dengan cara yang sama? Jelaskan jawapan anda.
Cannot. Magnesium is more reactive than hydrogen. Hydrogen cannot reduce magnesium oxide to form magnesium.
(ii) Magnesium can reduce copper oxide to copper. Explain why the empirical formula of the copper oxide cannot be determined by heating the mixture of copper oxide and magnesium powder. Magnesium boleh menurunkan kuprum oksida kepada kuprum. Terangkan mengapa formula empirik kuprum oksida tidak boleh ditentukan dengan pemanasan campuran kuprum oksida dengan serbuk magnesium.
Magnesium oxide and copper produced are in solid form, copper cannot be separated from magnesium oxide. The mass of copper cannot be weighed.
MOLECULAR FORMULA / FORMULA MOLEKUL 1
Molecular formula of a compound shows the actual number of atoms of each element that are present in a molecule of the compound. Formula molekul suatu sebatian menunjukkan bilangan sebenar atom bagi setiap unsur yang terdapat dalam satu molekul sebatian.
Molecular Formula = (empirical formula)n, where n is a integer. Formula molekul = (Formula empirik)n, di mana n adalah integer. 2
Example / Contoh: Compound
Molecular formula
Empirical formula
Value of n
Water / Air
H2O
H2O
1
Carbon dioxide / Karbon dioksida
CO2
CO2
1
H2SO4
H2SO4
1
Ethene / Etena
C2H4
CH2
2
Benzene / Benzena
C6H6
CH
6
Glucose / Glukosa
C6H12O6
CH2O
6
Sebatian
Sulphuric acid / Asid sulfurik
Formula molekul
Formula empirik
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The molecular formula and the empirical formula of a compound may be the same if the value of n = 1 but different if the value is n > 1. Formula molekul dan formula empirik suatu sebatian akan sama sekiranya nilai n = 1 tetapi akan berbeza sekiranya nilai n > 1.
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MODULE • Chemistry Form 4
EXERCISE / LATIHAN
The empirical formula of compound X is CH2 and relative molecular mass is 56. Determine the molecular formula of compound X. [Relative atomic mass: H = 1; C = 12]
1
Formula empirik sebatian X adalah CH2 dan JMR adalah 56. Tentukan formula molekul sebatian X. [Jisim atom relatif: H = 1; C = 12]
(12 + 2)n = 56 56 n = = 4 14 Molecular formula = (CH2)4 = C4H8 2.58 g of a hydrocarbon contains 2.16 g of carbon. The relative molecular mass of the hydrocarbon is 86.
2
2.58 g suatu hidrokarbon mengandungi 2.16 g karbon. Jisim molekul relatif bagi hidrokarbon ini ialah 86. [Relative atomic mass / Jisim atom relatif : H = 1; C = 12] (i) Calculate the empirical formula of the hydrocarbon / Hitungkan formula empirik bagi hidrokarbon ini. Element
C
H
Mass of element (g)
2.16
0.42
Number of mole of atoms
0.18
0.42
Ratio of moles
1
2 1 = 7 3 3
Simplest ratio of moles
3
7
Empirical formula = C3H7
(ii) Determine the molecular formula of the hydrocarbon / Tentukan formula molekul hidrokarbon tersebut. (12 × 3 + 7 × 1)n = 86 86 n = = 2 43 Molecular formula = (C3H7)2 = C6H14 The diagram below shows the structural formula for benzene molecule.
3
Rajah di bawah menujukkan formula struktur bagi benzena. H H
C
H
C
C C
C
H
C
H
H
(a) Name the element that make up benzene / Namakan unsur yang membentuk benzena. Carbon and hydrogen (b) What are the molecular formula and empirical formula for benzene? Apakah formula molekul dan formula empirik bagi benzena?
Molecular formula / Formula molekul: C6H6 Empirical formula / Formula empirik: CH
(c) Compare and contrast the molecular formula and empirical formula for benzene. Banding dan bezakan formula molekul dan formula empirik bagi benzena.
• Both empirical formula and molecular formula shows benzene is made up of elements. Kedua-dua fomula molekul dan formula empirik menunjukkan benzena terdiri dari unsur
actual
carbon
and hydrogen
karbon
dan
hidrogen
.
number of atoms and hydrogen atoms in benzene • Molecular formula shows the molecule . Each benzene molecule consists of 6 carbon atoms and 6 hydrogen atoms.
m
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carbon
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Chemistry Form 4 • MODULE
• Empirical formula shows the simplest ratio of number carbon atoms to hydrogen atoms, the simplest carbon hydrogen 1 : 1 ratio of number of atoms to atoms in benzene is . Formula empirik benzena menunjukkan
nisbah paling ringkas
Nisbah paling ringkas bilangan atom
karbon
kepada
hidrogen
karbon bilangan atoms kepada atom hidrogen 1 : 1 adalah .
.
PERCENTAGE COMPOSITION BY MASS OF AN ELEMENT IN A COMPOUND PERATUS KOMPOSISI UNSUR MENGIKUT JISIM DALAM SEBATIAN
Total RAM of the element in the compound × 100% 1
% composition by mass of an element = % komposisi unsur mengikut jisim
2
Jumlah JAR unsur dalam suatu sebatian × 100%
RMM/RFM of compound/JMR/JFR sebatian
Example / Contoh: Calculate the percentage composition by mass of nitrogen in the following compounds: Hitungkan peratusan nitrogen mengikut jisim dalam sebatian berikut: [Relative atomic mass / Jisim atom relatif : N = 14, H = 1, O = 16, S = 32, K = 39]
(i) (NH4)2SO4 2 × 14 × 100% 132 = 21.2%
%N =
(ii) KNO3
14 × 100% 101 = 13.9%
%N =
CHEMICAL FORMULA FOR IONIC COMPOUNDS / FORMULA KIMIA BAGI SEBATIAN ION 1
Chemical formula of an ionic compound comprising of the ions Xm+ and Yn– is by exchanging the charges on each ion. The formula obtained will be XmYn.
Formula kimia sebatian ion yang mengandungi ion X m+ dan Y n– boleh diperoleh melalui pertukaran bilangan cas setiap ion. Formula yang diperoleh ialah XnYm. 2
Example / Contoh: (i) Sodium oxide / Natrium oksida Ion / Ion
Na+
O2–
+1
–2
Exchange of charges / Pertukaran bilangan cas
2
1
Smallest ratio / Nisbah teringkas
2
1
2 Na+
O2–
Charges / Bilangan cas
Number of combining ions / Bilangan ion yang bergabung Formula / Formula
(ii) Copper(II) nitrate / Kuprum(II) nitrat Cu2+ +2
1 2 (Ratio / Nisbah) ⇒ Cu(NO3)2
(iii) Zinc oxide / Zink oksida Zn2+ +2
O2– –2
2
2
1 ⇒ ZnO
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NO3– –1
Na2O
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CuO Copper(II) oxide
CaO Calcium oxide
Ag2O Silver oxide
Na2O Sodium oxide
K2O Potassium oxide
Ion aluminium
Al 3+ Aluminium ion
Ion plumbum(II)
Pb2+ Lead(II) ion
Ion zink
Zn2+ Zinc ion
PbCO3 Lead(II) carbonate
ZnCO3 Zinc carbonate
MgCO3 Magnesium carbonate
CuCO3 Copper(II) carbonate
PbSO4 Lead(II) sulphate
ZnSO4 Zinc sulphate
MgSO4 Magnesium sulphate
CuSO4 Copper(II) sulphate
CaSO4 Calcium sulphate
(NH4)2SO4 Ammonium sulphate
(NH4)2CO3 Ammonium carbonate
H2SO4 Sulphuric acid
Na2SO4 Sodium sulphate
Ag2SO4 Silver sulphate
CaCO3 Calcium carbonate
Ion klorida
Cl–, Chloride ion Ion bromida
Br–, Bromide ion
CaBr2 Calcium bromide
NH4Br Ammonium bromide
AgBr Silver bromide
HBr Hydrobromic acid
NaBr Sodium bromide
AlCl3 Aluminium chloride
PbCl2 Lead(II) chloride
ZnCl2 Zinc chloride
MgCl2 Magnesium chloride
PbI2 Lead(II) iodide
ZnI2 Zinc iodide
Ion nitrat
NO3–, Nitrate ion
Ca(NO3 )2 Calcium nitrate
NH4NO3 Ammonium nitrate
AgNO3 Silver nitrate
HNO3 Nitric acid
NaNO3 Sodium nitrate
Pb(OH)2 Lead(II) hydroxide
Zn(OH)2 Zinc hydroxide
Al(NO3)3 Aluminium nirate
Pb(NO3 )2 Lead(II) nitrate
Zn(NO3 )2 Zinc nitrate
Mg(NO3 )2 Magnesium nitrate
Cu(OH)2 Cu(NO3 )2 Copper(II) hydroxide Copper(II) nitrate
Ca(OH)2 Calcium hydroxide
AgOH Silver hydroxide
NaOH Sodium hydroxide
KOH KNO3 Potassium hydroxide Potassium nitrate
Ion hidroksida
OH–, Hydroxide ion
Mg(OH)2 MgI2 Magnesium Magnesium iodide hydroxide
CuI2 Copper(II) iodide
CaI2 Calcium iodide
NH4I Ammonium iodide
AgI Silver iodide
HI Hydroiodic acid
NaI Sodium iodide
KI Potassium iodide
Ion iodida
I–, Iodide ion
Al(OH)3 AlBr3 AlI3 Aluminium Aluminium bromide Aluminium iodide hydroxide
PbBr2 Lead(II) bromide
ZnBr2 Zinc bromide
MgBr2 Magnesium bromide
CuCl2 CuBr2 Copper(II) chloride Copper(II) bromide
CaCl2 Calcium chloride
NH4Cl Ammonium chloride
AgCl Silver chloride
HCl Hydrocloric acid
NaCl Sodium chloride
K2SO4 KCl KBr Potassium sulphate Potassium chloride Potassium bromide
Ion sulfat
SO42–, Sulphate ion
Ag2CO3 Silver carbonate
H2CO3 Carbonic acid
Na2CO3 Sodium carbonate
K2CO3 Potassium carbonate
Ion karbonat
CO32–, Carbonat ion
Al2(SO4 )3 Al2O3 Al2(CO3 )3 Aluminium Aluminium oxide Aluminium carbonate sulphate
PbO Lead(II) oxide
ZnO Zinc oxide
MgO Mg2+ Magnesium ion Magnesium Ion magnesium oxide
Ion kuprum(II)
Cu2+ Copper(II) ion
Ion kalsium
Ca2+ Calcium ion
Ion ammonium
NH4 + Ammonium ion
Ion argentum
Ag+ Silver ion
Ion hidrogen
H+ Hydrogen ion
Ion natrium
Na+ Sodium ion
Ion kalium
K+ Potassium ion
Ion oksida
O2–, Oxide ion
Aktiviti 1: TULIS FORMULA KIMIA DAN NAMA BAGI BAHAN KIMIA BERIKUT
ACTIVITY 1: WRITE THE CHEMICAL FORMULAE AND NAMES OF THE FOLLOWING COMMON COMPOUNDS
MODULE • Chemistry Form 4
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Ion aluminium
Aluminium ion
Ion plumbum(II)
Lead(II) ion
Ion zink
Zinc ion
Ion magnesium
Magnesium ion
Ion kuprum(II)
Copper(II) ion
Ion kalsium
Calcium ion
Ion ammonium
Ammonium ion
Ion argentum
Silver ion
Ion hidrogen
Hydrogen ion
Ion natrium
Sodium ion
Ion kalium
Potassium ion
Al2O3
PbO
ZnO
MgO
CuO
CaO
Ag2O
Na2O
K2O
Ion oksida
Oxide ion
Al2(CO3)3
PbCO3
ZnCO3
MgCO3
CuCO3
CaCO3
(NH4 )2CO3
Ag2CO3
H2CO3
Na2CO3
K2CO3
Ion karbonat
Carbonat ion
Al2(SO4 )3
PbSO4
ZnSO4
MgSO4
CuSO4
CaSO4
(NH4 )2SO4
Ag2SO4
H2SO4
Na2SO4
K2SO4
Ion sulfat
Sulphate ion
AlCl3
PbCl2
ZnCl2
MgCl2
CuCl2
CaCl2
NH4Cl
AgCl
HCl
NaCl
KCl
Ion klorida
Chloride ion
AlBr3
PbBr2
ZnBr2
MgBr2
CuBr2
CaBr2
NH4 Br
AgBr
HBr
NaBr
KBr
Ion bromida
Bromide ion
AlI3
PbI2
ZnI2
MgI2
CuI2
CaI2
NH4 I
AgI
HI
NaI
KI
Ion iodida
Iodide ion
Al(OH)3
Pb(OH)2
Zn(OH)2
Mg(OH)2
Cu(OH)2
Ca(OH)2
AgOH
NaOH
KOH
Ion hidroksida
Hydroxide ion
AKTIVITI 2: TANPA MERUJUK KEPADA JADUAL AKTIVITI 1, TULISKAN FORMULA KIMIA BAGI SEBATIAN BERIKUT
Al(NO3 )3
Pb(NO3 )2
Zn(NO3 )2
Mg(NO3 )2
Cu(NO3 )2
Ca(NO3 )2
NH4 NO3
AgNO3
HNO3
NaNO3
KNO3
Ion nitrat
Nitrate ion
ACTIVITY 2: WITHOUT REFERRING TO THE TABLE IN ACTIVITY 1, WRITE THE CHEMICAL FORMULAE OF THE FOLLOWING COMPOUNDS
Chemistry Form 4 • MODULE
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MODULE • Chemistry Form 4
ACTIVITY 3: WRITE THE CHEMICAL FORMULAE AND TYPE OF PARTICLES FOR THE FOLLOWING ELEMENT/COMPOUND AKTIVITI 3: TULIS FORMULA KIMIA DAN JENIS ZARAH UNTUK UNSUR/SEBATIAN BERIKUT
Compound / Element Sebatian/Unsur
Sodium sulphate Natrium sulfat
Ammonium carbonate Ammonium karbonat
Magnesium nitrate Magnesium nitrat
Hyrochloric acid Asid hidroklorik
Potassium oxide Kalium oksida
Magnesium oxide Magnesium oksida
Lead(II) carbonate Plumbum(II) karbonat
Iron(III) sulphate Ferum(III) sulfat
Magnesium chloride Magnesium klorida
Zinc sulphate Zink sulfat
Silver nitrate Argentum nitrat
Ammonium sulphate Ammonium sulfat
Zinc oxide Zink oksida
Nitric acid Asid nitrik
Ammonia gas Gas ammonia
Magnesium Magnesium
Zinc Zink
Copper(II) sulphate Kuprum(II) sulfat
Iodine Iodin
Chlorine m
Type of particles
Na2SO4
Ion
(NH4 )2CO3
Ion
Mg(NO3 )2
Ion
HCl
Ion
K2O
Ion
MgO
Ion
PbCO3
Ion
Fe2(SO4)3
Ion
MgCl2
Ion
ZnSO4
Ion
AgNO3
Ion
(NH4 )2SO4
Ion
ZnO
Ion
HNO3
Ion
NH3
Molecule
Mg
Atom
Zn
Atom
CuSO4
Ion
I2
Molecule
Cl2
Molecule
Formula
Jenis zarah
Compound / Element Sebatian/Unsur
Zinc carbonate Zink karbonat
Ammonium carbonate Ammonium karbonat
Silver chloride Argentum klorida
Sulphuric acid Asid sulfurik
Copper(II) nitrate Kuprum(II) nitrat
Hydrogen gas Gas hidrogen
Carbon dioxide gas Gas karbon dioksida
Oxygen gas Gas oksigen
Aluminium sulphate Aluminium sulfat
Lead(II) chloride Plumbun(II) klorida
Potassium iodide Kalium iodida
Copper(II) carbonate Kuprum(II) karbonat
Potasium carbonate Kalium karbonat
Sodium hydroxide Natrium hidroksida
Aqueous ammonia Ammonia akueus
Ammonium chloride Ammonium klorida
Nitrogen dioxide gas Gas nitrogen dioksida
Sodium chloride Natrium klorida
Silver Argentum
Bromine Bromin
Formula
Type of particles
ZnCO3
Ion
(NH4 )2CO3
Ion
AgCl
Ion
H2SO4
Ion
Cu(NO3 )2
Ion
H2
Molecule
CO2
Molecule
O2
Molecule
Al2(SO4 )3
Ion
PbCl2
Ion
KI
Ion
CuCO3
Ion
K2CO3
Ion
NaOH
Ion
NH3(aq)
Ion and molecule
NH4Cl
Ion
NO2
Molecule
NaCl
Ion
Ag
Atom
Br2
Molecule
Formula
Jenis zarah
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Chemistry Form 4 • MODULE
CHEMICAL EQUATIONS / PERSAMAAN KIMIA 1
Two types of equation / Dua jenis persamaan: • Equation in words / Persamaan perkataan – using names of reactants and products / menggunakan nama bahan tindak balas dan hasil tindak balas; • Equation using symbols / Persamaan menggunakan simbol – reactants and products are represented by chemical formulae and have certain meanings menggunakan formula kimia untuk mewakili bahan tindak balas dan hasil tindak balas serta menggunakan pelbagai jenis simbol yang membawa makna tertentu. Symbol / Simbol +
2
Meaning / Maksud
Symbol / Simbol
Meaning / Maksud
Separating 2 reactants / products
(g)
Gaseous state
Mengasingkan 2 bahan / hasil
(g)
Keadaan gas
Produces
(aq)
Aqueous state
Menghasilkan
(ak)
Keadaan akueus
Reversible reaction
Gas released
Tindak balas berbalik
Gas terbebas
(s)
Solid state
Precipitation
(p)
Keadaan pepejal
Bahan termendap
(l)
Liquid state
(ce)
Keadaan cecair
∆
Heating / Heat energy is given Pemanasan / Haba dibekalkan
Information obtained from chemical equation using symbols / Maklumat yang diperoleh daripada persamaan kimia bersimbol: (a) Qualitative aspect / Aspek kualitatif : type of reactants and products involved in the chemical reaction and the state of each reactant and product. jenis bahan / hasil tindak balas yang terlibat dalam tindak balas dan keadaan fizikal bagi setiap bahan / hasil tindak balas. (b) Quantitative aspect / Aspek kuantitatif : number of moles of reactants and products involved in the chemical reaction
that is the coeffficients involved in a balanced equation of the formulae of reactants and products. bilangan mol yang bertindak balas dan hasil tindak balas yang terbentuk iaitu pekali bagi setiap formula bahan dan hasil tindak balas.
Example / Contoh:
Zn (s) + 2HCl (aq) ZnCl2 (aq) + H2 (g) Zn (p) + 2HCl (ak)
ZnCl2 (ak) + H2 (g)
1 mol 2 mol 1 mol 1 mol Interpretation / Tafsiran: 1 mol of zinc reacts with 2 mol of hydrochloric acid to produce 1 mol of zinc chloride and 1 mol of hydrogen. 1 mol zink bertindak balas dengan 2 mol asid hidroklorik menghasilkan 1 mol zink klorida dan 1 mol hidrogen. 3
Writing balanced chemical equations / Menulis persamaan kimia seimbang:
Step 1 / Langkah 1 : Write the correct chemical formulae for each reactant and product. Tulis formula kimia bagi setiap bahan dan hasil tindak balas.
Step 2 / Langkah 2 : Detemine the number of atoms for each element / Tentukan bilangan atom setiap unsur. Step 3 / Langkah 3 : Balance the number of atoms for each element by adjusting the coefficients in front of the chemical formulae.
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Imbangkan bilangan atom setiap jenis unsur dengan menambahkan pekali di hadapan setiap formula kimia.
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MODULE • Chemistry Form 4
EXERCISE / LATIHAN Write a balanced chemical equation for each of the following reactions: Tulis persamaan kimia seimbang bagi setiap tindak balas yang berikut:
Zinc carbonate Zinc oxide + Carbon dioxide / Zink karbonat
1
ZnCO3
Zink oksida + Karbon dioksida
ZnO + CO2
Sulphuric acid + Sodium hydroxide Sodium sulphate + Water / Asid sulfurik + Natrium hidroksida
2
H2SO4 + 2NaOH
Natrium sulfat + Air
Na2SO4 + 2H2O
Silver nitrate + Sodium chloride Silver chloride + Sodium nitrate
3
Argentum nitrat + Natrium klorida Argentum klorida + Natrium nitrat AgNO3 + NaCl AgCl + NaNO3
Copper(II) oxide + Hydrochloric acid Copper(II) chloride + Water
4
Kuprum(II) oksida + Asid hidroklorik Kuprum(II) klorida + Air CuO + 2HCl CuCl2 + H2O
Magnesium + Oxygen Magnesium oxide / Magnesium + Oksigen
5
2Mg + O2
2MgO
Sodium + Water Sodium hydroxide + Hydrogen / Natrium + Air
6
Magnesium oksida
2Na + 2H2O
Natrium hidroksida + Hidrogen
2NaOH + H2
Potassium oxide + Water Potassium hydroxide / Kalium oksida + Air
7
K 2O + H 2O
2KOH
Zinc oxide + Nitric acid Zinc nitrate + Water / Zink oksida + Asid nitrik
8
Kalium hidroksida
ZnO + 2HNO3
Zink nitrat + Air
Zn(NO3 )2 + H2O
Lead(II) nitrate Lead(II) oxide + Nitrogen dioxide + Oxygen
9
Plumbum(II) nitrat Plumbum (II) oksida + Nitrogen dioksida + Oksigen 2Pb(NO3 )2 2PbO + 4NO2 + O2 10 Aluminium nitrate Aluminium oxide + Nitrogen dioxide + Oxygen Aluminium nitrat Aluminium oksida + Nitrogen dioksida + Oksigen 4Al(NO3 )3 2Al2O3 + 12NO2 + 3O2
NUMERICAL PROBLEMS INVOLVING CHEMICAL EQUATIONS / PENGHITUNGAN BERKAITAN PERSAMAAN KIMIA Calculation steps / Langkah perhitungan: S1 / L1 : Write a balanced equation / Tulis persamaan kimia seimbang. S2 / L2 : Write the information from the question above the equation / Tulis maklumat daripada soalan di atas persamaan. S3 / L3 : Write the information from the chemical equation below the equation (information about the number of moles of
reactants/products). Tulis maklumat daripada persamaan kimia di bawah persamaan (Maklumat perhubungan bilangan mol bahan/hasil tindak balas terlibat).
S4 / L4 : Change the information in S2 into moles by using the method shown in the chart below. Tukarkan maklumat L2 kepada mol menggunakan carta di bawah. S5 / L5 : Use the relationship between number of moles of substance involved in S3 to find the answer. Gunakan perhubungan bilangan mol bahan terlibat dalam L3 untuk mencari jawapan. S6 / L6 : Change the information to the unit required using the chart below. Tukar maklumat kepada unit yang dikehendaki dengan menggunakan carta di bawah.
Mass (g)
m
× (RAM/FRM/RMM) g mol–1
No. of moles (n) Bilangan mol (n)
× 24 dm3 mol–1 / 22.4 dm3 mol–1 ÷ 24 dm3 mol–1 / 22.4 dm3 mol–1
Volume of gas (dm3) Isipadu gas (dm3)
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Chemistry Form 4 • MODULE
EXERCISE / LATIHAN 1
The equation shows the reaction between zinc and hydrochloric acid. Persamaan menunjukkan tindak balas antara zink dengan asid hidroklorik.
Zn + 2HCl
ZnCl2 + H2
Calculate the mass of zinc required to react with excess hydrochloric acid to produce 6 dm3 of hydrogen gas at room conditions. [Relative atomic mass: Zn = 65, Cl = 35.5, 1 mole of gas occupies 24 dm3 at room conditions] Hitungkan jisim zink yang perlu ditindakbalaskan dengan asid hidroklorik berlebihan untuk menghasilkan 6 dm3 gas hidrogen pada keadaan bilik. [Jisim atom relatif: Zn = 65, Cl = 35.5, 1 mol gas menempati 24 dm3 pada suhu bilik]
Mol of H2 =
6 dm3 = 0.25 mol 24 dm3 mol–1
From the equation, 1 mol of H2 : 1 mol of Zn 0.25 mol of H2 : 0.25 mol of Zn Mass of Zn = 0.25 × 65 = 16.2 g
2
The equation shows the reaction between potassium and oxygen. Persamaan berikut menunjukkan tindak balas antara kalium dengan oksigen.
4K + O2
2K2O
Calculate the mass of potassium required to produce 23.5 g of potassium oxide. [Relative atomic mass: K = 39, O = 16] Hitungkan jisim kalium yang diperlukan untuk menghasilkan 23.5 g kalium oksida. [Jisim atom relatif: K = 39, O = 16]
Mol of K2O =
23.5 23.5 = = 0.25 mol (2 × 39 + 16) 94
From the equation, 2 mol of K2O : 4 mol of K 0.25 mol of K2O : 0.5 mol of K Mass of K = 0.5 mol × 39 g mol–1 = 19.5 g
3
The equation shows the decomposition of hydrogen peroxide. Persamaan menunjukkan penguraian hidrogen peroksida.
H2O2
H2O + O2
Balance the equation above. Calculate the number of moles of H2O2 that decomposes if 11.2 dm3 oxygen gas is collected at STP. [Relative Atomic mass: H = 1, O = 16, molar volume of gas = 22.4 dm3 mol–1 at STP] Seimbangkan persamaan di atas. Hitung bilangan mol H2O2 yang telah terurai sekiranya 11.2 dm3 gas oksigen dikumpulkan pada STP. [Jisim atom relatif: H = 1, O = 16, isi padu molar gas = 22.4 dm3 mol–1 pada STP]
Mol of O2 =
11.2 dm3 = 0.5 mol 22.4 dm3 mol–1
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From the equation, 1 mol of O2 : 2 mol of H2O2 0.5 mol of O2 : 1.0 mol of H2O2
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MODULE • Chemistry Form 4
8.0 g of copper(II) oxide powder is added to excess dilute nitric acid and heated. Calculate the mass of copper(II) nitrate produced. [Relative atomic mass: N = 14, O = 16, Cu = 64]
4
8.0 g serbuk kuprum(II) oksida dicampurkan kepada asid nitrik cair yang berlebihan dan dihangatkan. Hitungkan jisim kuprum(II) nitrat yang terhasil. [Jisim atom relatif: N = 14, O = 16, Cu = 64]
CuO + 2HNO3 Cu(NO3 )2 + H2O Mol of CuO =
8 g = 0.1 mol (64 + 16)g mol–1
From the equation, 1 mol of CuO : 1 mol of Cu(NO3)2 0.1 of CuO : 0.1 mol of Cu(NO3)2 Mass of Cu(NO3)2 = 0.1 mol × 188 g mol–1 = 18.8 g
1.3 g of zinc reacts with excess dilute sulphuric acid. The products are zinc sulphate and hydrogen. Calculate the volume of hidrogen gas released at STP. [Relative atomic mass: Zn = 65, 1 mol of gas occupies 22.4 dm3 mol–1at STP]
5
1.3 g zink bertindak balas dengan asid sulfurik cair yang berlebihan. Hasil tindak balas adalah zink sulfat dan hidrogen. Hitungkan isi padu hidrogen yang terbebas pada STP. [Jisim atom relatif: Zn = 65, isipadu molar gas = 22.4 dm3 mol–1 pada STP]
Answer/Jawapan:
448 cm3
0.46 g of sodium burns completely in chlorine gas at room conditions to produce sodium chloride. Calculate the volume of chlorine gas that has reacted. [Relative atomic mass: Na = 23, Molar volume of gas = 24 dm3 mol–1 at room conditions]
6
0.46 g natrium terbakar lengkap dalam gas klorin pada keadaan bilik menghasilkan natrium klorida. Hitungkan isi padu klorin yang diperlukan untuk bertindak balas lengkap. [Jisim atom relatif: Na = 23, isi padu molar gas = 24 dm3 mol–1 pada keadaan bilik]
Answer/Jawapan:
0.24 dm3
The equation shows the combustion of propane gas.
7
Persamaan menunjukkan pembakaran gas propana.
C3H8 + 5O2
3CO2 + 4H2O
720 cm3 of propane gas (C3H8) at room conditions burns in excess oxygen. Calculate the mass of carbon dioxide formed. [Relative atomic mass: C = 12, O = 16, Molar volume of gas = 22.4 dm3 mol–1 at room conditions] 720 cm3 gas propana (C3H8) pada keadaan bilik terbakar dalam oksigen berlebihan. Hitungkan jisim karbon dioksida yang terbentuk. [Jisim atom relatif: C = 12, O = 16, isi padu molar gas = 24 dm3 mol–1 pada keadaan bilik]
3.96 g
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Chemistry Form 4 • MODULE
Objective Questions / Soalan Objektif 1
2
The mass of one atom of element Y is two times more than an atom of oxygen. What is the relative atomic mass of element Y? [Relative atomic mass: O = 16] Jisim satu atom unsur Y adalah dua kali lebih daripada satu atom oksigen. Apakah jisim atom relatif bagi unsur Y? [Jisim atom relatif: O = 16] A 12 B 24 C 32 D 36
5
Jadual berikut menunujukkan jisim atom relatif bagi neon, karbon, oksigen dan kalsium. Element/Unsur Relative atomic mass/Jisim atom relatif
The chemical formula for butane is C4H10. Which of the following statements are true about butane? [Relative atomic mass: H = 1, C =12 and O =16, Avogadro Constant = 6 × 1023 mol–1]
Formula empirik butana ialah CH2.
III 1 mol of butane contains a total of 8.4 × 1024 atoms. 6
A I and II only
II, III and IV only
II dan III sahaja
D I, II, III and IV I, II, III dan IV
7
A bottle contains 3.01 × 1023 of gas particles. What is the number of moles of the gas in the bottle?
4
C 3.0 mol D 6.0 mol
16 g oksigen mengandungi 6.02 × 1023 molekul oksigen
Mass of one oxygen atom is 16 times bigger than one carbon atom
A bulb is filled with 1 800 cm3 of argon gas at room conditions. What is the number of argon atom in the bulb? [Molar volume of gas = 24 dm3 mol–1 at room conditions, Avogadro constant = 6.02 × 1023 mol–1]
8
Antara gas berikut, yang manakah mengandungi 0.4 mol atom pada suhu dan tekanan bilik? [Isi padu molar gas = 24 dm3 mol–1 pada suhu dan tekanan bilik]
C D
6.02 × 1023 3.01 × 1023
5 g of element X reacted with 8 g of element Y to form a compound with the formula XY2. What is the relative atomic mass of element X? [Relative atomic mass: Y = 80] 5 g unsur X bertindak balas dengan 8 g unsur Y membentuk sebatian dengan formula XY2. Apakah jisim atom relatif unsur X? [Jisim atom relatif: Y = 80]
A 25 B 40
C 50 D 100
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C 4.8 dm3 CO2 D 4.8 dm3 NH3
C 8.03 × 1022 D 8.03 × 1021
What is the number of hydrogen atom in 0.1 mol of water? [Avogadro constant: 6.02 × 1023 mol–1] A 6.02 × 1022 B 60.2 × 1023
Which of the following gases contains 0.4 mol of atoms at room temperature and pressure? [Molar volume of gas = 24 dm3 mol–1 at room temperature and pressure]
A 4.8 dm3 Ne B 4.8 dm3 O2
40
Berapakah bilangan atom oksigen dalam 0.1 mol air? [Pemalar Avogadro = 6.02 × 1023 mol–1]
Sebuah botol mengandungi 3.01 × 1023 zarah gas. Berapakah bilangan mol zarah gas dalam botol itu?
A 0.5 mol B 1.0 mol
Calcium / Kalsium
A 4.515 × 1022 B 4.515 × 1023
II, III dan IV sahaja
3
16
Sebuah belon diisi dengan 1 800 cm3 gas argon pada keadaan bilik. Berapakah bilangan atom argon dalam belon itu? [Isipadu molar gas = 24 dm3 mol–1 pada keadaan bilik, Pemalar Avogadro = 6.02 × 1023 mol–1]
I dan II sahaja
C
Oxygen / Oksigen
Jisim satu atom oksigen adalah 16 kali lebih besar daripada satu atom karbon
Satu molekul butana mempunyai jisim 84 kali lebih daripada jisim satu atom hidrogen.
II and III only
12
D
Setiap molekul butana terdiri dari 4 atom karbon dan 10 atom hidrogen.
B
Carbon / Karbon
molecule
II Each butane molecule is made up of 4 carbon atoms and 10 hydrogen atoms.
IV One butane molecule has a mass of 84 times higher than the mass of 1 hydrogen atom.
20
Antara pernyataan berikut, yang manakah adalah benar? [Pemalar Avogadro = 6.02 × 1023 mol–1] A Mass of one calcium atom is 40 g Jisim satu atom kalsium ialah 40 g B Mass of 1 mol of neon is 20 g Jisim 1 mol neon ialah 20 g C 16 g of oxygen contains 6.02 × 1023 oxygen
The empirical formula for butane is CH2.
Jumlah bilangan atom dalam 1 mol butana adalah 8.4 × 1024.
Neon / Neon
Which of the following statements is true? [Avogadro constant = 6.0 × 1023 mol–1]
Formula kimia bagi butana ialah C4H10. Antara pernyataan berikut, yang manakah adalah benar tentang butana? [Jisim atom relatif: H = 1, C = 12 dan O = 16, Pemalar Avogadro = 6 × 1023 mol–1]
I
The table below shows the relative atomic mass of neon, carbon, oxygen and calcium.
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MODULE • Chemistry Form 4
9
The diagram below shows the set-up of apparatus to determine the empirical formula of an oxide metal X. Rajah di bawah menunjukkan susunan radas bagi menentukan formula empirik oksida logam X.
What is the number of oxygen molecules is produced when 7.4 g magnesium nitrate decomposed when heated. [Relative formula mass of Mg(NO3)2 = 148; Avogadro constant = 6.02 × 1023 mol–1]
Logam X
Heat Panaskan
Which of the following is metal X? Antara berikut, yang manakah mungkin bagi logam X?
C
Zink
B
Tin
Stanum
Lead Plumbum
D Copper
Persamaan di bawah menunjukkan penguraian nitrat apabila dipanaskan.
2Mg(NO3)2 2MgO + 4NO2 + O2
Metal X
A Zinc
11 The equation shows a decomposition of magnesium nitrate when heated.
Kuprum
10 The following equation shows the decomposition reaction of lead(II) nitrate when heated at room temperature and pressure. Persamaan tindak balas di bawah menunjukkan penguraian plumbum(II) nitrat apabila dipanaskan pada suhu dan tekanan bilik.
Berapakah bilangan molekul oksigen apabila 7.4 g magnesium nitrat terurai apabila dipanaskan? [Jisim formula relatif Mg(NO3)2 = 148; Pemalar Avogadro = 6.02 × 1023 mol–1]
A B C D
12 The equation below shows the chemical equation of the combustion of ethanol in excess oxygen. Persamaan di bawah menunjukkan persamaan kimia pembakaran etanol dalam oksigen berlebihan.
2Pb(NO3)2 2PbO + 4NO2 + O2 Which of the following are true when 0.1 mol of lead(II) nitrate is decomposed? [Relative atomic mass: N = 14, O = 16, Pb = 207 and 1 mol gas occupies the volume of 24 dm3 at room temperature and pressure] Antara berikut, yang manakah adalah benar apabila 0.1 mol plumbum(II) nitrat terurai? [Jisim atom relatif: N = 14, O = 16, Pb = 207 dan 1 mol gas menempati isipadu 24 dm3 pada suhu dan tekanan bilik]
I
66.2 g of lead(II) oxide is formed 66.2 g plumbum(II) oksida terbentuk
II 22.3 g of lead(II) oxide is formed
22.3 g plumbum(II) oksida terbentuk
III 2.4 dm3 of oxygen gases is given off
2.4 dm3 gas oksigen dibebaskan
IV 4 800 cm3 of nitrogen dioxide given off
4 800 cm3 nitrogen dioksida dibebaskan
A I and III only I dan III sahaja
B
I and IV only
C
II and III only
I dan IV sahaja II dan III sahaja
D II and IV only
m
2C2H5OH + 6O2 4CO2 + 6H2O What is the volume of carbon dioxide gas released when 9.20 g ethanol burnt completely? [Relative atomic mass of H = 1, C = 12, O = 16, 1 mol of gas occupies 24 dm3 at room condition] Apakah isi padu gas karbon dioksida dibebaskan apabila 9.20 g etanol terbakar lengkap? [Jisim atom relatif: H = 1, C = 12, O = 16, 1 mol gas menempati 24 dm3 pada keadaan bilik]
A B C D
4.8 cm3 9.6 cm3 96.0 cm3 9 600 cm3
13 What is the percentage by mass of nitrogen content in urea, CO(NH2)2? [Relative atomic mass: C = 12, N = 14, H = 1 and O = 16] Apakah peratus kandungan nitrogen mengikut jisim dalam urea, CO(NH2)2? [Jisim atom relatif: C = 12, N = 14, H = 1 dan O = 16]
A B C D
23.3% 31.8% 46.7% 63.6%
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II dan IV sahaja
1.505 × 1022 3.010 × 1022 1.505 × 1023 3.010 × 1023
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Chemistry Form 4 • MODULE
3
PERIODIC TABLE JADUAL BERKALA
HISTORICAL DEVELOPMENT / SEJARAH PERKEMBANGAN – To identify the contribution of scientists in the arrangement of elements in the Periodic Table. Mengetahui sumbangan ahli sains untuk penyusunan unsur dalam Jadual Berkala. – To get ideas on the arrangement of elements in the Periodic Table based on their proton numbers. Mendapat idea penyusunan unsur dalam Jadual Berkala berdasarkan nombor proton.
ARRANGEMENT OF ELEMENT IN THE PERIODIC TABLE / PENYUSUNAN UNSUR DALAM JADUAL BERKALA • GROUP / KUMPULAN – To write the electron arrangement for atoms of elements with proton numbers 1 to 20. Menulis susunan elektron bagi atom unsur dengan proton 1 hingga 20. • PERIOD / KALA – To determine the group and period based on the electron arrangement of atoms or otherwise. Menentukan kumpulan dan kala berdasarkan susunan elektron atom dan sebaliknya.
PROPERTIES OF ELEMENTS IN THE PERIODIC TABLE / SIFAT-SIFAT UNSUR DALAM JADUAL BERKALA • GROUP 18 / KUMPULAN 18 – To explain the existence of noble gases as monoatom and their uses. Menerangkan kewujudan gas adi secara monoatom serta kegunaannya. • GROUP 1 / KUMPULAN 1 – To explain physical properties, similar chemical properties (with water, oxygen and chlorine) and the different reactivities. Menerangkan sifat fizik, sifat kimia yang sama (dengan air, oksigen dan dengan klorin) serta kereaktifan yang berbeza. • GROUP 17 / KUMPULAN 17 – To explain physical properties, similar chemical properties (with water, sodium hydroxide and iron) and the different reactivities. Menerangkan sifat fizik, sifat kimia yang sama (dengan air, natrium hidroksida dan ferum) serta kereaktifan yang berbeza. • PERIOD 3 / KALA 3 – To explain changes in atomic size, electronegativity, metallic properties as well as oxide properties across period 3 from left to right. Menerangkan perubahan saiz atom, keelektronegatifan, sifat kelogaman serta sifat oksida merentasi Kala 3 dari kiri ke kanan.
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• TRANSITION ELEMENTS / UNSUR PERALIHAN – To state metallic properties of transition metals and their special characteristics. Menyatakan sifat kelogaman unsur peralihan serta ciri-ciri istimewa unsur peralihan.
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MODULE • Chemistry Form 4
ADVANTAGES OF CLASSIFYING THE ELEMENTS IN THE PERIODIC TABLE KEBAIKAN PENGELASAN UNSUR DALAM JADUAL BERKALA
1
Elements are arranged systematically in the Periodic Table in an increasing order of proton number which enables: Unsur disusun secara sistematik dalam Jadual Berkala mengikut tertib pertambahan nombor proton yang membolehkan:
(a) Chemists to study, understand and remember the chemical and physical properties of all the elements and compounds in an orderly manner, Ahli kimia mempelajari, memahami dan mengingat sifat kimia dan sifat fizik semua unsur dan sebatian secara teratur.
(b) Properties of elements and their compounds to be predicted based on the position of elements in the Periodic Table, Sifat unsur dan sebatiannya diramal berdasarkan kedudukan unsur dalam Jadual Berkala.
(c) Relationship between elements from different groups to be known. Perhubungan unsur dari kumpulan yang berlainan diketahui.
CONTRIBUTION OF SCIENTIST TO THE HISTORICAL DEVELOPMENT OF THE PERIODIC TABLE SUMBANGAN AHLI SAINS DALAM SEJARAH PERKEMBANGAN JADUAL BERKALA
Scientists / Saintis Antoine Lavoisier
Discoveries / Penemuan – Substances were classified into 4 groups with similar chemical properties. Bahan dikelaskan kepada empat kumpulan dengan sifat kimia sama.
J.W Dobereiner
– Substances were arranged in 3 groups / Bahan disusun dalam tiga kumpulan. – Groups with similar chemical properties were called Triads. Kumpulan dengan sifat kimia sama dinamakan triad.
– Triad system was confined to some elements only / Sistem triad terhad kepada beberapa unsur sahaja. John Newlands
– Elements were arranged in ascending atomic mass / Unsur disusun mengikut pertambahan jisim atom. – Law of Octaves because similar chemical properties were repeated at every eighth element. Hukum Oktaf kerana sifat sama berulang pada setiap unsur kelapan.
– This system was inaccurate because there were some elements with wrong mass numbers. Sistem ini tidak tepat kerana ada unsur dengan nombor jisim salah.
Lothar Meyer
Mass of 1 mol (g) / Jisim 1 mol (g) Density (g cm–3) / Ketumpatan (g cm–3) – Plotted graph for the atomic volume against atomic mass / Memplotkan graf isi padu atom melawan jisim atom. – Found that elements with similar chemical properties were positioned at equivalent places along the curve. – The atomic volume / Isipadu atom =
Mendapati unsur dengan sifat kimia sama menduduki tempat setara dalam lengkungan.
Mendeleev
– Elements were arranged in ascending order of increasing atomic mass. Unsur disusun mengikut pertambahan jisim atom.
– Elements with similar chemical properties were in the same group. Unsur dengan sifat kimia sama berada dalam kumpulan sama.
– Empty spaces were allocated for elements yet to be discovered. Ruang kosong disediakan untuk unsur yang belum ditemui.
– Contributor to the formation of the modern Periodic Table. Penyumbang kepada pambentukan Jadual Berkala Moden.
Henry Moseley
– Classified concepts of proton number and elements in ascending order of increasing proton number. Mengelaskan unsur berdasarkan konsep nombor proton dan menyusun unsur-unsur mengikut turutan nombor proton menaik.
– Contributor to the formation of the modern Periodic Table.
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Chemistry Form 4 • MODULE
THE ARRANGEMENT OF ELEMENTS IN THE MODERN PERIODIC TABLE SUSUNAN UNSUR DALAM JADUAL BERKALA MODEN
1
Write the electron arrangement for each atom of element in the Periodic Table below. Tuliskan susunan elektron untuk setiap atom unsur dalam Jadual Berkala di bawah. Nucleon number / Nombor nukleon Proton number / Nombor proton
A Z
X
Symbol of an element / Simbol unsur
GROUP / KUMPULAN 1 1
P E R I O D / K A L A
2 3
1
3
Li
11
8 4
19
K
2.8.8.1
11
Be
2.1 Na
13
2 5
2.2 24 12
2.8.1 39
4
2
1
23
3
4
H*
1
7
2
18
LOGAM PERALIHAN
40 20
27 13
2.8.2
3
4
5
6
7
8
9
12
B
6
2.3
TRANSITION METALS
Mg
14 14
C
7
2.4 28
Al
16 16
N
8
2.5 31
Si
14
2.8.3
10 11 12
15
15
2.8.4
32 16
2.8.5
2
17 19
O
9
2.6
P
He
20
F
Ne
10
2.7 35
S
17
2.8.6
40
Cl
80 35
2.8.8.2
Elements in the Periodic Table are arranged horizontally in increasing order of
proton number
.
Unsur-unsur dalam Jadual Berkala disusun secara mendatar mengikut tertib pertambahan
nombor proton
.
Ar
18
2.8.7
Ca
2.8
2.8.8
Br
Two main components of the Periodic Table / Dua komponen utama Jadual Berkala: (a) Group / Kumpulan (b) Period / Kala GROUP / KUMPULAN
1
The vertical column of elements in the Periodic Table arranged according to the number of valance electron in the outermost shell of atoms is called groups. Lajur
menegak
petala terluar
2
dalam Jadual Berkala yang disusun mengikut bilangan
elektron valens
yang terdapat pada
bagi atom dipanggil kumpulan.
There are 18 vertical columns, called Group 1, Group 2, and Group 3 until Group 18. Terdapat 18 lajur disusun secara menegak disebut Kumpulan 1, Kumpulan 2, Kumpulan 3 hingga Kumpulan18. Number of valence electrons
1
2
3
4
5
6
7
Group
1
2
13
14
15
16
17
Bilangan elektron valens Kumpulan
8 (except Helium) 8 (kecuali Helium)
18
For atoms of elements with 3 to 8 valence electrons, the group number is: 10 + number of valence electrons.
Bagi atom unsur dengan 3 hingga 8 elektron valens, nombor kumpulan ialah: 10 + bilangan elektron valens.
Specific name of groups / Nama-nama khas kumpulan: (a) Group 1: Alkali metals # / Kumpulan 1: Logam alkali # (b) Group 2: Alkali-earth metals / Kumpulan 2: Logam alkali bumi (c) Group 3 to 12: Transition elements # / Kumpulan 3 to 12: Unsur peralihan # (d) Group 17: Halogens # / Kumpulan 17: Halogen # n io
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(e) Group 18: Noble gases # / Kumpulan 18: Gas adi # #The important groups that will be studied with respect to chemical and physical properties. # Kumpulan penting yang akan dipelajari dari segi sifat fizik dan sifat kimia.
4
Types of substances according to the groups / Jenis bahan mengikut kumpulan: (a) Elements of group 1, 2 and 13 – atoms of each element have 1, 2 and 3 valence electrons respectively are metals. Unsur Kumpulan 1, 2 dan 13 – atom setiap unsur mempunyai 1, 2 dan 3 elektron valens adalah logam.
(b) The elements of group 3 to 12 – transition elements are metals. Unsur Kumpulan 3 hingga 12 – unsur peralihan yang merupakan logam.
(c) The elements of Group 14, 15, 16, 17 and 18 – atoms of each element have 4, 5, 6, 7 and 8 valence electrons respectively are non-metals. Unsur Kumpulan 14, 15, 16, 17 dan 18 – atom setiap unsur mempunyai 4, 5, 6, 7 dan 8 elektron valens adalah bukan logam.
PERIOD / KALA The horizontal row of elements in the Periodic Table, consists of the same number of electrons in an atom called period.
1
Baris unsur secara atom
dalam
2
mendatar
dalam Jadual Berkala, mempunyai bilangan
petala
berisi
shell
occupied with
elektron
yang sama di
disebut sebagai kala.
There are seven horizontal rows of elements known as Period 1, 2, ....., 7 [Refer to the Periodic Table] Terdapat tujuh baris unsur secara mendatar disebut Kala 1, 2, ....., 7 [Rujuk Jadual Berkala]
(a) Period 1 has 2 elements / Kala 1 mengandungi 2 unsur (b) Period 2 and 3 have 8 elements # / Kala 2 dan 3 mengandungi 8 unsur # (c) Period 4 and 5 have 18 elements / Kala 4 dan 5 mengandungi 18 unsur (d) Period 6 has 32 elements / Kala 6 mengandungi 32 unsur (e) Period 7 has 23 elements / Kala 7 mengandungi 23 unsur
Short periods, # Period 3 will be studied in detail with respect to physical and chemical properties / Kala pendek, # Kala 3 akan dipelajari dengan terperinci dari segi sifat fizik dan sifat kimia
Long periods / Kala panjang
EXERCISE / LATIHAN 1
Complete the table below / Lengkapkan jadual berikut. Element Unsur
Proton number Nombor proton
Electron arrangement Susunan elektron
Number of valence electrons
Kumpulan
Group
Number of shell
Period
Bilangan petala
Kala
m
H
1
1
1
1
1
1
He
2
2
2
18
1
1
Li
3
2.1
1
1
2
2
Be
4
2.2
2
2
2
2
B
5
2.3
3
13
2
2
C
6
2.4
4
14
2
2
N
7
2.5
5
15
2
2
O
8
2.6
6
16
2
2
F
9
2.7
7
17
2
2
Ne
10
2.8
8
18
2
2
Na
11
2.8.1
1
1
3
3
Mg
12
2.8.2
2
2
3
3
Al
13
2.8.3
3
13
3
3
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Chemistry Form 4 • MODULE
2
The diagram below shows the chemical symbols which represent elements X, Y and Z. Rajah di bawah menunjukkan simbol kimia yang mewakili unsur X, Y dan Z. 23 11
X
12 6
Y
39 19
Z
(a) Explain how to determine the position of element X in the Periodic Table. Terangkan bagaimana menentukan kedudukan unsur X dalam Jadual Berkala.
The proton number of element X is 11 and the number of proton in electrons in atom X is 11 . The electron arrangement of atom X is 1
because three shells
atom 2.8.1
atom
X has one valence electron . Element X is in period occupied with electrons .
X is
11
. The number of
. Element X is located in Group 3 because atom X has
atom X adalah 11 . Bilangan elektron dalam atom Nombor proton unsur X adalah 11 dan bilangan proton dalam 11 . Susunan elektron bagi atom 2.8.1 . Unsur X terletak dalam kumpulan 1 X adalah kerana X adalah atom satu elektron valens 3 atom tiga X mempunyai . Unsur X berada dalam kala kerana X mempunyai berisi elektron dengan . petala
(b) (i)
State the position of element Y in the Periodic Table. / Nyatakan kedudukan unsur Y dalam Jadual Berkala. Element Y is located in Group 14 and Period 2.
(ii)
Explain how to determine the position of element Y in the Periodic Table. Terangkan bagaimana anda menentukan kedudukan unsur Y dalam Jadual Berkala.
– The proton number of element Y is 6 and the number of proton in atom Y is 6. – The electron arrangement of atom Y is 2.4. – Element Y is located in Group 14 because atom Y has 4 valance electron. – Element Y is in Period 2 because atom Y has 2 shells occupied/filled with electrons. (c) Which of the above elements show the same chemical properties? Explain your answer. Antara unsur di atas, yang manakah mempunyai sifat kimia yang sama? Terangkan jawapan anda.
– Element X and element Z. – Electron arrangement of atom X is 2.8.1 and electron arrangement of atom Z is 2.8.8.1. Atoms X and Z have the same number of valence electron.
GROUP 18 (NOBLE GASES) / KUMPULAN 18 (GAS ADI) 1
Consist of Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn). Terdiri dari Helium (He), Neon (Ne), Argon (Ar), Kripton (Kr), Xenon (Xe) dan Radon (Rn). Elements / Unsur
Electron arrangement / Susunan elektron
Helium / Helium Neon / Neon Argon / Argon Krypton / Kripton
2
2 2.8 2.8.8 2.8.18.8
Noble gases are chemically inert because the outermost shell of the atom has achieved duplet electron arrangement for helium and octet electron arrangement for others. Unsur Kumpulan 18 adalah lengai secara kimia kerana petala terluar atomnya telah mencapai susunan elektron duplet untuk helium dan susunan elektron oktet untuk yang lain.
3
Noble gases do not react with other elements (the atom does not lose, gain or share electrons). Unsur Kumpulan ini tidak bergabung dengan unsur lain (atomnya tidak akan menderma, menerima, atau berkongsi elektron).
4
These gases exist as single uncombined atoms and are said to be monatomic gases.
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Gas ini wujud sebagai atom tunggal iaitu sebagai gas monoatom.
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MODULE • Chemistry Form 4
5
Going down Group 18 / Menuruni Kumpulan 18: (a) The atomic size is increasing because the number of Saiz atom bertambah kerana bilangan
petala
shells
increases.
bertambah.
(b) The melting point and boiling points are very low because atoms of noble gases atoms are attracted by weak Van der Waals forces, less energy is required to overcome these forces. However, the melting and boiling points increase going down the group because atomic size increases, causing the Van der Waal forces to more increase and energy is required to overcome these forces. Takat lebur dan takat didih sangat rendah kerana atom-atom gas adi ditarik oleh daya Van der Waals yang lemah , sedikit tenaga diperlukan untuk mengatasi daya tersebut. Walau bagaimanapun, takat lebur dan takat didih bertambah menuruni kumpulan kerana pertambahan saiz atom menyebabkan daya tarikan Van der Waals semakin bertambah, semakin banyak tenaga diperlukan untuk mengatasinya.
(c) The density is low and increases gradually because the mass increases greatly compared to the volume going down the group. Ketumpatan rendah dan semakin meningkat kerana jisim bertambah dengan banyak berbanding dengan isi padu menuruni kumpulan.
6
All noble gases are insoluble in water and cannot conduct electricity in all conditions. Semua gas adi tidak larut dalam air dan tidak dapat mengkonduksikan elektrik dalam semua keadaan.
7
Complete the uses of noble gases in the table below / Lengkapkan jadual kegunaan gas adi. Noble gases / Gas adi
Uses / Kegunaan
Helium / Helium
To fill weather balloons and airship.
Neon / Neon
To fill neon light (for advertisement board).
Argon / Argon
To fill electrical bulb.
Krypton / Kripton
To fill photographic flash lamp.
Radon / Radon
To treat cancer.
GROUP 1 (ALKALI METALS) / KUMPULAN 1 (LOGAM ALKALI) 1
Consist of Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). Terdiri dari Litium (Li), Natrium (Na), Kalium (K), Rubidium (Rb), Sesium (Cs) dan Fransium (Fr). Elements
Symbol
Proton number
Electron arrangement
Number of shells
Lithium / Litium
Li
3
2.1
2
Sodium / Natrium
Na
11
2.8.1
3
Potassium / Kalium
K
19
2.8.8.1
4
Unsur
2
Simbol
Nombor proton
Susunan elektron
Bilangan petala
Physical properties / Sifat fizik: (a) Grey solid with shiny surface / Pepejal kelabu dengan permukaan berkilat. (b) Softer and the density is lower compared to other metals. Lebih lembut dan ketumpatan yang lebih rendah berbanding dengan logam lain.
(c) Lower melting and boiling points compared to other metals. Takat lebur dan takat didih lebih rendah berbanding dengan logam lain.
3
Changes in physical properties going down the group / Perubahan sifat fizik menuruni kumpulan: (a) Atomic size increases because the number of shells increases / Saiz atom bertambah kerana bilangan petala bertambah. (b) Density increases because mass increases faster than the increase in radius. Ketumpatan bertambah kerana pertambahan jisim lebih cepat dari pertambahan jejari
(c) Melting and boiling points decrease because when the atomic size increases, the metal bonds get weaker. Takat didih dan takat lebur berkurang kerana apabila saiz atom bertambah, ikatan logam semakin lemah.
4
Chemical properties of Group 1 elements / Sifat kimia unsur Kumpulan 1: atoms 1 (a) All of elements in Group 1 have valence electron and achieve a stable duplet/octet electron arrangement by releasing
m
Semua melepaskan
Publica
electron to form
+1
charged ions:
1
unsur mempunyai elektron valens dan mencapai susunan elektron oktet/duplet yang stabil dengan satu +1 elektron valens membentuk ion bercas .
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Chemistry Form 4 • MODULE
Example / Contoh: (i) Atom releases one electron to achieve stable duplet electron arrangement: Atom litium melepaskan satu elektron untuk mencapai susunan elektron duplet yang stabil:
Li
+e
Electron arrangement / Susunan elektron : 2.1 Number of protons = 3, total charge: +3
Electron arrangement / Susunan elektron : 2 Number of protons = 3, total charge: +3
Bilangan proton = 3,
Bilangan proton = 3,
jumlah cas: +3
jumlah cas: +3
Number of electrons = 3, total charge: –3
Number of electrons = 2, total charge: –2
Bilangan elektron = 3,
Bilangan elektron = 2,
jumlah cas: –3
neutral
Lithium atom is
neutral
Atom litium adalah
(ii)
Li+
Positively
.
charges lithium ion, Li+ is formed. positif
Ion litium bercas
.
jumlah cas: –2 , Li+ terbentuk.
Sodium atom releases one electron to achieve stable octet electron arrangement: Atom natrium melepaskan satu elektron untuk mencapai susunan elektron oktet yang stabil:
Na
Na+
Electron arrangement / Susunan elektron : 2.8.1 Number of protons = 11, total charge: +11 Bilangan proton = 11,
Electron arrangement / Susunan elektron : 2.8 Number of protons = 11, total charge: +11
jumlah cas: +11
Bilangan proton = 11,
Number of electrons = 11, total charge: –11 Bilangan elektron = 11,
Atom natrium adalah
neutral
jumlah cas:
+11
–10
Number of electrons = 10, total charge:
jumlah cas: –11
neutral
Sodium atom is
+e
Bilangan elektron = 10,
.
Positively
.
jumlah cas:
–10
charges sodium ion, Na+ is formed.
Ion natrium bercas
positif
, Na+ terbentuk.
atoms (b) All elements in Group 1 have similar chemical properties because all in Group 1 have one valence electron releasing electron and achieve the stable duplet/octet arrangement by its valence electron to form a
positively
charged ions.
atom unsur Kumpulan 1 mempunyai bilangan Semua unsur Kumpulan 1 mempunyai sifat kimia yang sama kerana semua elektron yang stabil dengan melepaskan satu elektron valensnya elektron valens yang sama iaitu satu dan mencapai susunan untuk membentuk ion bercas
5
positif
.
The reactivity of alkali metals increases going down the Group 1: Kereaktifan unsur logam alkali bertambah menuruni Kumpulan 1:
– Atoms of Group 1 metals achieve a stable duplet/octet electron arrangement one by releasing valence electron to form +1 charged ion.
Menuruni Kumpulan 1, bilangan
petala
elektron valens pada petala terluar semakin
bertambah, saiz atom bertambah dan jauh dari nukleus.
– The strength of attraction from the proton in the nucleus to the valence weaker . elecron gets Kekuatan tarikan nukleus kepada elektron valens semakin
– The valence electron is loosely held and it is be released.
Li
Na
K
.
easier
for the electron to
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Elektron valens ditarik dengan lemah dan ia makin
lemah
down Group 1
increases, the atomic size further increases and the valence electron in the outer most shell gets away from the nucleus.
increases
shells
menurun Kumpulan 1
– Going down Group 1, the number of
Reactivity
Kereaktifan logam Kumpulan 1 bergantung pada kesenangan atom melepaskan elektron, semakin senang elektron dilepaskan, kereaktifan logam semakin bertambah .
bertambah
– The reactivity of Group 1 metals depends on the tendency for atoms to lose electrons; the easier it loses an electron, the reactivity of the metal increases .
Kereaktifan
Atom logam Kumpulan 1 mencapai susunan elektron gas adi yang stabil dengan satu melepaskan elektron valens membentuk ion bercas +1.
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MODULE • Chemistry Form 4
6
Chemical reactions of Group 1 elements / Tindak balas kimia unsur Kumpulan 1: (a) Metal Group 1 reacts with water to produce alkali and hydrogen gas. Logam Kumpulan 1 bertindak balas dengan air menghasilkan alkali dan gas hidrogen.
2X + 2H2O
2X + 2H2O
2XOH + H2, X is the metal of Group 1
2XOH + H2 , X adalah logam Kumpulan 1 Lithium / Litium Water / Air
Procedure / Kaedah: (i) Cut a small piece of lithium using a knife and forceps. Potong sepotong litium menggunakan pisau dan forsep.
(ii)
Dry the oil on the surface of the lithium with filter paper. Keringkan minyak pada permukaan litium menggunakan kertas turas.
(iii) Place the lithium slowly onto the water surface in a water trough. Letakkan litium dengan perlahan di atas permukaan air di dalam bekas.
(iv) When the reactions stop, test the solution produced with red litmus paper. Apabila tindak balas berhenti, uji larutan yang terhasil dengan kertas litmus merah.
(v) Record the observation / Catatkan semua pemerhatian. (vi) Repeat steps (i) – (v) using sodium and potassium to replace lithium one by one. Ulang langkah (i) – (v) dengan menggunakan natrium dan kalium menggantikan litium satu demi satu.
Observation / Pemerhatian: Element
Observation
Li
Lithium moves slowly on the water red surface and produces flame. The colourless solution formed turns red litmus to blue .
Unsur
Inference
Pemerhatian
Inferens
perlahan
quickly
Sodium moves
surface and produces
on the water yellow flame. The
colourless solution formed turns red litmus to blue . Natrium bergerak cepat dengan nyalaan kuning di atas permukaan air. Larutan tidak berwarna menukarkan kertas litmus merah kepada biru .
K
Potassium moves
very quickly
on the
yellow
flame. water surface and produce The colourless solution formed turns red litmus blue . to sangat cepat
m
lithium hydroxide: Litium adalah logam yang paling kurang reaktif bertindak balas dengan air membentuk larutan beralkali , litium hidroksida.
Balanced equation / Persamaan kimia seimbang: 2Li + 2H2O 2LiOH + H2 Sodium is reactive metal reacts with water to produce alkaline solution, sodium hydroxide. reaktif bertindak Natrium adalah logam yang balas dengan air membentuk larutan beralkali , natrium hidroksida.
Balanced equation / Persamaan kimia seimbang: 2Na + 2H2O 2NaOH + H2 the most reactive
metal alkaline reacts with water to produce solution, potassium hydroxide. Potassium is
Kalium adalah logam yang paling reaktif bertindak balas dengan air membentuk larutan beralkali , kalium hidroksida.
Balanced equation / Persamaan kimia seimbang: 2K + 2H2O 2KOH + H2
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Lithium is the least reactive metal reacts with water to produce alkaline solution,
Reactivity increases down Group 1
Na
Kereaktifan
Kereaktifan bertambah menuruni Kumpulan 1
dengan nyalaan Litium bergerak merah di atas permukaan air. Larutan tidak berwarna menukarkan kertas litmus merah kepada biru .
Reactivity
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Chemistry Form 4 • MODULE
(b) Metal Group 1 reacts with oxygen or air to form metal oxide. The metal oxide dissolves in water to produce alkaline solution. Logam Kumpulan 1 bertindak balas dengan oksigen membentuk oksida logam. Oksida logam larut dalam air menghasilkan larutan berakali.
X2O + H2O X2O + H2O
4X + O2 2X2O 2XOH, X is a metal element of Group 1 (Li, Na and K) 2XOH, X adalah logam unsur Kumpulan 1 (Li, Na dan K) Combustion spoon / Sudu pembakaran Gas jar / Balang gas Chlorine gas / Gas klorin Burning lithium / Litium menyala
Procedure / Kaedah: (i) Cut a small piece of lithium using a knife and forceps / Potong secebis kecil litium menggunakan pisau dan forsep. (ii) Dry the oil on the surface of the lithium with filter paper. Keringkan minyak pada permukaan litium dengan kertas turas.
(iii) Place the lithium in a combustion spoon and heat lithium until it start to burn. Letakkan litium pada sudu pembakaraan dan panaskan litium dengan kuat hingga ia menyala.
(iv) Put the burning lithium into a gas jar of oxygen / Letakkan litium yang menyala dalam balang gas berisi oksigen. (v) When the reaction stop, add water to dissolve the compound formed. Apabila tindak balas berhenti, tambahkan air untuk melarutkan sebatian yang terbentuk.
(vi) Add a few drops of universal to the solution formed. Tambahkan beberapa titis penunjuk universal kepada larutan yang terbentuk.
(vii) Record the observation / Catatkan pemerhatian. (viii) Repeat steps (i) – (vii) using sodium and potassium to replace lithium one by one. Ulang langkah (i) – (vii) menggunakan natrium dan kalium untuk menggantikan litium satu demi satu.
Observation / Pemerhatian: Element
Observation
Unsur
Li
Inference
Pemerhatian
Litium adalah paling kurang reaktif terhadap oksigen.
form
colourless
– Lithium reacts with oxygen to produce lithium oxide .
soluble in water to solution.
Litium bertindak balas dengan oksigen membentuk litium oksida .
Pepejal putih larut dalam air membentuk tidak berwarna . larutan
– The solution turns green indicator to purple .
Balanced equation / Persamaan kimia seimbang: 4Li + O2 2Li2O
universal
Larutan itu menukarkan warna penunjuk hijau kepada ungu universal dari
.
– Lithium reacts with water to form alkaline solution, lithium hydroxide. Litium oksida bertindak balas dengan air membentuk larutan beralkali, litium hidroksida
Reactivity increases down Group 1
– Lithium is the least reactive metal towards oxygen.
Litium terbakar perlahan dengan nyalaan merah menghasilkan pepejal putih .
white solid
Kereaktifan
Kereaktifan bertambah menuruni Kumpulan 1
– Lithium burns slowly with a red flame to produce white solid .
– The
Reactivity
Inferen
.
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Balanced equation / Persamaan kimia seimbang: Li2O + H2O 2LiOH
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MODULE • Chemistry Form 4
Na
– Sodium burns brightly with a yellow flame to produce white solid . terang Natrium terbakar kuning menghasilkan
– The form
white solid
dengan nyalaan pepejal putih .
soluble in water to
colourless
solution.
Pepejal putih larut dalam air membentuk tidak berwarna . larutan
– The solution turns green indicator to purple .
universal
Larutan itu menukarkan warna penunjuk universal dari hijau kepada ungu
.
– Sodium is
reactive
Natrium adalah logam
metal towards oxygen. reaktif
terhadap oksigen.
– Sodium reacts with oxygen to produce sodium oxide . Natrium bertindak balas dengan oksigen membentuk natrium oksida .
Balanced equation / Persamaan kimia seimbang: 4Na + O2 2Na2O – Sodium reacts with water to form alkaline solution, sodium hydroxide. Natrium bertindak balas dengan air membentuk larutan beralkali , natrium hidroksida.
Balanced equation / Persamaan kimia seimbang: Na2O + H2O 2NaOH K
– Potassium burns very brightly with a purple flame to produce
– Potassium is the most reactive towards oxygen.
white solid . Kalium terbakar sangat terang dengan nyalaan ungu menghasilkan pepejal putih .
– The form
white solid
soluble in water to
colourless
solution.
Pepejal putih larut dalam air membentuk tidak berwarna . larutan
– The solution turns green indicator to purple .
universal
Larutan itu menukarkan warna penunjuk universal dari hijau kepada ungu
.
Kalium adalah logam oksigen.
paling reaktif
metal terhadap
– Potassium reacts with oxygen to produce potassium oxide . Kalium bertindak balas dengan oksigen membentuk kalium oksida .
Balanced equation / Persamaan kimia seimbang: 4K + O2 2K2O – Potassium reacts with water to form alkaline solution, potassium hydroxide. Kalium oksida bertindak balas dengan air membentuk larutan beralkali , kalium hidroksida.
Balanced equation / Persamaan kimia seimbang: K2O + H2O 2KOH
(c) Metal Group 1 reacts with with chlorine to produce metal chloride. Logam Kumpulan 1 bertindak balas dengan klorin menghasilkan logam klorida.
2X + Cl2
2X + Cl2 + 2H2O
X is a metal element of Group 1 (Li, Na and K) 2XCl , X adalah logam unsur Kumpulan 1 (Li, Na dan K)
Combustion spoon / Sudu pembakaran Gas jar / Balang gas Chlorine gas / Gas klorin Burning of metal Group 1
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Chemistry Form 4 • MODULE
Observation / Pemerhatian: Element
Observation
Unsur
Li
Inference
Pemerhatian
slowly
Lithium burns flame to produce
red
with a
white
Reactivity
Inferen
solid.
Litium terbakar perlahan dengan nyalaan merah putih menghasilkan pepejal
least reactive
– Lithium is chlorine. .
Litium adalah klorin.
Kereaktifan
metal towards
paling kurang reaktif
terhadap
– Lithium reacts with chlorin to produce lithium chloride . Litium bertindak balas litium klorida .
dengan klorin membentuk
Sodium burns brightly with a yellow flame to produce white solid. terang
– Sodium is
reactive
metal towards chlorine. reaktif
Natrium adalah logam
terhadap klorin.
reacts
with chlorine to produce – Sodium sodium chloride .
dengan nyalaan Natrium terbakar kuning menghasilkan pepejal putih .
Natrium bertindak balas dengan klorin membentuk natrium klorida .
Balanced equation / Persamaan kimia seimbang: 2Na + Cl2 2NaCl K
very brightly with Potassium burns a purple flame to produce white
– Potassium is the most reactive metal towards chlorine.
dengan nyalaan Kalium terbakar ungu menghasilkan pepejal putih .
paling reaktif
Kalium adalah logam klorin.
solid. sangat terang
Reactivity increases down Group 1
Na
Kereaktifan bertambah menuruni Kumpulan 1
Balanced equation / Persamaan kimia seimbang: 2Li + Cl2 2LiCl
terhadap
– Potassium reacts with chlorine to produce sodium chloride . Kalium
bertindak balas
kalium klorida
dengan klorin membentuk
.
Balanced equation / Persamaan kimia seimbang: 2K + Cl2 2KCl
GROUP 17 (HALOGENS) / KUMPULAN 17 (HALOGEN) 1
Consist of Fluorine (F2), Chlorine (Cl2), Bromine (Br2), Iodine (I2) and Astatine (At2).
Terdiri dari Fluorin (F2 ), Klorin (Cl2 ), Bromin (Br2 ), Iodin (I2 ) dan Astatin (At2 ). Elements
Symbol
Proton number
Fluorine / Fluorin
F2
Chlorine / Klorin
Cl2
Bromine / Bromin
Unsur
Iodine / Iodin
2
Electron arrangement
Number of shells
19
2.7
2
17
2.8.7
3
Br2
35
2.8.18.7
4
I2
53
2.8.18.18.7
5
Simbol
Nombor proton
Susunan elektron
Bilangan petala
Physical properties: Halogens cannot conduct heat and electricity in all state.
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MODULE • Chemistry Form 4
3
Changes in physical properties going down the group / Perubahan sifat fizik menuruni kumpulan: (a) The melting and boiling points are low because the molecules are attracted by weak Van der Waals forces, and small amount of energy is required to overcome these forces. However the melting and boiling points increase going down the group. Takat didih dan takat lebur adalah rendah kerana molekul ditarik oleh tarikan Van der Waals yang lemah, sedikit tenaga diperlukan untuk mengatasi daya itu. Walau bagaimanapun, takat lebur dan takat didih meningkat menuruni kumpulan. Explanation / Penerangan:
–
The atomic size increases molecules get larger. bertambah
Saiz atom
–
shell
going down the Group 17 because of increasing in number of
menuruni kumpulan kerana dengan pertambahan bilangan
petala
, the size
, saiz molekul semakin besar.
The inter molecular forces of attraction (Van der Waals forces) between molecules become stronger. Daya tarikan antara molekul (daya Van der Waals) antara molekul semakin kuat.
–
More heat is needed to overcome the stronger forces between molecules during melting or boiling. Lebih banyak tenaga diperlukan untuk mengatasi daya antara molekul yang lebih kuat semasa peleburan atau pendidihan.
(b) Physical properties change from gas (fluorine and chlorine) to liquid (bromine) and to solid (iodine) at room temperature due to increase in the strength of inter molecular forces from fluorine to iodine. Keadaan fizik berubah dari gas (flourin dan klorin) kepada cecair (bromin) dan kepada pepejal (iodin) pada suhu bilik kerana pertambahan kekuatan tarikan antara molekul dari flourin kepada iodin.
(c) The density is low and increases going down the group. Ketumpatan adalah rendah dan semakin meningkat apabila menuruni kumpulan.
darker (d) The colour of the elements becomes going down the group: fluorine (light yellow), chlorine (greenish yellow), bromine (brown) and iodine (purplish black). Warna unsur semakin iodin (ungu kehitaman).
4
gelap
menuruni kumpulan iaitu flourin (kuning muda), klorin (kuning kehijauan), bromin (perang) dan
Chemical properties of Group 17 elements / Sifat kimia unsur Kumpulan 17: atoms seven (a) All of elements in Group 17 have valence electrons and achieve a stable octet electron one negatively arrangement by accepting electron to form charged ions. atom
Semua menerima
satu
unsur Kumpulan 17 mempunyai elektron membentuk ion bercas
Example / Contoh: (i) Fluorine atom Atom
elektron valens, mencapai susunan elektron oktet yang stabil dengan negatif .
receives one electron to achieve stable duplet electron arrangement:
flourin menerima satu elektron untuk mencapai susunan elektron oktet yang stabil:
F
+e
F–
Electron arrangement / Susunan elektron : 2.7 Number of protons = 9, total charge: +9
Electron arrangement / Susunan elektron : 2.8 Number of protons = 9, total charge: +9
Bilangan proton = 9,
jumlah cas: +9
Bilangan proton = 9,
Number of electrons = 9,
total charge: –9
Number of electrons = 10, total charge: –10
Bilangan elektron = 9,
jumlah cas: –9
Bilangan elektron = 10,
neutral
Fluorine atom is Atom flourin adalah
(ii)
tujuh
Negatively
.
neutral
.
jumlah cas: +9 jumlah cas: –10
charged fluoride ion, F– is formed.
Ion flourida, F– bercas
negatif
terbentuk.
Chlorine atom receives one electron to achieve stable octet electron arrangement: Atom klorin menerima satu elektron untuk mencapai susunan elektron oktet yang stabil:
Cl
+e
Cl–
Electron arrangement / Susunan elektron : 2.8.7 Number of protons = 17, total charge: +17
Electron arrangement / Susunan elektron : 2.8.8 Number of protons = 17, total charge: +17
Bilangan proton = 17,
Bilangan proton = 17,
jumlah cas: +17
jumlah cas: +17
Number of electrons = 17, total charge: –17
Number of electrons = 18, total charge: –18
Bilangan elektron = 17,
Bilangan elektron = 18,
Chlorine atom is Atom klorin adalah
jumlah cas: –17
neutral neutral
. .
Negatively
jumlah cas: –18
charged chloride ion, Cl– is formed.
Ion klorida, Cl– bercas
negatif
terbentuk.
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(b) All elements in Group 17 have similar chemical properties because atoms in Group 17 have seven valence electron and achieve the stable octet electron arrangement by receiving one electron to form a negatively charged ion.
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Chemistry Form 4 • MODULE
atom tujuh unsur Kumpulan 17 mempunyai Semua unsur Kumpulan 17 mempunyai sifat kimia yang sama kerana menerima elektron valens sama dalam atom, mencapai susunan elektron oktet yang stabil dengan satu elektron membentuk ion negatif . bercas
5
Reactivity of halogens decreases going down the group / Kereaktifan halogen berkurang menuruni kumpulan: – All the atoms of Group 17 have seven valence electrons and achieve a stable octet electron arrangement by accepting one electron to form negatively charged ion.
– Going down Group 17, the number of Apabila menuruni Kumpulan 17, bilangan
petala
atom menerima elektron.
increases, atomic bertambah,
saiz
size
increases.
atom bertambah.
jauh
dari nukleus.
– The strength of attraction from the proton in the nucleus to attract one electron into the outermost occupied shell becomes weaker . Kekuatan tarikan daripada proton dalam nukleus untuk menarik satu elektron ke dalam petala luar semakin lemah .
– The strength of a halogen atom to attract electron astatine (electronegativity decreases). Kekuatan atom halogen untuk menarik elektron (keelektronegatifan berkurang).
6
decreases
berkurang
Cl
down Group 17
Petala luar semakin
menurun Kumpulan 17
– Outer shell becomes further from the nucleus.
F
decreases
shells
berkurang
kecenderungan
Kereaktifan unsur Kumpulan 17 bergantung pada
of the atom to receive
Reactivity
tendency
– The reactivity of a halogen atom depends on the electron.
Kereaktifan
Semua atom unsur Kumpulan 17 mempunyai tujuh elektron valens dan mencapai susunan elektron oktet yang stabil dengan menerima satu elektron membentuk ion bercas negatif .
Br
from fluorine to
dari fluorin ke astatin
Elements in group 17 exist as diatomic molecules. Two atoms of element sharing one pair of valence electrons to achieve stable octet electron arrangement. Unsur Kumpulan 17 wujud sebagai molekul dwiatom. Dua atom unsur berkongsi sepasang elektron valens untuk mencapai susunan elektron oktet yang stabil.
Example: Two fluorine atoms share one pair of electron to form one fluorine molecule: Contoh: Dua atom fluorin berkongsi sepasang elektron untuk membentuk molekul fluorin:
F
Share / Kongsi kongsi kongsi
Fluorine atom / Atom fluorin
F
F
F
Fluorine Molekul moleculeflorin / Molekul fluorin
Fluorine atom / Atom fluorin
Chlorine, bromine and iodine exists as diatomic molecules. (Cl2, Br2 and I2)
Klorin, bromin dan iodin wujud sebagai molekul dwiatom (Cl2 , Br2 dan I2 )
7
Chemical properties reactions of Group 17 elements / Tindak balas kimia unsur Kumpulan 17: (a) Halogen reacts with water with different reactivity / Halogen bertindak balas dengan air dengan kereaktifan berbeza: X2 + H2O
HX + HOX, X is halogen. (Cl2, Br2 and I2) / X2 + H2O
Chlorine gas / Gas Klorin
HX + HOX, X adalah halogen. (Cl2 , Br2 dan I2 )
Bromine water / Air Bromin
Chlorine
Iodine crystals / Hablur Iodin
Bromine
Gas klorin
Bromin
Water
water
Water air Air
Procedure / Kaedah: – Chlorine gas is passed through water in a test tube. Gas klorin dilalukan melalui air dalam tabung uji.
– The solution produced tested with blue litmus paper. Larutan yang terhasil diuji dengan kertas litmus biru.
Water / Air Procedure / Kaedah: – A few drops of bromine water are added to water in a test tube. Beberapa titis air bromin ditambah kepada air dalam tabung uji.
– The test tube is shaken. Tabung uji digoncang.
– The solution produced tested with blue litmus paper.
Iodine cystals Hablur iodin
Procedure / Kaedah: – Some iodine crystals are added to water in a test tube. Sedikit hablur iodin ditambah kepada air dalam tabung uji.
– The test tube is shaken. Tabung uji digoncang.
– The solution produced tested with blue litmus paper. Larutan yang terhasil diuji dengan kertas litmus biru. n io
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Larutan yang terhasil diuji dengan kertas litmus biru.
Air
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MODULE • Chemistry Form 4
Observation / Pemerhatian: – Chlorine dissolves rapidly in water to form light yellow solution: Klorin larut dengan cepat dalam air menghasilkan larutan berwarna kuning muda:
Cl2 + H2O
Observation / Pemerhatian: – Bromine dissolves slowly in water to form brown solution:
Bromin larut dengan perlahan dalam air menghasilkan larutan berwarna perang:
HCl + HOCl
– The solution changes red litmus paper to
Br2 + H2O
blue
qucikly decolourises it.
slowly decolourises it.
kepada merah dan dengan cepat.
kepada merah dan dengan perlahan.
Larutan menukarkan kertas litmus biru
blue and
Larutan menukarkan kertas litmus biru
melunturkannya
sedikit dalam Iodin larut dengan air menghasilkan larutan berwarna perang:
HBr + HOBr
– The solution changes red litmus paper to
and
Observation / Pemerhatian: – Iodine dissolves slightly in water to form brown solution:
melunturkannya
I2 + H2O
HI + HOI
– The solution changes red litmus paper to
blue
. The litmus paper is not decolourises . Larutan menukarkan kertas litmus biru kepada merah . Kertas litmus tidak dilunturkan .
Inference / Inferens: – Chlorine, bromine and iodine react water to form acidic solution. Klorin, bromin dan iodin bertindak balas dengan air membentuk larutan berasid.
– Solubility decreases from chlorine to iodine / Keterlarutan berkurang dari klorin kepada iodin.
(b) Halogens react with sodium hydroxide solution / Halogen bertindak balas dengan larutan natrium hidroksida: X2 + 2NaOH
X2 + 2NaOH
NaX + NaOX + H2O, X2 is halogen. (Cl2, Br2 and I2)
NaX + NaOX + H2O, X2 adalah halogen. (Cl2 , Br2 dan I2 )
Complete the following / Lengkapkan yang berikut: (i)
Cl2 + 2NaOH
(ii)
Br2 + 2NaOH
(iii) I2 + 2NaOH
NaCl + NaOCl + H2O
Reactivity decreases
NaBr + NaOBr + H2O
Kereaktifan berkurang
NaI + NaOI + H2O
(c) Halogens react with hot iron to form brown solid, iron(III) halide. Halogen bertindak balas dengan besi panas membentuk pepejal perang, ferum(III) halida. Iron wool / Wul besi Iodine Iodin
Chlorine or Bromine Klorin atau Bromin
Iron wool
Heat
Wul besi
Haba
NaOH to absorb chlorine/bromine NaOH untuk menyerap klorin/bromin
2Fe + 3X2 2Fe + 3X2
2FeX3, X2 represents any halogen. (Cl2, Br2 or I2)
2FeX3, X2 mewakili sebarang halogen. (Cl2 , Br2 atau I2 )
Halogen
Observation
Halogen
Chlorine Klorin
Bromin
Iron wool burns when cooled.
very brightly
Iodin
dan membentuk pepejal perang
dan membentuk pepejal
2Fe + 3Cl2
2FeCl3
2Fe + 3Br2
2FeBr3
with a dull glow and forms a
perlahan
dan membentuk pepejal perang
2Fe + 3I2
2FeI3
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and forms a brown solid
sangat terang
Iron wools glows slowly brown solid when cooled. Wul besi berbara dengan apabila sejuk.
m
terang
Persamaan kimia
Iron wool burns brightly and forms a brown solid when cooled. Wul besi berbara dengan perang apabila sejuk.
Iodine
Chemical equation
Pemerhatian
Wul besi terbakar dengan apabila sejuk.
Bromine
Heat / Haba
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Chemistry Form 4 • MODULE
similar
Experiment (a), (b) dan (c) show that all halogens have decreases going down the group:
chemical properties but their reactivity sama
Eksperimen (a), (b) dan (c) menunjukkan semua halogen menunjukkan sifat kimia yang berkurang apabila menuruni kumpulan. Reactivity
decreases
tetapi kereaktifannya
berkurang
/ Kereaktifan
F2, Cl2, Br2 and I2 / F2 , Cl2 , Br2 dan I2
PERIOD / KALA 1 2 3
Horizontal rows in the periodic table / Baris mendatar dalam Jadual Berkala. There are seven periods known as Period 1, 2, 3, 4, 5, 6, 7 / Terdapat 7 kala ditulis sebagai Kala 1, 2, 3, 4, 5, 6, 7. The number of period of an element represents the number of shells occupy with electrons in each atom of element. Nombor kala suatu unsur mewakili bilangan petala yang diisi oleh elektron di dalam setiap atom unsur. Elements
Proton number
Unsur
4
Nombor proton
Number of shells
Period
Susunan elektron
Bilangan petala
Kala
Li
3
2.1
2
2
Na
11
2.8.1
3
3
K
19
2.8.8.1
4
4
Period 3 elements (complete the following table): / Unsur Kala 3 (lengkapkan jadual berikut): Elements / Unsur
Na
Mg
Al
Si
P
S
Cl
Ar
11
12
13
14
15
16
17
18
2.8.1
2.8.2
2.8.3
2.8.4
2.8.5
2.8.6
2.8.7
2.8.8
3
3
3
3
3
3
3
3
+11
+12
+13
+14
+15
+16
+17
+18
0.191
0.160
0.130
0.118
0.110
0.102
0.099
0.095
Proton number Nombor proton
Electron arrangement Susunan elektron
Number of shells Bilangan petala
Positive charge in the nucleus Bilangan cas positif dalam nukleus
Radius (nm) Jejari (nm)
5
Electron arrangement
Physical changes across the Period 3 (from left to right) / Perubahan fizik merentasi Kala 3(dari kiri ke kanan): (a) Change in atomic radius across Period 3 / Perubahan jejari atom merentasi Kala 3: The atomic radius of the atoms decreases from sodium to chlorine berkurang dari natrium kepada klorin
Jejari atom
Na
Mg
Al
Si
S
P
Cl
16 p
Atom / Atom
Na
Mg
Al
Si
P
S
Cl
Number of proton / Bilangan proton
11 p
12 p
13 p
14 p
15 p
16 p
17 p
Positive charge / Cas positif
+11
+12
+13
+14
+15
+16
+17
Electron arrangement / Susunan elektron
2.8.1
2.8.2
2.8.3
2.8.4
2.8.5
2.8.6
2.8.7
–
All the atoms of elements have 3
shells
occupied with electrons
.
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Semua atom unsur mempunyai
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MODULE • Chemistry Form 4
–
The proton number
increases
by one unit from sodium to chlorine.
Nombor proton bertambah satu unit dari natrium kepada klorin.
– –
Increase in proton number causes the number of
positive
Pertambahan nombor proton menyebabkan bilangan cas
positif
increase
charge in the nucleus to
.
bertambah .
pada nukleus
increases .
The strength of attraction from the proton in the nucleus to the electrons in the shells bertambah . across period 3 / Jejari atom unsur berkurang
Daya tarikan proton dalam nukleus terhadap elektron dalam petala
– The size of atom decreases (b) Change in electronegativity / Perubahan keelektronegatifan: –
The atomic radius decreases sodium to chlorine. berkurang
Jejari atom klorin.
–
elektron
berkurang
Keelektonegatifan
bertambah
dari natrium kepada
dari natrium kepada klorin.
increases
Tendency of atoms to attract electron to the outermost shells The electronegativity
ke arah nukleusnya.
from sodium to chlorine.
bertambah
Kekuatan nukleus menarik elektron kepada petala paling luar
–
towards its nucleus.
due to the increasing nuclei attraction on the electrons in the shells from
kerana daya tarikan nukleus terhadap elektron dalam petala
decreases
The size of atom Saiz atom
–
electron
Electronegativity: The strength of an atom in a molecule to attract Kelektronegatifan: Kekuatan suatu atom dalam molekul menarik
–
merentasi Kala 3.
increases
bertambah
from sodium to chlorine.
dari natrium kepada klorin.
across Period 3 from sodium to chlorine.
merentasi Kala 3 dari natrium kepada klorin.
(c) Physical state / Keadaan fizik: (i) The physical state of elements in a period changes from solid to gas from left to right. Keadaan fizik unsur-unsur dalam suatu kala berubah dari pepejal kepada gas dari kiri ke kanan.
(ii)
Metals on the left are solid while non-metals on the right are usually gases. Logam di sebelah kiri adalah pepejal dan bukan logam di sebelah kanan kebanyakannya adalah gas.
(d) Changes in metallic properties and electrical conductivity / Perubahan sifat kelogaman dan kekonduksian elektrik: Na
Element / Unsur
Al
Si
P
S
Cl
Ar
Metallic properties
Semi metal
Non-metal
Sifat kelogaman
Logam
Separa logam
Bukan logam
Electrical conductivity
Good conductors of electric.
Weak conductor of electric but it increases with the presence of boron or phosphorous.
Cannot conduct electricity
Konduktor elektrik yang baik.
Konduktor elektrik yang lemah tetapi bertambah dengan kehadiran boron atau fosforus. Uses: semi-conductor / Kegunaan: semi konduktor
Kekonduksian elektrik
6
Mg
Metal
Tidak boleh mengkonduksi elektrik
Changes in properties of oxide of elements Period 3 / Sifat oksida unsur Kala 3: Na
Mg
Basic oxide / Oksida bes Basic oxide + Water Oksida bes + Air
Alkali
Alkali
Oksida bes + Asid
Si
Amphoteric oxide + Acid Oksida amfoterik + Asid Oksida amfoterik + Alkali
Salt + Water
Garam + Air
Example / Contoh: MgO + 2HCl MgCl2 + H2O
Salt + Water
Garam + Air
Amphoteric oxide + Alkali
Example / Contoh: Na2O + H2O 2NaOH Basic oxide + Acid
Al Amphoteric oxide / Oksida amfoterik
P
Acidic oxide + Water Oksida asid + Air
Salt + Water
Garam +Air
Example / Contoh: Al2O3 + 6HNO3 2Al(NO3)3 +3H2O Al2O3 + 2NaOH 2NaAlO2 + H2O
S
Cl
Acidic oxide / Oksida asid Acid
Asid
Example / Contoh: SO2 + H2O H2SO3 Acidic oxide + Alkali Oksida asid + Alkali
Salt + Water
Garam + Air
Example / Contoh: SiO2 + 2NaOH Na2SiO3 + H2O
(a) Elements in Period 3 can be classified as metals and non-metals based on basic and acidic properties of their oxides / Unsur Kala 3 boleh dikelaskan sebagai logam dan bukan logam berdasarkan sifat kebesan dan keasidan oksidanya. acid salt (i) Basic oxide is metal oxide that can react with to form and water .
m
asid
membentuk
garam
dan
air
.
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Oksida bes adalah oksida logam yang boleh bertindak balas dengan
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Chemistry Form 4 • MODULE
(ii)
Acidic oxide is non-metal oxide that can react with
alkali
to form
Oksida asid adalah oksida bukan logam yang boleh bertindak balas dengan air .
membentuk
to form
and
alkali
Oksida amfoterik adalah oksida yang boleh bertindak balas dengan air . dan
asid
dan
water .
and
alkali
acid
(iii) Amphoteric oxide is oxide that can react with both
salt
alkali
garam
salt
dan
and
water . garam
untuk membentuk
(b) Complete the following table / Lengkapkan jadual berikut: (i) Reaction with water / Tindak balas dengan air: Oxide
Solubility in water
Oksida
Sodium oxide, Na2O
pH
Type of oxide
pH larutan
Jenis oksida
14
Basic oxide
9
Basic oxide
–
–
–
–
3
Acidic oxide
3
Acidic oxide
White solid dissolve in water
Natrium oksida, Na2O
Pepejal putih larut dalam air
Magnesium oksida, MgO
White solid slightly dissolve in water
Magnesium oksida, MgO
Pepejal putih larut separa dalam air
Aluminium oxide, Al2O3
Insoluble
Aluminium oksida, Al2O3
Tidak larut
Silicon oxide, SiO2
Insoluble
Silikon oksida, SiO2
Tidak larut
Phosphorous oxide, P4O10
White solid dissolve in water
Fosforus oksida, P4O10
Pepejal putih larut dalam air
Sulphur dioxide, SO2
White solid dissolve in water
Sulfur dioksida, SO2
(ii)
Keterlarutan dalam air
Pepejal putih larut dalam air
Reaction between the oxide of elements Period 3 with nitric acid and sodium hydroxide solution: Tindak balas antara oksida unsur Kala 3 dengan asid nitrik dan larutan natrium hidroksida: Observation / Pemerhatian Oxide Oksida
Reaction with dilute nitric acid
Reaction with sodium hydroxide solution
The white solid dissolve to form colourless solution.
No change. The white solid does not dissolve.
Tindak balas dengan asid nitrik cair
Magnesium oxide, MgO Magnesium oksida, MgO
Pepejal putih larut membentuk larutan tanpa warna.
Aluminium oxide, Al2O3 Aluminium oksida, Al2O3
Silicon oxide, SiO2
Tiada perubahan. Pepejal putih tidak larut.
No change. The white solid does not dissolve.
Tiada perubahan. Pepejal putih tidak larut.
Jenis oksida
Tindak balas dengan natrium hidroksida
Tiada perubahan. Pepejal putih tidak larut.
The white solid dissolve to form colourless solution. Pepejal putih larut membentuk larutan tanpa warna.
The white solid dissolve to form colourless solution. Pepejal putih larut membentuk larutan tanpa warna.
Basic oxide
Amphoteric oxide
Acidic oxide
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No change. The white solid does not dissolve.
Type of oxide
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MODULE • Chemistry Form 4
7
Steps to compare and explain the change in atomic size/ radius/ electronegativity across Period 3, reactivity down Group 1 and Group 17: Langkah-langkah untuk membanding dan menerangkan perubahan saiz atom/ jejari/ keelekronegatifan merentasi Kala 3, kereaktifan menuruni Kumpulan 1 dan Kumpulan 17:
16 p
Na
K
(a) To Compare Atomic Size/ Radius and Electronegativity Across Period 3: Membanding Jejari/ Saiz Atom dan Keelektronegatifan Merentasi Kala 3: (i) Compare number of shells in each atom. Bandingkan bilangan petala dalam setiap atom. (ii) Compare number of proton in the nucleus. Bandingkan bilangan proton dalam nukleus. (iii) Compare the strength of attraction from the nucleus to the electrons in the shells . Bandingkan kekuatan tarikan dari proton dalam nukleus kepada elektron dalam petala . (iv) Compare the atomic size/ Compare the electronegativity. Bandingkan saiz atom/ Bandingkan keelektronegatifan. (b) To Compare Reactivity Down Group 1 and Group 17: Membanding Kereaktifan Menuruni Kumpulan 1 dan Kumpulan 17: (i)
Compare number of shells in each atom. Bandingkan bilangan petala dalam setiap atom.
(ii)
Compare the strength of proton in the nucleus to attract valence electron (Group 1)// to attract electron to the outermost shells (Group 17). Bandingkan kekuatan proton dalam nukleus menarik elektron valens (Kumpulan 1) // menarik elektron ke petala paling luar (Kumpulan 17).
(iii) Compare tendency of the atom to release electron (Group 1)// receive electron (Group 17). Bandingkan kecenderungan atom untuk melepaskan elektron (Kumpulan 1) // menerima elektron (Kumpulan 17).
Reactivity decreases down Group 17/Kereaktifan berkurang menurun Kumpulan 17
Reactivity increases down Group 1/Kereaktifan bertambah menurun Kumpulan 1
Li
Atomic radius of the atoms decreases across Period 3 from sodium to chlorine. Jejari atom berkurang merentasi Kala 3 dari natrium kepada klorin.
F
Cl
Br
TRANSITION ELEMENT / UNSUR PERALIHAN 1
Situated between Group 2 and 13. The examples of transition element are Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn. Terletak antara Kumpulan 2 dan 13. Contoh unsur peralihan adalah Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu dan Zn.
2
Show metal properties: Shiny, conducts heat and electricity, malleable, high tensile strength, high melting point and density. Mempunyai sifat logam: Permukaan berkilat, konduktor haba dan elektrik, bersifat mulur, boleh ditempa, kekuatan tegangan yang tinggi, takat lebur dan ketumpatan tinggi. Special characteristics / Ciri istimewa: (a) Form coloured compound / Membentuk sebatian berwarna. Example / Contoh:
3
Iron(III) chloride is brown, iron(II) chloride is green and copper(II) sulphate is blue. Ferum(III) klorida adalah perang, ferum(II) klorida adalah hijau dan kuprum(II) sulfat adalah biru. (b) Form different oxidation numbers / Membentuk nombor pengoksidaan berbeza. (c) Form complex ions: MnO4–, Cr2O72–, CrO42–, etc / Membentuk ion kompleks: MnO4–, Cr2O72–, CrO42–, dan sebagainya. (d) Useful as a catalyst in industries / Berguna sebagai mangkin dalam industri. Example / Contoh: Iron: Haber Process in the manufacture of ammonia / Ferum: Proses Haber dalam penghasilan ammonia.
N2 + 3H2
Fe
2NH3
Vanadium(V) Oxide: Contact Process in the manufacture of sulphuric acid. Vanadium(V) Oksida: Proses Sentuh dalam penghasilan asid sulfurik.
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Platinum: Ostwald Process in the manufacture of nitric acid / Platinum: Proses Ostwald dalam penghasilan asid nitrik.
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Chemistry Form 4 • MODULE
EXERCISE / LATIHAN 1
The diagram below shows the electron arrangement for atoms P and Q. Rajah di bawah menunjukkan susunan elektron bagi atom P dan Q.
P
Q
(a) Elements P and Q are placed in the same group in Periodic Table. State the group. Unsur P dan Q terletak dalam kumpulan yang sama dalam Jadual Berkala. Nyatakan kumpulan itu.
Group 1 (b) How is elements P and Q kept in the laboratory? Give reason for your answer. Bagaimanakah unsur P dan Q disimpan di dalam makmal? Berikan sebab bagi jawapan anda.
In paraffin oil. To prevent them from reacting with oxygen or water vapour in the atmosphere. (c) (i)
Write chemical equation for the reaction between elements P with water. Tuliskan persamaan kimia untuk tindak balas antara unsur P dengan air.
2P + 2H2O
(ii)
2POH + H2
What is the expected change of colour when a few drops of phenolphthalein are added into the aqueous solution of the product? Explain your answer. Apakah perubahan warna yang dijangkakan apabila beberapa titik fenolftalein dititiskan ke dalam larutan akueus yang terhasil? Terangkan jawapan anda.
Colourless to purple/ pink. The solution formed is alkaline. (iii) Between element P and element Q, which is more reactive in the reaction with water? Antara unsur P dan Q, yang manakah lebih reaktif apabila bertindak balas dengan air?
Element Q is more reactive than P. (iv) Explain your answer in (c)(iii) / Terangkan jawapan anda dalam (c)(iii). The size of atom Q is larger than atom P. The valence electron of atom Q is further away from the nucleus compared to atom P. The attraction forces between proton in the nucleus to the valence electron of atom Q is weaker than atom P. Atom Q is easier to release the valence electron compared to atom P. (d) Name one element that has the same chemical properties as P and Q. Namakan satu elemen yang mempunyai ciri-ciri kimia yang sama dengan P dan Q.
Potassium 2
The diagram below shows the information regarding elements W and X which are from the same group in the Periodic Table. Rajah di bawah menunjukkan maklumat mengenai unsur W dan X yang terletak di kumpulan yang sama dalam Jadual Berkala. 19 9
(a) (i) (ii)
W
35 17
X
Write the electron arrangement of atom of elements W and X / Tuliskan susunan elektron bagi atom unsur W dan X. 2.7 2.8.7 Atom W / Atom W : Atom X / Atom X : State the position of elements W and X in the Periodic Table. Nyatakan kedudukan unsur W dan X dalam Jadual Berkala.
Element W / Unsur W : Group 17, Period 2 Element X / Unsur X : Group 17, Period 3
(iii) Do elements W and X show the same chemical property? Explain your answer. Adakah unsur W dan X menunjukkan sifat kimia yang serupa? Terangkan jawapan anda.
Elements W and X have the same chemical property. Atoms W and X have the same number of valence electrons.
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(b) State the type of particles of substances W and X / Nyatakan jenis zarah yang terdapat pada W dan X. Molecule
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MODULE • Chemistry Form 4
(c) (i)
Compare the boiling point of elements W and X. Explain the difference. Bandingkan takat didih unsur W dan X. Terangkan perbezaan itu.
The boiling point of element X is higher than element W. The size of molecule X2 is bigger than molecule W2 . The forces of attraction between molecules X2 is stronger than molecule W2. More heat energy is needed to overcome the stronger forces between molecules. (d) (i)
Element X can react with sodium element to form a compound. Write the chemical equation for the reaction. Unsur X boleh bertindak balas dengan unsur natrium untuk membentuk sebatian. Tulis persamaan kimia untuk tindak balas tersebut.
X2 + 2Na (ii)
2NaX
How does the reactivity of element W and element X differ? Explain your answer. Bagaimanakah kereaktifan unsur W dan X berbeza? Terangkan jawapan anda.
Element W is more reactive than element X. The size of atom W is smaller than atom X. The outermost occupied shell of atom W is nearer to the nucleus compare to atom X. The strength of the nucleus of atom W to attract electron to the outermost shell is stronger than atom X. 3
The table below shows the number of neutron and relative atomic mass of eight elements represented as P, Q, R, S, T, U and W. Jadual di bawah menunjukkan bilangan neutron dan jisim atom relatif bagi lapan unsur yang diwakili oleh huruf P, Q, R, S, T, U, V dan W. Atom / Unsur Number of neutron Bilangan neutron dalam atom
Relative atomic mass Jisim atom relatif
Number of proton Bilangan proton dalam atom
Electron arrangement Susunan elektron dalam atom
P
Q
R
S
T
U
V
W
12
12
14
14
16
16
18
22
23
24
27
28
31
32
35
40
11
12
13
14
15
16
17
18
2.8.1
2.8.2
2.8.3
2.8.4
2.8.5
2.8.6
2.8.7
2.8.8
(a) Complete the above table by writing the number of proton and electron arrangement for the atom of each element. Lengkapkan jadual di atas dengan menulis bilangan proton dan susunan elektron bagi atom setiap unsur.
(b) (i)
State the period of element P – W in the Periodic Table. Explain your answer. Nyatakan kala manakah unsur P – W terletak dalam Jadual Berkala? Terangkan jawapan anda.
Period 3 because P – W atoms have three shells occupied with electrons. (ii)
What is the proton number of another element that is in the same group as P? Nyatakan bilangan proton bagi unsur lain yang sama kumpulan dengan P.
3/19 (c) Write the standard representation for element Q / Tuliskan simbol perwakilan piawai untuk unsur Q. 24 Q 12 (d) Which element exist as / Unsur yang manakah wujud sebagai W monoatomic gas / gas monoatom? (e) (i)
diatomic gas / gas dwiatom?
T/ U/ V
Which element can react vigorously with water to produce hydrogen gas? Unsur yang manakah bertindak balas cergas dengan air untuk menghasilkan gas hidrogen?
P
m
Write the balanced equation for the reaction in (e)(i) / Tuliskan persamaan seimbang untuk tindak balas (e)(i). 2P + 2H2O 2POH + H2
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Chemistry Form 4 • MODULE
(f)
State the arrangement of elements T, U and V in the order of increasing atomic radius. Explain your answer. Nyatakan susunan unsur T, U dan V dalam tertib pertambahan jejari atom. Terangkan jawapan anda.
V, U and T. Atoms of T, U, and V have three shells occupied with electrons. The proton number // positive charges in the nucleus increases from T to V. The forces of attraction between proton in the nucleus and the electrons in the shells increase from T to V. The shells filled with electrons are pulled nearer to the nucleus from T to V. 4
The diagram below shows part of the Periodic Table of Elements. X, Y, A, B, D, E, F and G do not represent the actual symbols. Rajah di bawah menunjukkan sebahagian daripada Jadual Berkala Unsur. X, Y, A, B, D, E, F dan G tidak mewakili simbol yang sebenar. X Y A F
(a) (i) (ii)
B
D
E
G
State the position of element B in the Periodic Table / Nyatakan kedudukan unsur B dalam Jadual Berkala. Period 3, Group 13 Explain your answer in (a)(i) / Terangkan jawapan anda dalam (a)(i). Electron arrangement atom B is 2.8.3. Atom B has three valence electrons, element B is in Group 13. Atom B has three shells occupied with electrons, element B is in Period 3.
(b) (i) (ii)
Which element is monatomic gas / Unsur yang manakah adalah gas monoatom? Element Y Explain your answer in (b)(i) / Terangkan jawapan anda dalam (b)(i). Atom Y has achieved octet electron arrangement // has electron arrangement 2.8.
(c) Choose an element that / Pilih unsur yang: (i)
exists in the form of molecule / wujud dalam bentuk molekul
(ii)
forms acidic oxide / membentuk oksida asid
(iii)
has atoms that have no neutron / atom yang tiada neutron
(iv)
is an alkali metal / logam alkali
(v)
forms amphoteric oxide / membentuk oksida amfoterik
B
(vi)
has a proton number of 15 / mempunyai nombor proton 15
C
(vii) is most electropositive / paling elektropositif (viii) forms basic oxide / membentuk oksida bes (ix)
forms coloured compound / membentuk sebatian berwarna
X/D/E D/E X A/F
F A/F G
(d) Arrange Y, A, B, D and E according to the order of increasing atomic size. Susun Y, A, B, D dan E mengikut tertib pertambahan saiz atom.
Y, E, D, B, A (e) (i) (ii)
Write the electron arrangement for an atom of element / Tulis susunan elektron bagi atom unsur: 2.8.5 2.8.7 D: E: Compare electronegativity of elements D and E / Bandingkan keelektronegatifan unsur D dan E. Element E is more electronegative than element D.
(iii) Explain your answer in (e)(ii) / Terangkan jawapan anda dalam (e)(ii). Atoms E and D have the same number of shells occupied with electrons. The number of proton in the nucleus of atom E is more than atom D. The strength of proton in nucleus to attract electrons to the outermost shells n io
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MODULE • Chemistry Form 4
Objective Questions / Soalan Objektif 1
Proton number of element P is 8. What is the position of this element in the Periodic Table of Elements?
Period / Kala
16
2
A
2
B
16
3
C
18
2
D
18
3
Potassium reacts with element Q from Group 17 in Periodic Table. Which of the following chemical equations is correct? Kalium bertindak balas dengan unsur Q dalam Kumpulan 17 dalam Jadual Berkala Unsur. Antara persamaan kimia berikut, yang manakah betul?
A K + Q KQ B K+ + Q – KQ 3
C 2K + Q2 2KQ D K + Q2 KQ2
Y oxide
Z oxide
A
Amphoteric
Acidic
Basic
Amfoterik
Asid
Bes
B
Amphoteric
Basic
Acidic
Amfoterik
Bes
Asid
C
Acidic
Amphoteric
Basic
Asid
Amfoterik
Bes
D
Acidic
Acidic
Basic
Asid
Asid
Bes
Oksida X
Nombor proton unsur P adalah 8. Apakah kedudukan unsur P dalam Jadual Berkala Unsur?
Group/Kumpulan
X oxide
6
Jadual di bawah menunjukkan sifat oksida unsur X, Y dan Z yang berada dalam Kala 3 Jadual Berkala Unsur.
X Y Z
Antara pernyataan berikut, yang manakah benar?
I II
A B C D 5
Calcium / Kalsium III Potassium / Kalium Sulphur / Sulfur IV Nitrogen / Nitrogen I and II only / I dan II sahaja I and III only / I dan III sahaja II and IV only / II dan IV sahaja III and IV only / III dan IV sahaja
The diagram below shows the standard representation for elements X, Y and Z.
– Oxide of Z reacts with sodium hydroxide solution. Oksida Z bertindak balas dengan larutan natrium hidroksida.
– Oxide of Z reacts with nitric acid.
A All the elements can conduct electricity.
Antara berikut, yang manakah dapat membentuk oksida asid?
Oksida Y bertindak balas dengan larutan natrium hidroksida.
Oksida Y tidak bertindak balas dengan asid nitrik.
Z
Which of the following elements can form acidic oxide?
– Oxide of Y reacts with sodium hydroxide solution. – Oxide of Y does not react with nitric acid
Which of the following statements is true?
4
Oksida X bertindak balas dengan asid nitrik.
natrium hidroksida.
Y
D
– Oxide of X reacts with nitric acid.
– Oxide of X does not react with sodium hydroxide solution./Oksida X tidak bertindak balas dengan larutan
Rajah di bawah menunjukkan kedudukan unsur X, Y dan Z dalam Jadual Berkala Unsur.
C
Property of the oxide formed Sifat oksida yang terbentuk
Element Unsur
The diagram below shows the position of elements X, Y and Z in the Periodic Table.
B
Oksida Z
The table below shows the properties of the oxide of elements X, Y and Z which are located in Period 3 of the Periodic Table.
X
Semua unsur boleh mengkonduksi elektrik. All the elements exist as gas at room temperature. Semua unsur wujud dalam bentuk gas pada suhu bilik. The boiling points of the elements increase from X Y Z. Takat didih unsur bertambah dari X → Y → Z. The density of the elements decreases going down from X Y Z. Ketumpatan unsur berkurang dari X → Y → Z.
Oksida Y
Oksida Z bertindak balas dengan asid nitrik.
What is the correct arrangement of elements X, Y and Z from left to right in Period 3 of the Periodic Table? Apakah susunan yang betul bagi unsur X, Y dan Z dari kiri ke kanan Kala 3 Jadual Berkala Unsur?
A Z, X, Y B X, Z, Y 7
C X, Y, Z D Y, Z, X
The following statements describe the characteristic of an element: Pernyataan berikut menerangkan sifat suatu unsur.
– Used as a catalyst / Digunakan sebagai mangkin. – Forms coloured ions or compound. Membentuk ion atau sebatian berwarna.
– Shows different oxidation number in its compound. Menunjukkan numbor pengoksidaan yang berbeza.
Which of the following is the position of the element in the Periodic Table of Element? Antara berikut, yang manakah adalah kedudukan unsur tersebut dalam Jadual Berkala Unsur?
Rajah di bawah menunjukkan simbol unsur X, Y dan Z. 27 13
X
32 16
Y
23 11
Z
What type of oxides are formed by X, Y and Z? m
A B
C
D
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Chemistry Form 4 • MODULE
8
The table below shows the proton number of elements in Period 3 of the Periodic Table of Elements. Jadual di bawah menunjukkan nombor proton unsur dalam Kala 3 Jadual Berkala Unsur.
10 The table below shows the proton numbers of elements X and Y.
Jadual di bawah menunjukkan nombor proton unsur X dan Y.
Elements / Unsur
Proton number / Nombor proton
Jejari (nm)
X
11
11
0.191
Y
19
Mg
12
0.160
Which statements are true about elements X and Y?
Al
13
0.130
Antara pernyataan berikut, yang manakah benar tentang unsur X dan Y?
Si
14
0.118
I
P
15
0.110
S
16
0.102
Cl
17
0.099
Ar
18
0.095
Elements
Proton number
Radius (nm)
Na
Unsur
Nombor proton
II III IV
Why does the atomic radius of the atoms decrease from sodium to argon in the period? Mengapakah saiz atom berkurang dari natrium ke argon dalam kala?
A The number of valence electrons increases. Bilangan elektron valens bertambah. The electronegativity of the elements increases. Keelektronegatifan unsur bertambah. The properties of the elements change from metallic to non-metallic. Sifat unsur berubah dari logam kepada bukan logam. The strength of attraction of the nucleus to the electrons in the shells increases. Kekuatan tarikan nukleus kepada elektron dalam petala bertambah.
B C D
9
A B C D
Atoms X and Y have one valence electron. Atom X dan Y mempunyai satu elektron valens. Elements X is more reactive than element Y. Unsur X lebih reaktif daripada unsur Y. Atom X has a bigger atomic size than atom Y. Saiz atom X lebih besar daripada saiz atom Y. Elements X and Y are in the same group in the Periodic Table. Unsur X dan Y berada dalam kumpulan sama dalam Jadual Berkala. I and III only / I dan III sahaja I and IV only / I dan IV sahaja II and III only / II dan III sahaja II and IV only / II dan IV sahaja
The table below shows proton number for elements P, Q and R. Jadual di bawah menunjukkan nombor proton bagi unsur P, Q dan R.
Elements / Unsur
Proton number / Nombor proton
P
11
Q
17
R
19
Which of the following statements about these elements are true? Antara pernyataan berikut, yang manakah benar tentang unsur-unsur tersebut?
I II III IV
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P and R has the lowest number of valence electrons. P dan R mempunyai bilangan elektron valens paling rendah. P and R have similar chemical properties. P dan R mempunyai sifat kimia yang sama. Size of atom R is bigger than size of atom Q. Saiz atom R lebih besar daripada saiz atom Q. Element R is more electronegative than element Q. Unsur R lebih elektronegatif daripada unsur Q. I, II and III / I, II dan III I, II dan IV / I, II dan IV I, III dan IV / I, III dan IV II, III dan IV / II, III dan IV
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MODULE • Chemistry Form 4
CHEMICAL BOND
4
IKATAN KIMIA
TYPE OF CHEMICAL BOND / JENIS IKATAN KIMIA • IONIC BOND / IKATAN ION – To predict the formulae of ionic compounds based on the electron arrangement. Meramal formula sebatian ion berdasarkan susunan elektron. – To describe the formation of ionic bond / Menghuraikan pembentukan ikatan ion. – To draw the diagram of the formation of ionic bond / Melukis rajah pembentukan ikatan ion. • COVALENT BONDS / IKATAN KOVALEN – To predict the formulae of molecules of elements or covalent compounds as well as the types of covalent bond. Meramal formula molekul unsur atau molekul sebatian kovalen serta jenis ikatan kovalen. – To describe the formation of covalent bonds / Menghuraikan pembentukan ikatan kovalen. – To draw the diagram of the formation of covalent bonds / Melukis rajah pembentukan ikatan kovalen.
PROPERTIES OF IONIC AND COVALENT COMPOUNDS / SIFAT SEBATIAN ION DAN KOVALEN • IONIC COMPOUNDS / SEBATIAN ION – To state and explain the properties from the aspect of melting point and electrical conductivity in solid and molten state. Menyatakan dan menerangkan sifat dari segi takat lebur, kekonduksian elektrik dalam keadaan pepejal dan leburan. • COVALENT COMPOUNDS / SEBATIAN KOVALEN – To state the solubility in water and organic solvents / Menyatakan keterlarutan dalam air dan pelarut organik. – To differentiate between ionic and covalent compounds / Membezakan sebatian ion dengan sebatian kovalen.
CHEMICAL BONDS BETWEEN ATOMS / IKATAN KIMIA ANTARA ATOM
Chemical bonds are formed when two or more atoms of elements bond together. Atoms form chemical bonds to achieve a stable duplet or octet electron arrangement. There are two types of chemical bond, that is Ionic Bond and Covalent Bond.
1
Ikatan kimia dibentuk apabila dua atau lebih atom-atom unsur berpadu. Atom-atom membentuk ikatan kimia untuk mencapai susunan elektron yang stabil iaitu susunan elektron duplet atau oktet. Terdapat dua jenis ikatan kimia iaitu Ikatan Ion dan Ikatan Kovalen.
IONIC BOND / IKATAN ION
Ionic bond is formed between atoms of metal elements that release electrons to atoms of non-metal elements.
1
Ikatan ion terbentuk antara atom unsur logam yang melepaskan elektron kepada atom unsur bukan logam yang menerima elektron.
Atom of an element is neutral because the number of protons is equal to the number of electrons.
2
Atom suatu unsur adalah neutral kerana bilangan proton adalah sama dan dengan bilangan elektron.
Atoms of elements that release the electrons form positive ions and atoms that receive the electrons form negative ions to achieve a stable octet or duplet electron arrangement:
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Chemistry Form 4 • MODULE
Complete the following table / Lengkapkan jadual di bawah: Changes
Na
Na+ + e
Ca
Electron arrangement
2.8.1
2.8
2.8.2
Total of positive charges (From number of proton)
+11
+11
Total of negative charges (From number of proton)
–11
Perubahan
Ca2+ + 2e
O + 2e
O2–
Cl + e
Cl–
2.8
2.6
2.8
2.8.7
2.8.8
+12
+12
+8
+8
+17
+17
–10
–12
–10
–8
–10
–17
–18
0
+1
0
+2
0
–2
0
–1
Sodium atom
Sodium ion
Calcium atom
Oxygen atom
Oxide ion
Chlorine atom
Susunan elektron
Jumlah cas positf (Dari bilangan proton)
Jumlah cas negaitf (Dari bilangan proton)
Total changes Jumlah cas
Type of particles Jenis zarah
Atom natrium
3
Atom kalsium
Calcium ion
Atom oksigen
Atom klorin
Chlorine ion
The positive ions and negative ions are attracted to one another with strong electrostatic forces. The electrostatic force between the positive and negative ions forms ionic bond. Ion positif dan ion negatif tertarik antara satu sama lain dengan daya elekrostatik yang kuat. Daya elektrostatik antara ion positif dan ion negatif membentuk ikatan ion.
4
Ionic bond is usually formed between atoms from Groups 1, 2 and 13 (metal) with atoms from Groups 15, 16 and 17 (non-metal). Ikatan ion biasanya dibentuk antara atom-atom daripada Kumpulan 1, 2 dan 13 (logam) dengan atom-atom dari Kumpulan 15, 16 dan 17 (bukan logam).
5
The maximum number of electrons transferred in the formation of ionic bond is usually three: Bilangan maksimum elektron yang berpindah dalam pembentukan ikatan ion biasanya tiga.
(a) Atoms of elements in Groups 1, 2 and 13 release 1, 2 and 3 electrons respectively to form positively charged ions (+1, +2 and +3). Atom unsur Kumpulan 1, 2 dan 13 masing masing melepaskan 1, 2 dan 3 elektron membentuk ion bercas positif (+1, +2 dan +3).
(b) Atoms of elements in Groups 15, 16 and 17 receive 3, 2 and 1 electrons respectively to form negatively charged ions (–3, –2 and –1) Atom unsur Kumpulan 15, 16 dan 17 masing-masing menerima 3, 2 dan 1 elektron membentuk ion bercas negatif (–3, –2 dan –1). 6
Examples / Contoh-contoh: (i) Sodium chloride / Natrium klorida Predict the formula / Ramal formula: Element
Proton number
Electron arrangement
Na
11
2.8.1
Cl
17
2.8.7
Unsur
Nombor proton
Susunan elektron
Na Cl + e
Na+ + e Cl–
Na+
Cl–
1
1
NaCl
Draw the electron arrangement of the compound formed. Lukiskan susunan elektron bagi setiap sebatian yang terbentuk.
Transfer Pindah Na Na
C1 Cl
Na Na
C1 Cl
Sodium atom, Na Atom natrium, Na
Chlorine atom,Cl Cl Atom klorin,
Sodium ion, Na Ion natrium, Na +
Chloride ion,Cl Cl– Ion klorida,
–
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Explanation / Penerangan:
2.8.1
(a) Electron arrangement of sodium atom is stable Therefore sodium atom is not
one
. Sodium atom has one . Sodium atom releases
octet electron arrangement to form sodium ion , Na+ with electron arrangement
valence electron.
electron to achieve a stable 2.8 .
2.8.1 . Atom natrium mempunyai satu elektron valens. Dengan itu atom Susunan elektron atom natrium ialah stabil . Atom natrium melepaskan satu elektron ini untuk mencapai susunan elektron oktet yang natrium tidak stabil membentuk ion
natrium , Na+ dengan susunan elektron
2.8
.
2.8.7
seven (b) Electron arrangement of chlorine atom is . Chlorine atom has valence electrons. one Chlorine atom receives electron to achieve stable octet electron arrangement to form chlorine
2.8.8
ion, Cl– with an octet arrangement of electron 2.8.7
Susunan elektron bagi atom klorin ialah
. tujuh
. Atom klorin mempunyai elektron valens. Atom klorin satu elektron membentuk ion klorida , Cl– dengan
mencapai susunan elektron oktet yang stabil dengan menerima 2.8.8 . susunan elektron
(c)
Sodium ions , Na+ and chloride ions , Cl– ions are attracted with strong bond formed is called ionic bond. Ion natrium , Na+ dan ikatan ion.
electrostatic
force. The
ion klorida , Cl– ditarik dengan daya elektrostastik yang kuat. Ikatan yang terbentuk dinamakan
(ii) Magnesium oxide / Magnesium oksida Predict the formula / Ramal formula: Element
Proton number
Electron arrangement
Mg
12
2.8.2
O
8
2.6
Unsur
Nombor proton
Susunan elektron
Mg Mg+ + 2e O + 2e O2–
Draw the electron arrangement of the compound formed.
Mg2+
O2–
2
2
1
1
MgO
Lukiskan susunan elektron bagi setiap sebatian yang terbentuk. 2+
Mg Mg
Pindah Transfer
Magnesium atom, Mg Atom magnesium, Mg
O O
2−
O O
Mg Mg
Oxygen atom, OO Atom oksigen,
Magnesium ion, Mg Mg 2+ Ion magnesium, 2+
2– 2− Oxide ion, OO Ion oksida,
Explanation / Penerangan:
2.8.2 (a) The electron arrangement of magnesium atom is . Magnesium atom has stable electrons. Therefore magnesium atom is not . Magnesium atom releases electrons to achieve a stable octet electron arrangement to form 2.8 arrangement .
magnesium ion , Mg
2+
two
valence
2
valence
with electron
2.8.2 . Atom magnesium mempunyai dua elektron di petala terluar. Maka atom Susunan elektron atom magnesium stabil dua . Atom magnesium melepaskan elektron valens untuk mencapai susunan elektron oktet magnesium tidak yang stabil membentuk
ion magnesium , Mg2+ dengan susunan elektron
2.8
.
2.6 (b) The electron arrangement of oxygen atom is . Oxygen atom is also unstable. Oxygen atom receives two electrons to achieve a stable octet electron arrangement to form oxide ion , O2– with electron arrangement
2.8
Susunan elektron atom oksigen ialah
. 2.6
. Atom oksigen juga tidak stabil, atom oksigen
m
ion oksida
menerima
, O dengan susunan elektron
dua elektron 2.8
.
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2–
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Chemistry Form 4 • MODULE
(c)
Magnesium ion , Mg2+ and formed is called ionic bond. Ion magnesium , Mg2+ dan dinamakan ikatan ion.
oxide ion , O2– are attracted by strong
ion oksida
electrostatic
force. The bond
, O2– ditarik dengan daya elektrostatik yang kuat. Ikatan yang terbentuk
(iii) Magnesium chloride /Magnesium klorida Predict the formula / Ramal formula: Element
Proton number
Electron arrangement
Mg
12
2.8.2
Cl
17
2.8.7
Unsur
Nombor proton
Mg Cl + e
Susunan elektron
Mg2+ + 2e Cl–
Mg2+
Cl–
1
2
MgCl2
Draw the electron arrangement of the compound formed. Lukiskan susunan elektron bagi setiap sebatian yang terbentuk. 2+
Transfer Pindah
Transfer Pindah Mg
C1
Chlorine atom, Atom klorin, Cl Cl
C1
Magnesium atom,Mg Mg Atom magnesium,
Mg
C1
Chlorine atom, Atom klorin, Cl Cl
C1
Chlorine ion,ClCl– Ion Magnesium ion,Mg Mg2+2+ Ion Chlorine ion, Ion klorida, magnesium, klorida, ClCl–
Explanation / Penerangan:
2.8.2
(a) The electron arrangement of magnesium atom is
2 . Magnesium atom has stable . Magnesium atom releases
in the outer shell. Therefore, magnesium atom is not
valence electrons to achieve a stable octet electron arrangement to form 2.8 electron arrangement .
electrons 2
magnesium ion , Mg2+ with
2.8.2 . Atom magnesium mempunyai 2 elektron di petala terluar. Maka atom Susunan elektron atom magnesium stabil 2 . Atom magnesium melepaskan elektron valens untuk mencapai susunan elektron oktet magnesium tidak ion magnesium , Mg2+ dengan susunan elektron
yang stabil membentuk
2.8
.
2.8.7 (b) The electron arrangement of chlorine atom is . Chlorine atom is also unstable. Chlorine atom receives one electron to achieve a stable octet electron arrangement to form chloride ion , Cl– with electron arrangement
2.8.8
Susunan elektron atom klorin ialah
. 2.8.7
ion klorida , Cl dengan susunan elektron
mencapai susunan elektron oktet yang stabil membentuk
(c) As such, Oleh itu,
one satu
Daya
elektrostatik
–
magnesium atom releases atom magnesium melepaskan
(d) Strong electrostatic ionic bond.
menerima
. Atom klorin juga tidak stabil. Atom klorin
2
force is formed between
yang kuat terbentuk antara
2
2
electrons to
elektron kepada
2
2.8.8
.
chlorine atoms. atom klorin.
magnesium ion , Mg
ion magnesium , Mg2+ dan
satu elektron untuk
2+
and
chloride ion , Cl– to form
ion klorida , Cl– membentuk ikatan ionik.
COVALENT BONDS / IKATAN KOVALEN 1
This bond is formed when two or more similar or different atoms share valence electrons between them, so that each atom achieves the octet or duplet electron arrangement that is a stable electron arrangement for noble gases. Ikatan ini terbentuk apabila dua atau lebih atom yang sama atau berlainan berkongsi elektron valens antara satu sama lain supaya setiap atom mencapai susunan elektron oktet atau duplet iaitu susunan elektron gas adi yang stabil.
2
Normally, this bond is formed when similar or different non-metal atoms bond together. [Atoms from Groups 14, 15, 16 and 17] n io
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Ikatan ini biasanya terbentuk apabila atom-atom bukan logam berpadu. [Atom-atom dari Kumpulan 14, 15, 16 dan 17]
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MODULE • Chemistry Form 4
When atoms of non-metals share their valence electrons from their outermost shells to achieve stable duplet or octet sharing atoms electron arrangement, covalent bonds are formed. The product of the of electrons between
3
is called
molecule .
Apabila atom-atom bukan logam berkongsi elektron pada petala terluar untuk mencapai susunan elektron duplet atau oktet yang stabil, ikatan kovalen terbentuk. Hasil daripada perkongsian elektron antara atom-atom ini membentuk molekul .
The molecules are neutral as there is no electron transfer involved. During the formation of covalent bonding , each atom contributes same number of electrons for sharing. The number of electrons shared can be one pair, two pairs or three pairs.
4
neutral kerana tidak melibatkan pemindahan elektron. Semasa pembentukan ikatan kovalen , setiap atom akan Molekul adalah menyumbang bilangan elektron yang sama untuk dikongsi. Bilangan elektron yang dikongsi boleh jadi sepasang, dua pasang atau tiga pasang.
The forces that exist between molecules are Van der Waals forces that are weak. These forces become stronger when the molecule size increases.
5
Daya yang wujud antara molekul adalah
daya Van der Waals
yang lemah. Daya ini semakin kuat apabila saiz molekul bertambah.
Examples / Contoh: (i) Hydrogen molecule / Molekul hidrogen: (a) Hydrogen atom has one electron in the first shell, with an electron arrangement of 1 needs one electron to achieve a stable duplet electron arrangement.
6
Atom hidrogen mempunyai satu elektron pada petala pertama dengan susunan elektron 1 memerlukan satu elektron untuk mencapai susunan elektron duplet yang stabil.
(b)
Two hydrogen atoms share a pair of electrons to form a hydrogen molecule. Dua atom hidrogen berkongsi sepasang elektron membentuk satu molekul hidrogen.
(c)
Both hydrogen atoms achieve a stable duplet arrangement of electron. Kedua-dua atom hidrogen mencapai susunan elektron duplet yang stabil.
Draw the electron arrangement of the compound formed / Lukiskan susunan elektron bagi sebatian yang terbentuk. Share
Kongsi Kongsi Share
H H
H
H H
H
The number of electron pairs shared is
one
pair. Single covalent bond is formed.
Bilangan pasangan elektron dikongsi adalah
satu
pasang. Ikatan kovalen tunggal terbentuk.
(ii) Oxygen molecule / Molekul oksigen: (a)
Oxygen atom with an electron arrangement 2.6 needs two electrons to achieve a stable arrangement. Atom oksigen dengan susunan elektron 2.6 memerlukan dua elektron untuk mencapai susunan elektron
(b)
Two oxygen atoms share
octet oktet
electron yang stabil.
two
pairs of electrons to achieve a stable octet arrangement of electron, form an oxygen molecule. Each oxygen atom achieves stable octet electron arrangement. dua
pasang elektron untuk mencapai susunan elektron oktet yang stabil, membentuk satu oktet yang stabil. molekul oksigen. Setiap atom oksigen mencapai susunan elektron Dua atom oksigen berkongsi
Draw the electron arrangement of the compound formed / Lukiskan susunan elektron bagi sebatian yang terbentuk.
O O
Kongsi Share
m
Oxygen atom, OO Atom oksigen,
O O
O
Oxygen molecule, O22 Molekul oksigen, O
The number of electron pairs shared is
2
pairs. Double covalent bond is formed.
Bilangan pasangan elektron dikongsi adalah
2
pasang. Ikatan kovalen ganda dua terbentuk.
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O O
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Chemistry Form 4 • MODULE
(iii) Nitrogen molecule / Molekul nitrogen: (a)
3
Atom nitrogen dengan susunan elektron 2.5 memerlukan stabil.
(b)
3
Nitrogen atom with an electron arrangement 2.5 needs arrangement.
electrons to achieve stable
elektron untuk mencapai susunan elektron
octet oktet
yang
3
pairs of electrons to achieve a stable octet arrangement, form a nitrogen molecule. Each nitrogen atom achieves stable octet electron arrangement. Two nitrogen atoms share
3
oktet pasang elektron untuk mencapai susunan elektron oktet yang stabil. satu molekul nitrogen. Setiap atom nitrogen mencapai susunan elektron Dua atom nitrogen berkongsi
yang stabil membentuk
Draw the electron arrangement of the compound formed / Lukiskan susunan elektron bagi sebatian yang terbentuk. Share Kongsi
N Nitrogen atom, N N Atom nitrogen,
N
N N
Nitrogen atom, NN Atom nitrogen,
N N
Nitrogen Molekulmolecule, nitrogen,NN2 2
The number of electron pairs shared is
3
pairs. Triple covalent bond is formed.
Bilangan pasangan elektron dikongsi adalah
3
pasang. Ikatan kovalen ganda tiga terbentuk.
(iv) Hydrogen chloride molecule /Molekul hidrogen klorida Predict the formula / Ramal formula: Element
Proton number
Electron arrangement Susunan elektron
H
H
1
1
Cl
Cl
17
2.8.7
Unsur
Nombor proton
needs
1 electron
perlu
1 elektron
needs 1 electron 1 elektron
perlu
Cross the number of electrons each atom needs: HCl Silangkan bilangan elektron yang diperlukan oleh setiap atom: HCl
Draw the electron arrangement of the compound formed. Lukiskan susunan elektron bagi setiap sebatian yang terbentuk.
H
Share Kongsi
Hydrogen atom, H H Atom hidrogen,
H H
Cl C1
Chlorine atom, Atom klorin, ClCl
Cl C1
Hydrogen chloride molecule, HCl Molekul hidrogen klorida, HCl
Explanation / Penerangan:
(a)
Hydrogen atom with an electron arrangement duplet electron arrangement. Atom
hidrogen dengan susunan elektron
1
1
memerlukan
needs satu
one
electron to achieve a stable
elektron untuk mencapai susunan elektron
duplet yang stabil.
(b)
Chlorine atom with an electron arrangement 2.8.7 needs electron arrangement. Atom
klorin dengan susunan elektron 2.8.7 memerlukan yang stabil.
(c)
One chloride Satu
one chlorine atom share molecule with the formula atom klorin berkongsi
HCl
electron to achieve stable
elektron untuk mencapai susunan elektron
pair of electrons with HCl . pasang elektron dengan
one satu
octet oktet
hydrogen atom to form hydrogen atom hidrogen membentuk
molekul
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hidrogen klorida dengan formula
satu
satu
one
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MODULE • Chemistry Form 4
(d)
One chlorine atom contributes electron for sharing. Satu
satu
atom klorin menyumbang dikongsi bersama.
One
(e)
Satu
(f)
Chlorine duplet Atom
one
chlorine atom forms
one
atom klorin membentuk
satu
atom
hydrogen atom contributes one
atom hidrogen menyumbang satu elektron untuk
single covalent bond with
one
hydrogen atom.
ikatan kovalen tunggal dengan
satu
atom hidrogen.
electron arrangement and hydrogen
atom
achieves stable
electron arrangement. oktet
klorin mencapai susunan elektron
duplet
satu
elektron dan
octet
achieves stable
one
electron and
atom
yang stabil dan
hidrogen mencapai susunan elektron
yang stabil.
(v) Water molecule /Molekul air Predict the formula / Ramal formula: Element
Proton number
Electron arrangement Susunan elektron
H
H
1
1
O
O
8
2.6
Unsur
Nombor proton
needs
1 electron
perlu
1 elektron
needs 2 electrons 2 elektron
perlu
Cross the number of electrons each atom needs: H2O
Silangkan bilangan elektron yang diperlukan oleh setiap atom: H2O
Draw the electron arrangement of the compound formed. Lukiskan susunan elektron bagi setiap sebatian yang terbentuk.
H
Kongsi Share
Hydrogen atom, H Atom hidrogen,
Kongsi Share
O O
Oxygen atom, OO Atom oksigen,
H H
H H
Hydrogen atom, H Atom hidrogen,
O O
H H
Water molecule, O Molekul air, HHO 2 2
Explanation / Penerangan:
(a)
Hydrogen atom with an electron arrangement electron arrangement. Atom
1
hidrogen dengan susunan elektron
1
memerlukan
needs electron to achieve a stable satu
duplet
elektron untuk mencapai susunan elektron
duplet yang stabil.
(b)
(c)
Oxygen octet
atom
with an electron arrangement
two
needs
electrons to achieve stable
electron arrangement.
Atom
oksigen dengan susunan elektron
oktet
yang stabil.
One
oxygen atom share molecule with the formula
2.6
two
Satu
atom oksigen berkongsi air dengan formula H2O .
(d)
2.6
memerlukan
dua
pairs of electrons with
H2O
.
dua
pasang elektron dengan
One
two
oxygen atom contributes electron for sharing to form single
elektron untuk mencapai susunan elektron
two dua
hydrogen atoms form water atom hidrogen membentuk
molekul
electrons and each of the two hydrogen atoms contributes one
covalent bond.
Satu
dua
atom oksigen menyumbang elektron dan setiap satu daripada dua atom hidrogen menyumbang satu dikongsi bersama membentuk ikatan kovalen tunggal. elektron untuk
(e)
One Satu
(f)
Oxygen duplet
m
atom oksigen membentuk
atom
achieves stable
single covalent bonds with
dua
ikatan kovalen tunggal dengan
octet
two dua
hydrogen atoms. atom hidrogen.
electron arrangement and hydrogen
atom
achieves
electron arrangement. oksigen mencapai susunan elektron
oktet
yang stabil dan
atom
hidrogen mencapai susunan elektron
duplet yang stabil.
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Chemistry Form 4 • MODULE
(vi) The molecule formed between carbon and chlorine /Molekul yang terbentuk antara karbon dan klorin Predict the formula / Ramal formula: Element
Proton number
Electron arrangement Susunan elektron
C
C
6
2.4
Cl
Cl
17
2.8.7
Unsur
Nombor proton
needs
Cross the number of electrons each atom needs: CCl4
4 electrons
perlu
4 elektron
Silangkan bilangan elektron yang diperlukan oleh setiap atom: CCl4
1 electron
needs
1 elektron
perlu
Draw the electron arrangement of the compound formed. Lukiskan susunan elektron bagi setiap sebatian yang terbentuk.
Cl
Cl
Cl
Cl
Explanation / Penerangan:
(a)
(b)
(c)
Carbon octet
atom
karbon dengan susunan elektron
oktet
yang stabil.
atom
2.4
empat
memerlukan
with an electron arrangement
klorin dengan susunan elektron
oktet
yang stabil.
2.8.7
2.8.7
memerlukan
satu
four carbon atom share pairs of electrons with CCl4 . tetrachloromethane molecule with the formula atom karbon berkongsi empat tetraklorometana berformula CCl4 .
four
elektron untuk mencapai susunan elektron
one
needs
One
One
electrons to achieve a stable
electron to achieve a stable
electron arrangement..
Atom
Satu
(d)
four
needs
electron arrangement.
Atom
Chlorine octet
2.4
with an electron arrangement
pasang elektron dengan
elektron untuk mencapai susunan elektron
four empat
four carbon atom contributes electrons and each of the electron for sharing to form single covalent bond.
chlorine atoms to form atom klorin membentuk
four
chlorine atoms contributes
Satu
satu atom karbon menyumbang empat elektron dan setiap daripada empat satu elektron untuk dikongsi bersama membentuk ikatan kovalen tunggal . menyumbang
(e)
One Satu
(f)
carbon atom forms atom karbon membentuk
Carbon and chlorine
atoms
empat
single covalent bonds with ikatan kovalen tunggal dengan
achieve stable
octet
karbon dan atom klorin mencapai susunan elektron
four empat
atom klorin
chlorine atoms. atom klorin.
electron arrangement. oktet
yang stabil.
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Atom
four
molekul
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MODULE • Chemistry Form 4
7
Comparing the Formation of Ionic and Covalent Bonds / Perbandingan Pembentukan Ikatan Ion dan Kovalen Ionic Bond / Ikatan Ion
Covalent Bond / Ikatan Kovalen
Type of element involved
Between metals (Groups 1, 2 and 13) and non-metals (Groups 15, 16 and 17).
Electron
Electron is released by metal atoms and received by non-metal atoms (electron transfer).
Jenis unsur terlibat
Elektron
Jenis zarah yang dihasilkan
How to predict the formulae
Antara bukan logam 14, 15, 16 dan 17).
logam (Kumpulan 1, 2 dan 13) dengan Antara bukan logam (Kumpulan 15, 16 dan 17).
Elektron dilepaskan oleh atom logam dan atom bukan logam (elektron berpindah).
Type of particle produced
Between non-metal 14, 15, 16 and 17).
diterima
oleh
Metal atom forms positive ion. Non-metal atom forms negative ion. positif . Atom logam membentuk ion negatif Atom bukan logam membentuk ion
different
dengan
non-metals
(Groups
bukan logam
(Kumpulan
of electrons are shared non-metal atoms.
Pasangan elektron dikongsi sama atau berlainan.
by the same or
oleh atom-atom bukan logam
Neutral molecule . Molekul
yang neutral.
.
Determine the coefficient of the charge of the ions and criss cross. Tentukan pekali cas pada ion dan silangkan.
Determine the number of electrons is needed to achieve stable duplet or octet electron arrangement and criss cross. Tentukan bilangan elektron yang diperlukan untuk mencapai susunan elektron duplet atau oktet yang stabil dan silangkan.
Bagaimana meramal formula
Example of electron arrangement in the particles
Pairs
and
+
A
2–
E
+
A
Contoh susunan elektron dalam zarah
Strong electrostatic forces between ions Daya elektrostatik yang kuat antara ion
Strong covalent bond between atoms in the molecules
Example of ionic and covalent compounds
m
# Covalent bond is the shared pairs of electrons between atoms in a molecule. # Ikatan kovalen terhasil daripada perkongsian pasangan elektron antara atom-atom dalam molekul.
Lead(II) bromide, PbBr2
Naphthalene, C8H10
Sodium chloride, NaCl
Acetamide, CH3CONH2
Copper(II) sulphate, CuSO4
Hexane, C6H14
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Contoh sebatian ion dan kovalen
Ikatan kovalen yang kuat antara atom dalam molekul
# Ionic bond is the strong electrostatic force of attraction between positively charged ion and negatively charged ion. # Ikatan ion terhasil daripada daya tarikan elektrostatik yang kuat antara ion bercas positif dan ion bercas negatif.
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Chemistry Form 4 • MODULE
PHYSICAL PROPERTIES OF IONIC AND COVALENT COMPOUND SIFAT FIZIK SEBATIAN ION DAN KOVALEN Ionic compound / Sebatian ion Example
Covalent compound / Sebatian kovalen
Sodium chloride, NaCl / Natrium klorida, NaCl
Carbon dioxide, CO2 / Karbon dioksida, CO2
Contoh
Weak Van der Waals forces between molecules
Daya Van der Waals yang lemah antara molekul
Strong electrostatic forces between positive and negative ions Daya elektrostatik yang kuat antara ion
Strong covalent bond between atoms in the molecules Ikatan kovalen yang kuat antara atom dalam molekul
Type of forces between particles
Strong electrostatic force between ions.
Melting and boiling points
–
Weak Van der walls forces (intermolecular force) between molecule.
Daya elekrostatik yang kuat antara ion.
Daya Van der Waals yang lemah antara molekul.
Jenis daya antara zarah
Takat lebur dan takat didih
High
melting and boiling points because positive ions and negative ions are attracted by strong electrostatic force . Takat lebur dan takat didih tinggi kerana ion positif dan ion negatif ditarik oleh daya tarikan elektrostatik yang kuat.
–
Large amount of energy is needed to overcome it. Banyak tenaga haba diperlukan untuk
– Low melting and boiling points because of the weak “Van der Waals” force between molecules. Takat lebur/takat didih rendah kerana daya "Van der Waals" yang lemah antara molekul.
–
Small
amount of energy is needed to overcome it. Sedikit
mengatasinya .
tenaga haba diperlukan untuk
mengatasinya .
– Giant molecules such as silicon dioxide have very high melting and boiling points. Molekul raksaksa seperti silikon dioksida mempunyai takat didih dan lebur yang amat tinggi.
Electrical conductivity Kekonduksian elektrik
– Cannot conduct electricity when in
solid
but is able to conduct electricity when in or aqueous form.
form molten
Tidak boleh mengkonduksi elektrik dalam keadaan pepejal tetapi boleh mengkonduksi elektrik dalam keadaan leburan atau akueus .
– In solid form, the ions are not Dalam bentuk pepejal, ion-ion tidak bergerak .
free bebas
to
move . untuk
–
Cannot
conduct electricity in all state.
Tidak boleh keadaan.
mengkonduksi elektrik dalam semua
– Covalent compound is made up of neutral molecules . Sebatian kovalen terdiri daripada
molekul
yang neutral.
– No free moving ions in molten or aqueous state. Tidak ada ion bebas bergerak dalam keadaan leburan atau akueus.
– In molten or aqueous state, the ions are free to move to be attracted to the anode or cathode. bebas
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MODULE • Chemistry Form 4
Ionic compound / Sebatian ion Solubility
Keterlarutan
– Most are soluble organic solvent*. Kebanyakannya larut dalam pelarut organik*
Covalent compound / Sebatian kovalen
in water and insoluble in
Insoluble in water but soluble in organic solvents* (example: ether, alcohol, benzene, tetrachloromethane and propanone). This is because covalent molecules and organic solvents are both held together by weak Van der Waals forces.
–
dalam air tetapi tidak larut
– This is because the polarisation of water molecule. Water molecules have partially positive end (the hydrogen end) and partially negative end (the oxygen end).
Tidak larut dalam air tetapi larut dalam pelarut organik* (contoh: eter, alkohol, benzena, tetraklorometana dan propanon). Ini kerana molekul kovalen dan pelarut organik ditarik oleh daya tarikan Van der Waals yang lemah. * Organic solvents are covalent compounds that exist as liquid at room temperature. * Pelarut organik adalah sebatian kovalen yang wujud dalam bentuk cecair pada suhu bilik.
Ini kerana air adalah molekul yang berkutub. Molekul air mempunyai bahagian bercas separa positif (bahagian hidrogen) dan bahagian bercas separa negatif (bahagian oksigen).
EXERCISE / LATIHAN
The Table below shows the proton number of elements D, E, F, G, J and L.
1
Jadual di bawah menunjukkan nombor proton bagi unsur D, E, F, G, J dan L. Element / Unsur
D
E
F
G
J
L
Proton number / Nombor proton
1
6
17
11
18
8
(a) Which element in the table are metal and non-metal / Unsur yang manakah merupakan logam dan bukan logam? (i) Metal / Logam : G (ii) Non-metals / Bukan logam : D, E, F, J, L (b) State an element that exists as monoatomic gas. Explain your answer. Nyatakan unsur yang wujud sebagai gas monoatom. Terangkan jawapan anda.
Element J, Atom J has 8 electrons in the outermost shell, the atom has achieved stable octet electron arrangement. (c) Write the formula for the ion formed from an atom of element L. Tuliskan formula ion yang terbentuk daripada atom unsur L.
L2– (d) Element E reacts with element L to form a compound / Unsur E bertindak balas dengan unsur L untuk membentuk sebatian. (i) State the type of bond present in this compound / Nyatakan jenis ikatan yang wujud dalam sebatian ini. Covalent bond (ii)
Write the formula of the compound formed / Tuliskan formula bagi sebatian yang terbentuk. EL2
(iii) Explain how a compound is formed between element E and element L based on their electron arrangement. Jelaskan dari segi susunan elektron bagaimana unsur E dan unsur L bergabung membentuk sebatian.
– E atom with electron arrangement 2.4 needs four electrons to achieve stable octet electron arrangement. – L atom with an electron arrangement 2.6 needs two electrons to achieve octet electron arrangement. – One E atom share four pairs of electrons with two L atoms to form a molecule with the formula EL2. – One E atom contributes four electrons and each of the two L atoms contributes two electrons for sharing to form double covalent bond. – One E atom forms two double covalent bond with two L atoms. – E atom and L atom achieve stable octet electron arrangement that is 2.8. (e) (i)
Draw the electron arrangement of the compound formed / Lukiskan susunan elektron bagi sebatian yang terbentuk.
m
E
L
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Chemistry Form 4 • MODULE
(ii)
State one physical property of the compound / Nyatakan satu sifat fizik sebatian tersebut. Low melting/boiling point // does not dissolve in water // dissolves in organic solvents // does not conduct electricity in aqueous solution or molten state.
(f)
When element G is burnt in L gas, G burns rapidly and brightly with a yellow flame and produces white fumes. Apabila unsur G dibakar dalam gas L, G terbakar cergas dengan nyalaan kuning terang dan menghasilkan wasap putih.
(i)
Write the equation for the reaction between element G and gas L. Tuliskan persamaan kimia bagi tindak balas antara unsur G dan gas L.
4G + L2 (ii)
2G2L
.
Explain how a compound is formed between elements G and L based on their electron arrangement. Jelaskan dari segi susunan elektron bagaimana unsur G dan L bergabung membentuk sebatian.
– The electron arrangement of G atom is 2.8.1. G atom is not stable. G atom releases one valence electron to form G+ ion and achieve stable octet electron arrangement 2.8. – The electron arrangement of L atom is 2.6. L atom is also unstable. L atom receives 2 electrons to form L2– ion and achieves a stable octet electron arrangement 2.8.8. – Therefore two G atoms release two electrons to one L atom, a strong electrostatic force is formed between G+ and L2– ions. (iii) Draw the electron arrangement of the compound formed / Lukiskan susunan elektron bagi sebatian yang terbentuk. +
+
2–
G
L
G
(g) Compare the boiling point of the compounds formed in 1(d) and 1(e). Explain your answer. Bandingkan takat didih sebatian yang terbentuk di 1(d) dan 1(e). Jelaskan jawapan anda.
– The boiling point of compound G2L is high and EL2 is low. – The boiling point of compound G2L is high because positive ions and negative ions are attracted by strong electrostatic force. Large amount of energy is needed to overcome it. – The boiling point of EL2 is low because the molecules are attracted by weak Van der Waals forces, small amount of energy is needed to overcome it. 2
The diagram below shows the electron arrangement of compound A. Compound A is formed from the reaction between element X and element Y. Rajah di bawah menunjukkan susunan elektron bagi sebatian A. Sebatian A terbentuk dari tindak balas antara unsur X dan unsur Y.
+ X
(a) (i) (ii)
– Y
Write the electron arrangement for atom of elements X and Y / Tuliskan susunan elektron bagi atom unsur X dan Y. X: 2.8.1 Y: 2.8.7 Compare the size of atoms of elements X and Y. Explain your answer. Bandingkan saiz atom unsur X dan unsur Y. Jelaskan jawapan anda.
– Atom Y is smaller than atom X. n io
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– Atom X and atom Y have the same number of shells occupied with electrons.
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MODULE • Chemistry Form 4
– The number of proton in the nucleus of atom Y is more than X. – The strength nuclei attraction to the electrons in the shells of atom Y is stronger than X. (b) How are X ion and Y ion formed from their respective atoms? Bagaimana ion X dan ion Y terbentuk daripada atom masing-masing?
X ion / Ion X : Atom X releases one electron Y ion / Ion Y : Atom Y receives one electron (c) (i) (ii)
Write the formula for compound A / Tuliskan formula sebatian A. XY Name type of bond in compound A / Namakan jenis ikatan dalam sebatian A. Ionic compound
(iii) Write the chemical equation for the reaction between element X and element Y to form compound A. Tuliskan persamaan kimia untuk tindak balas antara unsur X dan unsur Y untuk membentuk sebatian A.
2X + Y2
2XY
.
(d) Y can react with carbon to form a compound. Draw the electron arrangement for the compound formed. [Given that proton number for carbon is 6] Y bertindak balas dengan karbon untuk membentuk suatu sebatian. Lukiskan susunan elektron bagi sebatian yang terbentuk. [Diberi nombor proton karbon ialah 6]
The table below shows the nucleon number, the number of neutrons and number of electrons in particles X, Y, Z, Q, R, T and U.
3
Jadual di bawah menunjukkan nombor nukleon, bilangan neutron dan bilangan elektron bagi zarah X, Y, Z, Q, R, T dan U. Particles / Zarah
X
Y
Z
Q
R
T
U
Nucleon number / Nombor nukleon
20
24
23
16
12
27
35
Number of proton / Bilangan proton
10
12
11
8
6
13
17
Number of neutron / Bilangan neutron
10
12
12
8
6
14
18
Number of electron / Bilangan elektron
10
10
11
10
6
10
17
(a) What is meant by nucleon number / Apakah maksud nombor nukleon? The total number of proton and neutron in the nucleus of an atom. (b) Complete the number of proton of the particles in the table above. Lengkapkan bilangan proton bagi zarah dalam jadual di atas.
(c) State a particle which is / Nyatakan zarah yang merupakan (i)
an atom of a non-metal / atom bukan logam
(ii)
an atom of a metal / atom logam
Y/T
(iv) a negative ion / ion negatif
Q
(v)
T
a positive ion with charge 3+ / ion positif dengan cas 3+
X
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(iii) a positive ion / ion positif
(vi) an atom of a noble gas / atom gas adi m
X/R
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Chemistry Form 4 • MODULE
(d) Particle Y combines with particle Q to form a compound / Zarah Y bergabung dengan zarah Q untuk membentuk sebatian. (i) State the type of compound formed / Nyatakan jenis sebatian yang terbentuk. Ionic compound (ii)
Write chemical formula for the compound formed / Tuliskan formula kimia bagi sebatian yang terbentuk. YQ
(iii) Draw the electron arrangement of the compound formed / Lukiskan susunan elektron bagi sebatian yang terbentuk. 2+
2–
Q
Y
(e) Particle R combines with particle U to form a compound. Zarah R bergabung dengan zarah U untuk menghasilkan suatu sebatian.
(i)
State the type of compound formed / Nyatakan jenis sebatian yang terbentuk. Covalent compound
(ii)
(f)
Write a chemical formula for the compound formed / Tuliskan formula kimia bagi sebatian yang terbentuk. RU4
Compare the electrical conductivity of the compounds formed in 3(d) and 3(e). Explain your answer. Bandingkan kekonduksian elektrik bagi sebatian yang terbentuk di 3(d) dan di 3(e). Jelaskan jawapan anda.
– Compound in YQ cannot conduct electricity in solid state but can conduct electricity in molten or aqueous solution. Compound RU4 cannot conduct electricity in molten and aqueous states. – In solid form the ions in compound YQ are not free to move but in molten and aqueous state, the ions are free to move to be attracted to the anode and cathode. – Compound RU4 only consists of neutral molecules, there are no free moving ions in molten or aqueous state. 4
The table below shows the melting point and electrical conductivity of substances W, X, Y and Z. Jadual di bawah menunjukkan takat lebur dan kekonduksian elektrik bagi bahan W, X , Y dan Z. Substance Bahan
Electrical conductivity / Kekonduksian elektrik
Melting point (°C) Takat Lebur (°C)
V
–7
W
80
X
808
Y
1 080
Solid / Pepejal
Molten / Leburan
Cannot conduct electricity
Cannot conduct electricity
Tidak mengkonduksi elektrik
Tidak mengkonduksi elektrik
Cannot conduct electricity
Cannot conduct electricity
Tidak mengkonduksi elektrik
Tidak mengkonduksi elektrik
Cannot conduct electricity
Conduct electricity
Tidak mengkonduksi elektrik
Mengkonduksi elektrik
Conduct electricity
Conduct electricity
Mengkonduksi elektrik
Mengkonduksi elektrik
(a) Which of the substance is copper? Give reason for your answer. Antara bahan di atas, yang manakah kuprum? Beri sebab bagi jawapan anda.
Y. It can conduct electricity in solid and molten state. (b) (i)
State the type of particles in substances V and W / Nyatakan jenis zarah dalam bahan V dan W. Molecule
(ii)
Explain why substances V and W cannot conduct electricity in solid and molten state. Jelaskan mengapa bahan V dan W tidak boleh mengkonduksi elektrik dalam keadaan pepejal dan leburan.
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Substances V and W are made up of neutral molecules. No free moving ions in molten state.
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MODULE • Chemistry Form 4
(c) The boiling point of substance V is 59°C. What is the physical state of substance V at room temperature? Takat didih bahan V adalah 59°C. Apakah keadaan fizikal bahan V pada suhu bilik?
Liquid (d) Draw the arrangement of particle V at room temperature / Lukiskan susunan zarah V pada suhu bilik.
(e) Explain why the melting and boiling points of substances V and W are low? Jelaskan mengapa takat lebur dan takat didih bahan V dan W rendah?
– Van der Waals / intermolecular forces between molecules are weak. – Small amount of heat energy is required to overcome it. (f)
(i) (ii)
State the type of particle in substance X / Nyatakan jenis zarah dalam sebatian X. Ion . Explain why substance X cannot conduct electricity in solid but can conduct electricity in molten state. Jelaskan mengapa bahan X tidak boleh mengkonduksi elektrik dalam keadaan pepejal tetapi boleh mengkonduksi elektrik dalam keadaan leburan.
Ions are not freely moving // ions are in a fixed position in solid state. Ion can move freely in molten state.
Objective Questions / Soalan Objektif 1
Which substance is an ionic compound? Antara bahan berikut, yang manakah adalah sebatian ion?
A B C D 2
4
Methane, CH4 / Metana, CH4 Carbon dioxide, CO2 / Karbon dioksida, CO2 Propanol, C3H7OH / Propanol, C3H7OH Copper(II) oxide, CuO / Kuprum(II) oksida, CuO
12
Apakah susunan elektron bagi ion yang terbentuk dari atom T?
A B C D
3
Volatile / Mudah meruap Has a low melting point Mempunyai takat lebur rendah
Insoluble in water / Tidak larut dalam air Conducts electricity in the molten state Mengalirkan arus elektrik dalam keadaan leburan
The diagram below shows the electron arrangement of a compound formed between atoms X and Y.
5
Jadual di bawah menunjukkan susunan elektron atom P, Q, R dan S.
Y X
Y
Y
Which of the following statements is true about the compound? Antara pernyataan berikut, yang manakah adalah benar tentang sebatian itu?
A B C
m
Atom / Atom
Electron arrangement / Susunan elektron
P
2.4
Q
2.8.1
R
2.8.2
S
2.8.7
Which pair of atoms forms a compound by transferring of electrons? Antara pasangan berikut, yang manakah membentuk sebatian secara perpindahan elektron?
A B C D
P and S / P dan S P and R / P dan R Q and S / Q dan S Q and R / Q dan R
Sebatian itu mempunyai takat lebur yang tinggi.
The compound conducts electricity. Sebatian itu boleh mengkonduksi elektrik.
The compound is formed by sharing of electrons. Sebatian terbentuk secara perkongsian elektron.
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It is an ionic compound / Ia adalah sebatian ion. The compound has high melting point.
2.8 2.8.2 2.8.8 2.8.8.8
The table below shows the electron arrangements of atoms P, Q, R and S.
Rajah di bawah menunjukkan susunan elektron dalam sebatian yang terbentuk antara atom X and atom Y.
Y
T
What is the electron arrangement of ion formed by an atom of T?
Which of the following is a property of zinc chloride?
C D
Rajah menunjukkan simbol unsur T. 24
Antara berikut, yang manakah adalah sifat zink klorida?
A B
The diagram shows symbol of an element T.
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Chemistry Form 4 • MODULE
6
The table below shows the proton number of four elements P, Q, R and S. Jadual di bawah menunjukkan nombor proton unsur P, Q, R dan S.
9
The diagram below shows the electron arrangement for an ion of element Q. Rajah di bawah menunjukkan susunan elektron ion unsur Q.
Element / Unsur
P
Q
R
S
Proton number / Nombor proton
6
8
17
20
2–
Which of the following pairs will form a compound with high melting and boiling points?
Q
Antara pasangan berikut, yang manakah membentuk sebatian dengan takat lebur dan takat didih yang tinggi?
A B 7
C D
P and Q / P dan Q Q and S / Q dan S
P and R / P dan R Q and R / Q dan R
The table below shows the proton number of elements X and Y.
What are the number of protons and electrons in an atom of element Q? Apakah bilangan proton dan elektron dalam atom unsur Q?
Number of protons
Number of electrons
A
20
20
Jadual berikut menunjukkan nombor proton unsur X dan Y.
Element / Unsur
X
Y
Proton number / Nombor proton
6
8
Bilangan elektron
What type of bond and the chemical formula of the compound formed between atoms X and Y?
B
20
18
C
16
16
Apakah jenis ikatan dan formula kimia bagi sebatian yang terbentuk antara atom X dan Y ?
D
18
18
Type of bond
Chemical formula
A
Ion / Ion
YX2
B
Ion / Ion
XY2
Element / Unsur
P
Q
R
C
Covalent / Kovalen
XY2
Proton number / Nombor proton
10
11
12
D
Covalent / Kovalen
YX2
Jenis ikatan
8
Bilangan proton
Formula kimia
The diagram below shows the electron arrangement of ion X +. Rajah di bawah menunjukkan susunan elektron ion X +.
X
10 The table below shows the proton number of elements P, Q and R. Jadual di bawah menunjukkan nombor proton unsur P, Q dan R.
Which of the following particles contain 10 electrons? Antara berikut, yang manakah adalah zarah yang mengandungi 10 elektron?
I II III IV A B C
Which of the following is the position of element X in the Periodic Table?
D
Q P Q+ R2+ I, II and III only I, II dan III sahaja
I, II and IV only I, II dan IV sahaja
I, III and IV only I, III dan IV sahaja
II, III and IV only II, III dan IV sahaja
Antara berikut, yang manakah adalah kedudukan unsur X dalam Jadual Berkala?
Group / Kumpulan
Period / Kala
A
1
3
B
18
3
1
4
D
18
4
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MODULE • Chemistry Form 4
5
ELECTROCHEMISTRY ELEKTROKIMIA
ELECTROLYSIS / ELEKTROLISIS • CONDUCTOR AND ELECTROLYTE / KONDUKTOR DAN ELEKTROLIT – To differentiate between electrolyte and conductor with regard to electrical conductivity and any chemical changes that may occur. Membezakan elektrolit dan konduktor dari segi kebolehan mengkonduksikan elektrik dan sebarang perubahan kimia yang berlaku.
– To list examples of substances which are classified as electrolytes and conductors. Menyenaraikan contoh-contoh bahan yang dikelaskan sebagai elektrolit dan konduktor.
• ELECTROLYSIS CELL / SEL ELEKTROLISIS – To draw and label the electrolytic cell / Melukis dan melabelkan sel elektrolisis. – To identify anode and cathode in the electrolytic cell diagram / Mengenali anod dan katod dalam rajah sel elektrolisis. • IONIC THEORY / TEORI ION – To relate the existence of free moving ions in an electrolyte with the electron flow in an external circuit. Mengaitkan kewujudan ion-ion yang bebas bergerak dalam elektrolit dengan proses pengaliran elektron dalam litar luar.
– To explain the electrolysis process / Menerangkan proses elektrolisis. – To conclude that electrolysis process involve changes from electrical to chemical energy. Membuat kesimpulan proses elektrolisis sebagai perubahan tenaga elektrik kepada tenaga kimia.
• FORMATION OF FREE MOVING IONS / PEMBENTUKAN ION BEBAS BERGERAK – To differentiate molten and aqueous electrolytes / Membezakan elektrolit lebur dan akueus. – To write the ionisation equation of molten and aqueous electrolytes. Menulis persamaan pengionan untuk elektrolit lebur dan akueus.
• REACTION AT ELECTRODE / TINDAK BALAS DI ELEKTROD – To write the discharge equation at the anode, where the anion releases electron. Focus on ions that are normally selected for discharge, such as chloride, hydroxide and bromide ions. Menulis persamaan di anod yang melibatkan anion melepaskan elektron. Fokus adalah kepada ion-ion yang biasa terpilih untuk nyahcas seperti ion klorida, ion hidroksida dan ion bromida.
– To write the discharge equation at the cathode, where the cation receives electron. Focus on ions that are normally selected for discharge, such as hydrogen, copper(II) and silver ions. Menulis persamaan di katod yang melibatkan kation menerima elektron. Fokus adalah kepada ion yang biasa terpilih untuk nyahcas seperti ion hidrogen, ion kuprum(II) dan ion argentum.
• FACTORS THAT AFFECT REACTIONS AT THE ELECTRODES FAKTOR-FAKTOR YANG MEMPENGARUHI TINDAK BALAS DI ELEKTROD (i) The position of ions in the electrochemical series – for dilute solutions and inert electrodes. Kedudukan ion dalam siri elektrokimia – bagi larutan cair dan elektrod lengai
(ii) The concentration – for concentrated solutions and inert electrodes / Kepekatan – bagi larutan pekat dan elektrod lengai. (iii) The types of electrode – for diluted solutions and reactive electrodes / Jenis elektrod – bagi larutan cair dan elektrod tak lengai. • ELECTROLYSIS IN INDUSTRY / KEGUNAAN ELEKTROLISIS DALAM INDUSTRI – Electrolysis in electroplating, purifying and extracting metals / Elektrolisis dalam penyaduran, penulenan dan pengekstrakan logam.
VOLTAIC CELL / SEL KIMIA • ELECTROCHEMICAL SERIES / SIRI ELEKTROKIMIA – To define and memorise the sequence of metal including hydrogen in the Electrochemical Series. Menakrif dan menghafal siri logam termasuk hidrogen dalam Siri Elektrokimia.
• APPLICATION OF ELECTROCHEMICAL SERIES IN DISPLACEMENT OF METALS APLIKASI SIRI ELEKTROKIMIA DALAM PENYESARAN LOGAM – To predict the displacement of metal reactions based on the positions of metals in the Electrochemical Series. Meramal tindak balas penyesaran logam berdasarkan kedudukan logam dalam Siri Elektrokimia.
– To write the equation of displacement reaction and to state the observations. Menulis persamaan tindak balas penyesaran dan menyatakan pemerhatian.
– To describe the metal displacement experiment to construct the Electrochemical Series. Menghuraikan eksperimen penyesaran logam bagi membina Siri Elektrokimia.
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• APPLICATION OF ELECTROCHEMICAL SERIES IN VOLTAIC CELL APLIKASI SIRI ELEKTROKIMIA DALAM SEL KIMIA – To determine the negative and positive terminals of a voltaic cell / Menentukan terminal negatif dan positif suatu sel kimia. – To predict the voltage of voltaic cell / Meramal voltan sel kimia. – To determine the direction of electron flow / Menentukan arah pengaliran elektron.
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Chemistry Form 4 • MODULE
ELECTROLYSIS / ELEKTROLISIS 1
Three types of substances that can be classified based on electrical conductivity. Bahan boleh dibahagikan kepada tiga jenis berdasarkan kekonduksian elektrik. Type of substance
Definition
Conductor Konduktor
Example
Definisi
Jenis bahan
Contoh
Element that can conduct electricity Copper, lead, tin, silver and carbon Kuprum, plumbum, stanum, argentum dan karbon at solid or molten state without any chemical changes , normally metals and carbon. Unsur yang boleh mengkonduksi arus elektrik dalam keadaan pepejal atau leburan tanpa perubahan kimia , biasanya logam dan karbon.
Electrolyte Elektrolit
Compounds that can conduct electricity in *molten state or *aqueous solution and undergo chemical changes . Sebatian yang boleh mengkonduksikan arus elektrik dalam keadaan *lebur atau *akueus serta mengalami perubahan kimia . * Molten state: a solid that is heated until it melts. * Lebur: pepejal yang dipanaskan sehingga cair. * Aqueous solution: a solid that is dissolved in water. * Akueus: pepejal yang larut di dalam air.
– Aqueous solution of ionic compound such as copper(II) sulphate solution and sodium chloride solution. Larutan akueus bagi sebatian ion contohnya larutan kuprum(II) sulfat dan larutan natrium klorida.
– Aqueous solution of *acid or alkali such as hydrochloric acid (HCl) and ammonia solution (NH3). Larutan akueus *asid atau alkali contohnya asid hidroklorik (HCl) dan larutan ammonia (NH3 ).
– Molten ionic compounds such as molten lead(II) bromide, molten sodium chloride and molten aluminium oxide. ion contohnya leburan plumbum(II) Leburan sebatian bromida, leburan natrium klorida dan leburan aluminium oksida.
* HCl and NH3 are covalent compounds, exist in form of molecule without water but ionised in water. (Explanation is in the next topic i.e acid and base) * HCl dan NH3 adalah sebatian kovalen, yang terdiri daripada molekul dalam keadaan tanpa air tetapi ianya terion dalam air (akan dijelaskan dalam tajuk seterusnya iaitu dalam asid dan bes)
2
Non- electrolyte
Compounds that cannot conduct electricity Molten covalent compound such as naphthalene, molten in molten and aqueous solution. sulphur and liquid bromine.
Bukan elektrolit
Sebatian kimia yang tidak boleh mengkonduksikan elektrik dalam keadaan lebur dan akueus.
process
Electrolysis is a current passes
3
contohnya naftalena, sulfur lebur dan cecair
whereby an electrolyte is decomposed to its constituent elements when electric penguraian elektrolit kepada unsur juzuknya apabila
Energy change in electrolysis process is electric energy to
chemical energy
Perubahan tenaga dalam proses elekrolisis adalah dari tenaga elektrik kepada 4
kovalen
through it. proses
Elektrolisis adalah
Leburan sebatian bromin.
arus elektrik
dialirkan melaluinya.
.
tenaga kimia
.
Conductor which is dipped into electrolyte which carries electric current in and out of electrolyte is called an
electrode
.
Electrode
is normally made up of
inert
substance such as carbon.
Konduktor yang dicelup dalam elektrolit yang mengalirkan arus elektrik ke dalam dan keluar daripada elektrolit dipanggil Elektrod lengai biasanya terdiri daripada bahan seperti karbon. 5
An electrolytic cell is a set-up of apparatus that contains two electrodes which are dipped in an battery and produce a chemical reaction when connected to a (source of electricity). elektrolit
.
electrolyte
dan menghasilkan
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elektrod yang dicelup ke dalam Sel elektrolisis adalah susunan radas yang terdiri daripada dua bateri . (sumber arus elektrik). tindak balas kimia apabila disambungkan kepada
elektrod
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MODULE • Chemistry Form 4
Example of electrolytic cell / Contoh sel elektrolisis:
(i)
(ii)
(iii) Electrolyte
A
Electrodes Elektrod
Elektrolit
Electrode
Electrode
Electrolyte
Elektrod
Elektrod
Elektrolit
Electrodes
Electrolyte Elektrolit
Heat
Panaskan
Electrolysis of aqueous electrolyte (No gas released)
Electrolysis of molten electrolyte Elektrolisis elektrolit lebur
Elektrod
A
Electrolysis of aqueous electrolyte (Gas is released)
Elektrolisis elektrolit dalam bentuk akueus (Tiada gas dibebaskan)
Elektrolisis elektrolit dalam bentuk larutan (Gas dibebaskan)
Electric current from the battery flows into the electrolyte through the electrode. There are two types of electrode in the electrolytic cell:
6
Arus elektrik dari bateri mengalir ke dalam elektrolit melalui elektrod. Terdapat dua jenis elektrod dalam sel elektrolisis:
(a) Anode: An electrode that is connected to the Anod: Elektrod yang disambung kepada
positive terminal
terminal positif
bateri dalam sel elektrolisis.
negative terminal
(b) Cathode: An electrode that is connected to the Katod: Elektrod yang disambung kepada
of the battery.
terminal negatif
of the battery.
bateri dalam sel elektrolisis.
An electrolyte consists of free moving ions because it is in a molten or aqueous state. Each ion moves to the opposite charge electrode. There are two types of ions in electrolyte:
7
Dalam keadaan lebur atau akueus, elektrolit terdiri daripada ion-ion yang bergerak bebas. Setiap ion bergerak kepada elektrod yang bertentangan cas. Terdapat dua jenis ion dalam elektrolit:
(a) Anions: Negative ions which are attracted and move to the positively charged electrode, Anion: Ion
(b) Cations: Kation: Ion
negatif
Positive
akan tertarik dan bergerak ke arah elektrod
anod
yang bercas
positif
ions which are attracted and move to the negatively charged electrode,
positif
akan tertarik dan bergerak ke arah elektrod
katod
yang bercas
negatif
anode
.
cathode
.
. .
Electrolysis occurs at the electrode when electric current flows in the electrolytic cell. The stages in electrolysis process are:
8
Proses elektrolisis berlaku di elektrod apabila arus elektrik mengalir melalui sel elektrolisis. Peringkat dalam proses elektrolisis adalah seperti berikut:
(a) Anions (negative ions) are attracted and move to the
anode
of anode and become neutral atoms or molecule. The anions are Anion (ion negatif) akan tertarik dan bergerak ke arah menjadi atom/molekul. Anion dinyahcaskan pada anod.
(b) Electrons flow from the Elektron mengalir dari
anode anod
to the ke
katod
anod
cathode
. The anions release electrons to the surface discharged at the anode.
. Anion melepaskan elektron pada permukaan anod dan
through the connecting wire in the external circuit .
melalui wayar penyambung dalam
(c) Cations (positive ions) are attracted and move to the
litar luar
.
cathode
. The cations receive electrons at the surface of cathode and become neutral atoms or molecules. The cations are discharged at the cathode. katod Kation (ion positif) akan tertarik dan bergerak ke arah menjadi atom/molekul. Kation dinyahcaskan pada katod.
. Kation menerima elektron pada permukaan katod dan
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– Electrons flow through the external circuit / Elektron mengalir melalui litar luar. – Chemical changes occur at the anode and cathode / Perubahan kimia berlaku di anod dan katod.
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Chemistry Form 4 • MODULE
FORMATION OF FREE MOVING IONS IN THE ELECTROLYTE PEMBENTUKAN ION BERGERAK BEBAS DALAM ELEKTROLIT 1
Ionisation equation is an equation to determine the ions present in molten or aqueous electrolyte. Persamaan pengionan adalah persamaan yang menunjukkan ion yang hadir dalam elektrolit sama ada dalam keadaan leburan atau akueus.
(a) Example of ionisation of molten electrolyte (a compound that is heated until it melts) Contoh pengionan elektrolit dalam keadaan leburan (sebatian yang dipanaskan sehingga lebur)
(i)
Molten sodium chloride / Natrium klorida lebur:
NaCl (s)
Na+(l) + Cl–(l)
(ii) Molten lead (II) bromide / Plumbum (II) bromida lebur: PbBr2 (s)
Pb2+(l) + 2Br –(l)
(iii) Molten sodium oxide / Natrium oksida lebur:
Na2O (s)
2Na+(l) + O2–(l)
(iv) Molten aluminium oxide / Aluminium oksida lebur:
Al2O3 (s)
2Al3+(l) + 3O2–(l)
(b) Example of the ionisation on an aqueous electrolyte (a compound that is dissolved in water): Contoh pengionan elektrolit dalam keadaan akueus (sebatian yang dilarutkan dalam air): Na+(aq) + Cl+(aq) (i) Sodium chloride solution / Larutan natrium klorida: NaCl(aq / ak )
2
H+(aq) + OH–(aq)
(ii) Copper(II) sulphate solution / Larutan kuprum(II) sulfat: CuSO4(aq / ak )
Cu2+ + SO42–
H2O
H2O
(iii) Sulphuric acid / Asid sulfurik:
H2SO4(aq / ak )
H2O
H+ + OH–
2H+ + SO42– H+ + OH–
Ionisation of molten electrolyte produces cation and anion of the compound only. However the ionisation of an aqueous electrolyte produces cation and anion from the ionisation of the compound and water. Pengionan elektrolit dalam keadaan lebur hanya menghasilkan kation dan anion dari sebatian itu sahaja. Pengionan elektrolit dalam keadaan akueus menghasilkan kation dan anion daripada sebatian dan air.
Example / Contoh: molten
(i) Ionisation of Pengionan
leburan
sodium chloride produces Na+ and Cl– only. natrium klorida menghasilkan Na+ dan Cl– sahaja.
aqueous
(ii) Ionisation of
sodium chloride produces Na+, H+, Cl– and OH–.
akueus
Pengionan larutan
natrium klorida menghasilkan Na+, H+, Cl– dan OH–.
REACTIONS AT THE ELECTRODES / TINDAK BALAS DI ELEKTROD 1
The process of cation gaining electron at the cathode or anion losing electrons at the anode is called discharged : nyahcas
Proses apabila kation menerima elektron di katod atau anion melepaskan elektron di anod dipanggil
(a) A cation is Kation
discharged
dinyahcaskan dinyahcaskan
(c) When ions are Apabila ion 2
apabila
discharged
(b) An anion is Anion
when it
discharged
dinyahcaskan
menerima
when it
apabila
receives
electrons at the cathode.
elektron di katod.
releases
melepaskan
electrons at the anode.
elektron di anod.
, they become neutral
atom
atom
atau
, ianya akan menjadi
:
or molecule . molekul
The ionic equation that occurs at the anode and cathode to produce neutral ‘half equation’. atom
atau
atom
or molecule is called
molekul
neutral dipanggil ‘persamaan
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Persamaan ion yang berlaku di anod dan di katod untuk menghasilkan setengah’.
yang neutral.
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MODULE • Chemistry Form 4
Common half equation at the anode (anion/metal atom releases electrons):
3
Persamaan setengah yang biasa di anod (anion/atom logam melepaskan elektron): Half equation
Explanation
Persamaan setengah
4OH–
Penerangan
2H2O + O2 + 4e
2Cl–
Cl2 + 2e
2Br–
Cu
Cu2+ + 2e
Ag
Ag+ + e
Empat ion hidroksida
melepaskan
Two chloride ions
release
melepaskan
Dua ion klorida
Br2 + 2e
release
Four hydroxide ions molecule .
Two bromide ions Dua ion bromida
Copper atom
releases
releases
Atom argentum
melepaskan
oksigen.
.
klorin.
molekul
dua elektron membentuk satu
molecule
.
bromin.
copper(II) ion
ion kuprum(II)
dua elektron membentuk
Silver atom
molekul
two electrons to form one bromine
two electrons to form
melepaskan
molecule
two electrons to form one chlorine
release
molekul
empat elektron membentuk dua molekul air dan satu
dua elektron membentuk satu
melepaskan
Atom kuprum
four electrons to form two water molecules and one oxygen
.
.
one electron to form
silver ion
satu elektron membentuk
ion argentum .
.
Common half equation at the cathode (cation receives electrons):
4
Persamaan setengah yang biasa di katod (kation menerima elektron): Half equation
Explanation
Persamaan setengah
2H+ + 2e
Ag+ + e
Cu2+ + 2e
H2
Ag
Cu
Penerangan
Two hydrogen ions Dua ion hidrogen
Silver ion
receive
Ion argentum
menerima
Copper(II) ion Ion kuprum(II)
receive
menerima
molekul
dua elektron membentuk satu
receives
satu elektron membentuk satu
atom
two electrons to form one copper dua elektron membentuk satu
atom
.
hidrogen.
atom
one electron to form one silver
menerima
molecule
two electrons to form one hydrogen
.
argentum.
atom
.
kuprum.
Write the equation of discharge of ion
5
Tuliskan persamaan setengah untuk nyahcas ion yang berikut:
(i) Lead(II) ion to lead atom
:
Ag++ e Ag
:
2I– I2 + 2e
Ion argentum kepada atom argentum
(iii) Iodide ion to iodine molecule
Pb2+ + 2e Pb
Ion plumbum(II) kepada atom plumbum
(ii) Silver ion to silver atom /
:
Ion iodida kepada molekul iodin
EXERCISE / LATIHAN
Using lead(II) bromide as an example, explain the electrolysis of molten lead(II) bromide. In your explanation, draw a labeled diagram for the set up of apparatus and show the movement of particles by using arrows that occur in lead(II) bromide and the direction of electron flow in the external circuit.
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Chemistry Form 4 • MODULE
Set-up of apparatus / Rajah susunan radas:
Carbon electrodes
Lead(II) bromide
Heat
Explanation / Penerangan:
– The ions present are lead(II) ions/ Pb2+ and bromide ions/ Br –. – Bromide ion/ Br – move to the anode. – Bromide ion/ Br – releases one electron to form bromine atom at the anode. – Two bromine atoms combine to form bromine molecule. – 2Br – Br2 + 2e – Lead(II) ions/Pb2+ move to the cathode. – Lead(II) ions/Pb2+ receive two electrons to form lead atom at the cathode. – Pb2+ + 2e Pb
FACTOR THAT AFFECT THE ELECTROLYSIS OF AN AQUEOUS SOLUTION FAKTOR YANG MEMPENGARUHI ELEKTROLISIS LARUTAN AKUEUS
When more than one type of ion are attracted towards the electrodes during electrolysis, only one type of ion is selected to be discharged at each electrode. Selective discharge only occurs in aqueous solution because it usually has more than one type of ion attracted to the anode or cathode.
1
Apabila lebih dari satu jenis ion bergerak ke elektrod semasa elektrolisis, hanya satu jenis ion sahaja yang akan dipilih untuk dinyahcas pada setiap elektrod. Pemilihan nyahcas ion hanya berlaku di dalam larutan akueus sahaja kerana ia biasanya mempunyai lebih dari satu jenis ion yang tertarik ke anod atau katod.
The selection of ion for discharge depends on three factors / Pemilihan ion untuk nyahcas bergantung pada tiga faktor: (a) The position of ions in the electrochemical series (normally in dilute solution and inert electrode).
2
Kedudukan ion dalam siri elektrokimia (biasanya dalam larutan cair dan elektrod lengai).
(b) The concentration of electrolyte (normally in concentrated solution and inert electrode). Kepekatan elektrolit (biasanya dalam larutan pekat dan elektrod lengai).
(c) The types of electrode (when reactive metal electrode is used). Jenis elektrod (apabila elektrod logam reaktif digunakan). The position of ions in the Electrochemical Series / Kedudukan ion dalam Siri Elektrokimia:
3
(a) When electrolysis is conducted on dilute solution and inert electrodes, the lower position of cation in the Electrochemical Series, or anions in the lower position of the anion discharge series will be selected to be discharged. Apabila elektrolisis dijalankan ke atas larutan cair dan elektrod lengai, kation yang lebih rendah kedudukan dalam Siri Elektrokimia atau anion yang lebih rendah kedudukan dalam siri discas anion akan dinyahcas.
Cation: K+, Na+, Ca2+, Mg2+, Al3+, Zn2+, Fe2+, Sn2+, Pb2+, H+, Cu2+, Ag+, and Au+ Kation: K+, Na+, Ca2+, Mg2+, Al3+, Zn2+, Fe2+, Sn2+, Pb2+, H+, Cu2+, Ag+, dan Au+
Increasing ease of discharge of ion from left to right
Ion semakin mudah dinyahcas dari kiri ke kanan – 2– – Anion: F , SO4 , NO3 , Cl–, Br –, I–, and OH–
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Anion: F–, SO42–, NO3–, Cl–, Br –, I–, dan OH–
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MODULE • Chemistry Form 4
(b) Choose the ion to be discharged from the following pairs of ions. State the electrode where it occurs and write the half equation for the discharge of ion: Pilih ion yang akan dinyahcas dari pasangan ion berikut, nyatakan di elektrod mana ia berlaku dan tulis persamaan setengah untuk nyahcas ion:
(i)
Ion hidroksida & ion sulfat
(ii) Hydroxide & nitrate ions Ion hidroksida & ion nitrat
(v) Hydrogen & silver ions Ion hidrogen & ion argentum
4OH
–
: Half equation: : Persamaan setengah:
4OH
–
Cu + 2e Cu Cu2+ + 2e
: Persamaan setengah:
Ag + e Ag
: Persamaan setengah:
Ag + e +
katod
di
Ag
di
katod
.
.
cathode
at the
.
.
cathode
at the
H2
+
: Half equation:
katod
di
.
.
cathode
at the
2H + 2e H2
: Persamaan setengah:
anod
di
.
.
anode
at the
Cu
+
2H+ + 2e
anod
di
2H2O + O2 + 4e
2+
anode
at the
2H2O + O2 + 4e
4OH– 2H2O + O2 + 4e
(iv) Hydrogen & potassium ions : Half equation: Ion hidrogen & ion kalium
: Persamaan setengah:
(iii) Hydrogen & copper(II) ions : Half equation: Ion hidrogen & ion kuprum(II)
4OH– 2H2O + O2 + 4e
Hydroxide & sulphate ions : Half equation:
.
.
(c) Complete the following table for the electrolysis of 0.1 mol dm–3 sodium nitrate solution using carbon electrode. Lengkapkan jadual berikut bagi elektrolisis larutan natrium nitrat 0.1 mol dm–3 menggunakan elektrod karbon. Set-up of apparatus
Susunan radas
Carbon electrodes
Sodium nitrate
NaNO3 H2O
Equation of electrolyte ionisation Persamaan pengionan elektrolit
Electrode / Elektrod
Na+ + NO3– H+ + OH–
Anode / Anod
Ions that are attracted to the anode and cathode NO3–, OH–
Cathode / Katod Na+, H+
Ion yang ditarik ke anod dan katod
Half equation Persamaan setengah
Name of the products
2H+ + 2e
H2
Hydrogen
Pemerhatian
Gas bubbles are released.
Gas bubbles are released.
Confirmatory test (method and observations)
– Insert a glowing wooden splinter into – When a lighted wooden splinter is test tube. placed near the mouth of the test tube. – Glowing wooden splinter is lighted up. – A ‘pop’ sound is produced.
Observations
Ujian pengesahan (kaedah dan pemerhatian)
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2H2O + O2 + 4e
Oxygen
Nama hasil
m
4OH–
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Chemistry Form 4 • MODULE
(d) Complete the following table for the electrolysis of 0.1 mol dm–3 sulphuric acid using carbon electrodes. Lengkapkan jadual berikut bagi elektrolisis asid sulfurik 0.1 mol dm–3 menggunakan elektrod karbon. Set-up of apparatus Susunan radas
Carbon electrodes
Sulphuric acid
H2SO4
Equation of electrolyte ionisation
H2O
Persamaan pengionan elektrolit
2H+ + SO42– H+ + OH–
Electrode / Elektrod
Anode / Anod
Cathode / Katod
Ions that are attracted to the anode and cathode
SO42–, OH–
H+
Ion yang ditarik ke anod dan katod
Half equation
4OH–
Persamaan setengah
Name of the products Nama hasil
Observations Pemerhatian
Confirmatory test (method and observations) Ujian pengesahan (kaedah dan pemerhatian)
2H2O + O2 + 4e
2H+ + 2e
H2
Oxygen
Hydrogen
Gas bubbles are released.
Gas bubbles are released.
– Insert a glowing wooden splinter into – When a lighted wooden splinter is test tube. placed near the mouth of the test tube. – Glowing wooden splinter is lighted up. – A ‘pop’ sound is produced.
(e) Complete the following table for the electrolysis of 0.1 mol dm–3 copper(II) sulphate solution using carbon electrodes. Lengkapkan jadual berikut bagi elektrolisis larutan kuprum(II) sulfat 0.1 mol dm–3 menggunakan elektrod karbon. Set-up of apparatus Susunan radas
Carbon electrodes
Copper(II) sulphate
H2SO4
Equation of electrolyte ionisation
H2O
Persamaan pengionan elektrolit
2H+ + SO42– H+ + OH–
Anode / Anod
Electrode / Elektrod
Cathode / Katod
Ions that are attracted to the anode and SO42–, OH– cathode
Cu2+, H+
Half equation
Cu2+ + 2e
Ion yang ditarik ke anod dan katod Persamaan setengah
Name of the products Nama hasil
Observations Pemerhatian
Confirmatory test (method and observations)
4OH–
2H2O + O2 + 4e
Cu
Oxygen
Copper
Gas bubbles are released.
Brown solid deposited
– Insert a glowing wooden splinter into test tube. – Glowing wooden splinter is lighted up.
–
Ujian pengesahan (kaedah dan pemerhatian)
4
Concentration of electrolyte / Kepekatan elektrolit: (a) When electrolysis is carried out using inert electrodes and concentrated solutions, ions that are more concentrated will be discharged but this is only true for halide ions, which are Cl–, Br – and I–. Apabila elektrolisis dijalankan menggunakan elektrod lengai dan larutan pekat, ion yang lebih pekat akan dinyahcas tetapi ia benar untuk ion-ion halida sahaja iaitu Cl–, Br– dan I–. n io
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Nyatakan ion yang terpilih untuk dinyahcaskan di anod dan di katod bagi larutan pekat di bawah.
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(b) State the selected ions to be discharged at the anode and cathode for the following concentrated solutions.
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MODULE • Chemistry Form 4
(i)
Concentrated hydrochloric acid solution, using carbon electrodes Larutan asid hidroklorik pekat menggunakan elektrod karbon
Cl– Anode / Anod: Cathode / Katod: (ii) Concentrated potassium iodide solution, using carbon electrodes
l– Anode / Anod: Cathode / Katod: (iii) Concentrated sodium chloride solution, using carbon electrodes
H+
Larutan kalium iodida pekat menggunakan elektrod karbon
K+
Larutan natrium klorida pekat menggunakan elektrod karbon
Anode / Anod:
Cl–
H+
Cathode / Katod:
(c) Complete the following table for the electrolysis of 0.001 mol dm–3 hydrochloric acid and 2.0 mol dm–3 hydrochloric acid, using carbon electrodes. Lengkapkan jadual berikut bagi elektrolisis asid hidroklorik 0.001 mol dm–3 dan asid hidroklorik 2.0 mol dm–3 menggunakan elektrod karbon. Set-up of apparatus Susunan radas
Carbon electrodes
Hydrochloric acid
HCl
Equation of electrolyte ionisation
H2O
Persamaan pengionan elektrolit
Half equation at the cathode Persamaan setengah di katod
Observation at cathode Pemerhatian di katod
Confirmatory test at cathode (method and observations) Ujian pengesahan (kaedah dan pemerhatian)
Name the products at the cathode Nama hasil di katod
Ions that are attracted to the anode Ion bergerak ke anod
Half equation at the anode Persamaan setengah di anod
H+
H+
2H+ + 2e
H2
Gas bubbles are released.
2H+ + 2e
H2
Gas bubbles are released.
– Insert a burning wooden splinter into – Insert a burning wooden splinter into the test tube. the test tube. – A ‘Pop’ sound is produced. – A ‘pop’ sound is produced. Hydrogen gas
Hydrogen gas
Cl– , OH–
Cl– , OH–
4OH–
2H2O + O2 + 4e
2Cl–
Cl2 + 2e
Gas bubbles are released.
Confirmatory test at anode (method and observations)
– Insert a glowing wooden splinter into – A damp blue litmus paper placed near the test tube. the mouth of the test tube. – Glowing wooden splinter is lighted up. – The gas changed the damp blue litmus paper to red and then bleached it.
Name the product at the anode Nama hasil di anod
The concentration of hydrochloric acid after a while and explanation Kepekatan elektrolit selepas beberapa ketika dan terangkan
Oxygen gas
Greenish yellow gas is released.
Chlorine gas
Concentration of hydrochloric acid Concentration of hydrochloric acid increases . Hydrogen gas is released at decreases . Hydrogen gas released at the cathode and oxygen gas is released the cathode and chlorine gas released at at the anode. Water decomposed to the anode. Concentration of chloride oxygen gas and hydrogen gas. ions decreases. bertambah . Kepekatan asid hidroklorik Gas hidrogen dibebaskan di katod dan gas oksigen dibebaskan di anod. Air terurai kepada gas oksigen dan gas hidrogen .
berkurang Kepekatan asid hidroklorik Gas hidrogen dibebaskan di katod dan gas klorin dibebaskan di anod. Kepekatan ion klorida berkurang.
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HCl 2.0 mol dm–3
Observations at anode / Pemerhatian
Ujian pengesahan (kaedah dan pemerhatian)
m
2.0 mol dm-3 of HCl
HCl 0.001 mol dm–3
Elektrolit
Ion bergerak ke katod
H+ + OH–
0.001 mol dm-3 of HCl
Electrolyte Ions that are attracted to the cathode
H+ + Cl–
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Chemistry Form 4 • MODULE
(d) Complete the following table for the electrolysis of 2.0 mol dm–3 sodium iodide solution using carbon electrodes. Lengkapkan jadual berikut bagi elektrolisis larutan natrium iodida 2.0 mol dm–3 menggunakan elektrod karbon. Set-up of apparatus Susunan radas
Carbon electrodes
Sodium iodide
NaI H2O
Equation of electrolyte ionisation Persamaan pengionan elektrolit
Na+ + I– H+ + OH–
Electrode / Elektrod
Anode / Anod
Cathode / Katod
Ions that are attracted to the anode and cathode
I–, OH–
Na+, H+
Ion yang ditarik ke anod dan katod
Half equation
2I–
Persamaan setengah
Name of the products Nama hasil
Observations Pemerhatian
Confirmatory test (method and observations)
2H+ + 2e
H2
Iodine
Hydrogen
Brown solution is formed.
Gas bubbles are released.
– A few drops of starch solution added. – Starch solution turns to dark blue.
– When a lighted wooden splinter is placed near the mouth of the test tube. – A ‘pop’ sound is produced.
Ujian pengesahan (kaedah dan pemerhatian)
5
I2 + 2e
Types of electrode Jenis elektrod: (a) There are two types of electrode Terdapat dua jenis elektrod: (i) Inert electrode – An electrode that acts as a conductor only and does not undergo any chemical changes.
Normally they are made of carbon or platinum.
Elektrod lengai – Elektrod yang bertindak sebagai pengalir arus sahaja dan tidak mengalami perubahan kimia. Biasanya diperbuat daripada karbon atau platinum. (ii) Reactive electrode – An electrode that not only acts as a conductor but also undergoes chemical changes. During the electrolysis, the metal atom at the anode releases electron to form metal ion, metal anode becomes thinner while the less electropositive cation will be selected at the cathode which consist of metal
electrodes such as copper, silver and nickel.
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Elektrod reaktif – Elektrod yang bertindak bukan sahaja sebagai pengalir arus tetapi juga mengalami perubahan kimia. Semasa proses elektrolisis berlaku, atom logam pada anod melepaskan elektron menjadi ion logam, anod logam menjadi nipis manakala ion yang kurang elektropositif akan menyahcas di katod yang terdiri daripada logam seperti kuprum, argentum dan nikel.
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MODULE • Chemistry Form 4
(b) Complete the following table for the electrolysis of 1 mol dm–3 copper(II) sulphate solution with carbon electrode and copper electrode. Lengkapkan jadual berikut bagi elektrolisis larutan kuprum(II) sulfat 1 mol dm–3 menggunakan elektrod karbon dan elektrod kuprum. Set-up of apparatus Susunan radas
Copper(II) sulphate
Copper electrodes
Carbon electrodes
Copper(II) sulphate
CuSO4 (aq / ak ) Cu2+ + SO42– H2O H+ + OH–
Equation of electrolyte ionisation Persamaan pengionan elektrolit
Type of electrode
Carbon electrode
Jenis elektrod
The ions that move to the cathode Ion bergerak ke katod
Half equation at the cathode Persamaan setengah di katod
Name the product at the cathode Nama hasil di katod
Observation at cathode Pemerhatian di katod
The ions that move to the anode Ion bergerak ke anod
Half equation at the anode Persamaan setengah di anod
Name the product at anode Nama hasil di anod
Observations at the anode Pemerhatian di anod
Confirmatory test (method and observations) Ujian pengesahan (kaedah dan pemerhatian )
The concentration of copper(II) solution after a while and explanation
m
Cu2+, H+
Elektrod kuprum
Cu2+, H+
Cu2+ + 2e
Cu
Cu2+ + 2e
Cu
Copper
Copper
Brown solid deposited
Brown solid deposited
SO42–, OH–
SO42–, OH–
4OH–
Cu
2H2O + O2 + 4e
Cu2+ + 2e
Oxygen gas
Copper(II) ion
– Gas bubbles are released. – Intensity of blue colour decreases.
– Copper electrode becomes thinner. – Intensity of blue colour remains unchanged.
– Insert a glowing wooden splinter into the test tube. – Glowing wooden splinter is lighted up.
– Concentration of copper(II) sulphate solution decreases. – Copper(II) ions discharge as copper atoms and deposited the cathode.
–
– Concentration of copper(II) sulphate solution remains unchanged. – The number of copper atoms form copper(II) ions at the anode is equal to the number of copper(II) ions form copper atoms at the cathode.
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Kepekatan elektrolit selepas beberapa ketika dan terangkan
Copper electrode
Elektrod karbon
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Chemistry Form 4 • MODULE
EXERCISE / LATIHAN 1
Complete the table below / Lengkapkan jadual di bawah: Electrolyte Elektrolit
Electrode Factor that affects Elektrod electrolysis
Ions present Ion yang hadir
Faktor yang mempengaruhi elektrolisis
Dilute sulphuric acid
Carbon
H+, SO42–, OH–
Concentration of electrolyte
H+, Cl–, OH–
Karbon
Position of ion in the electrochemical series
Ag+, NO3–, H+, OH–
Silver
Type of electrode
Asid sulfurik cair
Concentrated hydrochloric acid
Persamaan setengah di anod dan pemerhatian
Position of ion in the electrochemical series
Karbon
Carbon Karbon
Carbon
Larutan argentum nitrat
Silver nitrate solution
4OH–
2H2O + O2 + 4e
Half equation at the cathode and observation Persamaan setengah di katod dan pemerhatian
2H+ + 2e
H2
Gas bubbles are released.
Gas bubbles are released.
2Cl–
2H+ + 2e
Cl2 + 2e
H2
Greenish yellow gas is released.
Gas bubbles are released.
4OH–
Gas bubbles are released.
Ag+ + e Ag Grey shiny solid deposited.
Ag+, NO3–, H+, OH–
Ag Ag+ + e Anode becomes thinner.
Ag+ + e Ag Grey shiny solid deposited.
Position of ion in the electrochemical series
K+, I–, H+, OH–
4OH–
2H+ + 2e
Concentration of electrolyte
K+, I–, H+, OH–
Position of ion in the electrochemical series
K+, SO42–, H+, OH–
Asid hidroklorik pekat
Silver nitrate solution
Half equation at the anode and observation
Argentum
2H2O + O2 + 4e
Larutan argentum nitrat
Carbon Dilute Karbon potassium iodide solution
2H2O + O2 + 4e
H2
Gas bubbles are released.
Gas bubbles are released.
2I–
2H+ + 2e
Larutan kalium iodida cair
Carbon Concentrated Karbon potassium iodide solution
I2 + 2e
H2
Brown solution formed.
Gas bubbles are released.
4OH–
2H+ + 2e
Larutan kalium iodida pekat
Dilute potassium sulphate solution
Carbon Karbon
2H2O + O2 +4e
Gas bubbles are released.
H2
Gas bubbles are released.
Larutan kalium sulfat cair
2
Electrolysis is carried out on a dilute potassium chloride solution using carbon electrodes. Explain how this electrolysis occurs. Use a labelled diagram to explain your answer. Proses elektrolisis dijalankan ke atas larutan kalium klorida cair menggunakan elektrod karbon. Jelaskan bagaimana proses elektrolisis ini berlaku. Gunakan gambar rajah berlabel untuk menerangkan jawapan anda. Set-up of apparatus / Susunan radas:
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Carbon electrode
Dilute potassium chloride solution Carbon electrode
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MODULE • Chemistry Form 4
Explanation / Penerangan:
K+, H+, Cl–
– Potassium chloride solution consist of
K , H , Cl +
Larutan kalium klorida mengandungi ion
Cl–
–
ion and Cl –
Ion
OH–
– –
Ion OH
OH
dan
dalam siri elektrokimia.
oxygen
2H2O + O2 + 4e
is lower than
K+ ion
water
and oksigen
dipilih untuk dinyahcaskan dengan melepaskan elektron membentuk molekul
– Half equation / Persamaan setengah: K+ ion and H+ ion move to the cathode / –
–
yang bergerak bebas.
is selectively discharged by releasing electrons to form 4OH–
–
ions that move freely.
–
ion in the electrochemical series. Cl –
terletak di bawah ion
–
H+ ion
OH–
and
bergerak ke anod.
Cl–
ion is lower than
OH– ion
–
ions move to the anode.
OH –
dan ion
OH –
Ion
OH–
+
air
dan
.
.
Ion K +
ion H +
dan
bergerak ke katod.
in the electrochemical series.
Ion H +
terletak di bawah
H+ ion
is selectively discharged by receiving electrons to form hydrogen molecules.
Ion H
dipilih untuk dinyahcaskan dengan menerima elektron membentuk molekul
+
molecule.
ion K +
dalam siri elektrokimia
2H + + 2e
– Half equation / Persamaan setengah:
H2
hidrogen
.
.
Describe an experiment to determine the product of electrolysis copper(II) sulphate solution with carbon electrode.
3
Your answer should include the observation, confirmatory test for the product at the anode and half equation at the electrode. Huraikan satu eksperimen untuk menentukan hasil elektrolisis larutan kuprum(II) sulfat menggunakan elektrod karbon. Dalam jawapan anda perlu disertakan pemerhatian, ujian pengesahan untuk hasil yang terbentuk di anod dan persamaan setengah bagi tindak balas yang berlaku di elektrod. Answer / Jawapan:
Apparatus / Radas : Battery / power supply, carbon electrodes, wire, electrolytic cell, test tube, Ammeter [from a
labelled diagram]
Material / Bahan
–3 : 1 mol dm copper(II) sulphate solution
Carbon electrodes
Copper(II) sulphate solution
Procedure / Langkah: –3 (a) Pour 1 mol dm copper(II) sulphate
Masukkan
larutan
kuprum(II) sulfat
solution 1 mol dm–3
in the electrolytic cell until it is ke dalam sel elektrolitik sehingga
(b) The apparatus is set up as shown in the diagram. Fill the anode invert the test tube on the . Radas disusunkan seperti dalam gambar rajah. Isi anod . uji itu pada
tabung uji
test tube dengan
half full
with copper(II) sulphate
larutan
.
separuh penuh
.
solution
and
kuprum(II) sulfat dan terbalikkan tabung
(c) Turn on the switch / Hidupkan suis. (d) Collect the gas produced at the anode (e) Gas produced at the
m
anod
anod / Kumpulkan gas yang terhasil di glowing wooden splinter is tested with a . diuji dengan
kayu uji berbara
.
.
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Chemistry Form 4 • MODULE
Observation and half equation / Pemerhatian dan persamaan setengah: Electrodes
Observation
Elektrod
4
Confirmatory test
Pemerhatian
Half equation
Ujian pengesahan
Cathode
Brown solid deposited
Anode
Gas bubbles are released
Persamaan setengah
Cu2+ + 2e Cu
–
– Insert the glowing wooden splinter into the test tube. – The glowing wooden splinter is lighted up.
4OH– 2H2O + O2 + 4e
Copper(II) sulphate solution is electrolysed using copper electrodes. Larutan kuprum(II) sulfat dielektrolisis dengan menggunakan elektrod kuprum.
(a) Write the formula of all the anions present in the solution / Tuliskan formula semua anion yang terdapat dalam larutan itu. SO42–, OH– (b) Write the half equation for the reaction at the / Tuliskan persamaan setengah untuk tindak balas di 2+ (i) anode / anod : Cu Cu + 2e 2+ (ii) cathode / katod : Cu + 2e Cu (c) (i) From your observations, what happen to the intensity of the blue colour of the copper(II) sulphate solution during electrolysis?
Daripada pemerhatian anda, nyatakan apakah yang berlaku ke atas keamatan warna biru larutan kuprum(II) sulfat semasa proses elektrolisis?
The intensity of the blue colour of copper(II) sulphate remains unchanged.
(ii) Explain your answer / Jelaskan jawapan anda. The number of copper(II) ions become copper atoms at the cathode is equal to the number of copper atoms become copper(II) ions at the anode.
(d) If the experiment is repeated with the copper electrodes being replaced by carbon electrodes, state the name of the products formed at the Jika eksperimen diulangi dengan menggantikan elektrod kuprum dengan elektrod karbon, namakan hasil yang terbentuk di
5
(i)
anode / anod:
Oxygen
(ii) cathode / katod:
Copper
The diagram below shows the set-up of apparatus of an electrolytic cell. Rajah di bawah menunjukkan susunan radas bagi sel elektrolisis.
Carbon electrode P
Carbon electrode Q
Elektrod karbon P
Elektrod karbon Q
Copper(II) nitrate solution Larutan kuprum(II) nitrat
(a) Write the formula of all ions present in copper(II) nitrate solution. Tuliskan formula semua ion yang hadir dalam larutan kuprum(II) nitrat.
Cu2+, NO3–, H+ and OH– . (b) Write half equation for the reaction at / Tuliskan persamaan setengah di: 2+ electrode P / elektrod P : Cu + 2e Cu – electrode Q / elektrod Q : 4OH 2H2O + O2 + 4e (c) (i) What is the colour of copper(II) nitrate / Apakah warna larutan kuprum(II) nitrat?
Blue
(ii) What happens to the intensity of the colour of copper(II) nitrate solution? Explain your answer. Apakah yang berlaku kepada keamatan warna larutan kuprum(II) nitrat? Jelaskan jawapan anda.
The intensity of the blue colour of copper(II) nitrate decreases. The concentration of Cu2+ decreases because
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copper(II) ions receive electrons to form copper atom at the cathode.
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MODULE • Chemistry Form 4
ELECTROLYSIS IN INDUSTRY / ELEKTROLISIS DALAM INDUSTRI
Three uses of electrolysis in industries are / Tiga kegunaan elektrolisis dalam industri ialah:
1
Application Aplikasi
(a) Electroplating Penyaduran logam
Example
Electrolyte
Contoh
Silver electroplating
Elektrolit
Silver nitrate solution
Penyaduran perak
(b) Purification of metal Penulenan logam
(c) Metal extraction Pengekstrakan logam
Purification of copper
Molten aluminium oxide
Pengekstrakan aluminium
Cathode / Half equation
Anod / Persamaan setengah
Katod / Persamaan setengah
Anode / Anod: Silver metal
Cathode / Katod: Metal to be electroplated
Half equation / Persamaan setengah: Ag Ag+ + e
Half equation / Persamaan setengah: Ag+ + e Ag
Copper(II) Anode / Anod: sulphate solution Impure copper
Penulenan kuprum
Extraction of aluminium
Anode / Half equation
Cathode / Katod: Pure copper
Half equation / Persamaan setengah: Cu Cu2+ + 2e
Half equation / Persamaan setengah: Cu2+ + 2e Cu
Anode / Anod: Carbon
Cathode / Katod: Carbon
Half equation / Persamaan setengah: 2O2– O2 + 4e
Half equation / Persamaan setengah: Al3+ + 3e Al
The following diagram shows the aluminium extraction process.
2
Rajah di bawah menunjukkan proses pengekstrakan aluminium. Substance Z / Bahan Z
Substance Y Bahan Y
Substance X + cryolite Substance W
Bahan X + kriolit
Bahan W
(a) State the name of the following substances / Nyatakan nama bahan-bahan berikut: W : Liquid aluminium X : Molten aluminium oxide Y : Carbon Z : Carbon (b) Which substance acts as anode and cathode / Bahan yang manakah bertindak sebagai anod dan katod? Anode / Anod : Z Cathode / Katod : Y
(c) State the name of the product at anode and cathode / Namakan hasil yang diperoleh di anod dan katod. Anode / Anod : Oxygen Cathode / Katod : Aluminium (d) Write the ionic equation for the reactions at / Tuliskan persamaan ion bagi tindak balas yang berlaku di 2– 3+ anode / anod : 2O O2 + 4e cathode / katod : Al + 3e Al (e) Why is cryolite added to X / Mengapakan kriolit ditambah ke dalam X ? To lower down the melting point of aluminium oxide (from 2 045°C to 900°C ). The diagram below shows the set-up of apparatus used in the purification of copper.
3
Rajah di bawah menunjukkan susunan radas yang digunakan untuk proses penulenan kuprum.
Electrode X
Electrode Y
Elektrod X
Elektrod Y
Electrode Z
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Chemistry Form 4 • MODULE
(a) State the name of the substance used as / Nyatakan nama bahan yang dijadikan sebagai: electrode X / elektrod X : Impure copper
: Pure copper electrolyte Z / elektrolit Z : Copper(II) sulphate solution electrode Y / elektrod Y
(b) Write the half equation that occur at the / Tuliskan persamaan setengah yang berlaku di Cu Cu2+ + 2e electrode X / elektrod X : electrode Y / elektrod Y :
Cu2+ + 2e
Cu
(c) What are the observations at the / Apakah pemerhatian di electrode X / elektrod X : Electrode becomes thinner 4
electrode Y / elektrod Y : Brown solid deposited
To purify metal an impure metal / Untuk menulenkan logam tak tulen: (a) The impure metal is used as the anode / Logam tak tulen (b) The
pure metal
dijadikan sebagai anod.
Logam tulen
dijadikan sebagai katod. is used as the cathode / salt solution (c) The electrolyte used is an containing the ions of the purifying metal. Elektrolit adalah 5
larutan garam
yang mengandungi ion logam yang hendak ditulenkan.
A student intends to electroplate an iron spoon with copper. Describe a laboratory experiment to electroplate the iron ring. Your answer should involve the following: Seorang pelajar bercadang untuk menyadurkan sebatang sudu besi dengan kuprum. Huraikan satu eksperimen di dalam makmal untuk menyadur sebatang sudu besi. Jawapan anda perlu mengandungi: – A labelled diagram showing the set-up of apparatus / Rajah berlabel menunjukkan susunan radas. – Procedure / Kaedah. – Half equation for the reactions at both electrodes / Persamaan setengah untuk tindak balas di kedua-dua elektrod. – Observation at both electrodes / Pemerhatian di kedua-dua elektrod.
Answer / Jawapan:
Copper Iron spoon
Copper(II) nitrate solution
Procedure / Kaedah:
(a) Copper plate and iron spoon are cleaned with Kepingan kuprum dan sudu besi dibersihkan dengan
(b)
Copper(II) nitrate solution is poured into a Larutan kuprum(II) nitrat
(c)
sand paper
.
kertas pasir
.
beaker
dituangkan ke dalam bikar sehingga
until
half full
.
separuh penuh .
Iron spoon
is then connected to the negative terminal of battery while the copper plate is connected to the positive terminal of the battery// Iron spoon is made as cathode while copper plate is made as anode. Sudu besi bateri//
disambungkan kepada terminal negatif bateri dan Sudu besi dijadikan katod dan kepingan kuprum
kepingan kuprum
disambungkan kepada terminal positif
dijadikan anod.
(d) The iron spoon and the copper plate are dipped in the copper(II) nitrate solution as shown in the diagram. Sudu besi dan plat kuprum
(e) The circuit is
completed
dicelup
larutan kuprum(II) nitrat ke dalam / Litar dilengkapkan .
seperti ditunjukkan dalam rajah.
Cu2+ + 2e Cu . (f) Half equation at the cathode / Persamaan setengah di katod : (g) Observation of the cathode: Brown solid is deposited / Pemerhatian di katod: pepejal perang
terenap.
Cu Cu2+ + 2e
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(h) Half equation at the anode / Persamaan setengah di anod : . Copper plate becomes thinner (i) Observation of the anode / Pemerhatian di anod :
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MODULE • Chemistry Form 4
To electroplate an object with metal / Untuk menyadur sesuatu objek dengan logam: (a) The metal object to be electroplated is made to be cathode / Objek yang hendak disadur dijadikan anod anode .. (b) The electroplating metal is made to be / Logam penyadur dijadikan
6
katod
..
(c) The electrolyte used is an aqueous salt solution containing the ions of the electroplating metal. Elektrolit
yang digunakan adalah larutan akueus garam yang mengandungi ion logam penyadur.
ELECTROCHEMICAL SERIES / SIRI ELEKTROKIMIA
Electrochemical Series is an arrangement of positive ion.
1
Siri Elektrokimia ialah susunan
logam
metals
according to their tendency to release electrons to form a
mengikut kecenderungan melepaskan elektron membentuk ion bercas
positif
.
The position of metal atoms in Electrochemical Series / Kedudukan atom logam dalam Siri Elektrokimia: K, Na, Ca, Mg, Al, Zn , Fe, Sn ,Pb, Cu, Ag
2
Tendency of metal atom to release/donate electrons increases (electropositivity increases) Kecenderungan untuk atom logam melepaskan/menderma elektron bertambah (keelektropositifan bertambah)
The position of metal ions (cation) in the Electrochemical Series / Kedudukan ion logam (kation) dalam Siri Elektrokimia: K+, Na+, Ca2+, Mg2+, Al3+, Zn2+, Fe2+, Sn2+, Pb2+, *H+, Cu2+
3
Tendency of metal ion (cation) to receive/gain electrons increases Kecenderungan untuk ion logam (kation) untuk menerima elektron bertambah *H+ is also in the series of ion because it is present in aqueous solution of any electrolyte (salt solution/acid/alkali) * H+ juga terdapat dalam siri ion kerana kehadiran ion H+ dalam elektrolit larutan akueus (larutan garam/asid/alkali)
METAL DISPLACEMENT REACTION / TINDAK BALAS PENYESARAN LOGAM
The metal which is situated at a higher position (higher tendency to release electron) in the Electrochemical Series is able to displace metals below it from its salt solution .
1
Logam yang berada di kedudukan atas (kecenderungan melepaskan elektron yang tinggi) dalam Siri Elektrokimia dapat menyesarkan logam yang di bawahnya daripada larutan garam logam tersebut.
Example / Contoh:
2
Experiment / Eksperimen Silver nitrate solution Larutan argentum nitrat
Observation / Pemerhatian – Copper strip becomes thinner . Kepingan kuprum menipis .
– A grey deposited.
solid
Pepejal kelabu terenap.
– The colourless solution turns blue. Copper Kuprum
Larutan tidak berwarna bertukar menjadi biru.
Remark / Catatan Inference / Inferens: – The grey solid is Pepejal
kelabu
adalah
– The blue solution is Larutan biru adalah
silver
.
argentum
.
copper(II) nitrate
.
kuprum(II) nitrat .
Explanation / Penerangan: Silver ion receives electrons to form – Ion
argentum
silver
menerima elektron membentuk atom
– Copper atom releases electrons to form Atom kuprum melepaskan elektron membentuk
silver
– Copper has displaced Kuprum telah menyesarkan
Cu + 2AgNO3
atom.
argentum .
copper(II) ion ion kuprum(II)
. .
from silver nitrate solution.
argentum
dari larutan argentum nitrat.
Cu(NO3)2 + 2Ag .
– Copper is more electropositive than silver// Copper is above silver in the Electrochemical Series of metal.
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lebih elektropositif daripada argentum //Kuprum Kuprum adalah di atas terletak argentum dalam Siri Elektrokimia logam.
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Chemistry Form 4 • MODULE
– Magnesium strip becomes thinner .
Copper(II) sulphate solution
Kepingan magnesium menipis .
Larutan kuprum (II) sulfat
– The brown deposited.
Inference / Inferens: – The brown solid is copper . perang
Pepejal
solid
Pepejal perang terenap.
– The blue solution turn colourless. Larutan biru bertukar menjadi tidak berwarna.
Magnesium
adalah
kuprum
– The colourless solution is
.
magnesium sulphate magnesium sulfat
Larutan tidak berwarna adalah
. .
Explanation / Penerangan: – Copper(II) ion receives electrons to form copper atom. Ion
kuprum(II)
menerima elektron membentuk atom kuprum.
magnesium ion
– Magnesium atom releases electrons to form
ion magnesium
Atom magnesium melepaskan elektron membentuk
.
.
– Magnesium has displaced copper from copper(II) sulphate solution.
Magnesium
Magnesium telah menyesarkan
kuprum
dari larutan kuprum(II) sulfat.
MgSO4 + Cu
Mg + Cu SO4
.
more
electropositive than copper// Magnesium – Magnesium is above copper in the Electrochemical Series of metal. is Magnesium adalah di atas terletak
No observable changes.
Zinc nitrate solution
Tiada perubahan yang dapat diperhatikan.
Larutan zink sulfat
lebih
elektropositif daripada kuprum// magnesium kuprum dalam Siri Elektrokimia logam.
Inference / Inferens: – No reaction occur. Tiada tindak balas berlaku.
Explanation / Penerangan: – Copper cannot displace Kuprum
tidak boleh
zinc
menyesarkan
from zinc sulphate solution. zink
daripada larutan zink sulfat.
– Copper is more electropositive than zinc// Copper is zinc in the Electrochemical Series of metal.
below
Kuprum adalah kurang elektropositif daripada zink // kuprum terletak di bawah zink dalam Siri Elektrokimia logam.
Copper / Kuprum
VOLTAIC CELL (CHEMICAL CELL) / SEL RINGKAS (SEL KIMIA) 1
A cell that produces electrical energy when chemical reactions occur in it. Sel yang menghasilkan tenaga elektrik apabila berlaku tindak balas kimia di dalamnya.
2
electrical energy
Energy change in voltaic cell is chemical energy to
Perubahan tenaga dalam sel ringkas ialah dari tenaga kimia kepada 3
Produced when two
different
Terhasil apabila dua logam 4
5
.
metals are dipped in an electrolyte and are connected by an
berlainan
elektrolit
dicelup dalam
The voltage of chemical cell depends on the
distance
the further the distance between them, the
higher
Voltan sel kimia bergantung pada tinggi Elektrokimia, semakin
.
tenaga elektrik
jarak
dan disambung dengan
litar luar
external circuit
.
.
between the two metals in the Electrochemical Series, where is the voltage.
antara dua logam dalam Siri Elektrokimia di mana semakin jauh dua logam dalam Siri
voltannya.
A more electropositive metal becomes the positive terminal:
negative
negatif
sel. Logam yang kurang elektropositif akan menjadi terminal
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Logam yang lebih elektropositif akan menjadi terminal positif sel:
terminal of the cell. A less electropositive metal becomes the
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MODULE • Chemistry Form 4
Electrical current produced is detected by the galvanometer Electrical energy) (Chemical energy Arus elektrik terhasil dikesan oleh galvanometer (Tenaga kimia Tenaga elektrik)
Negative terminal / Terminal negatif • More electropositive metal.
G
:
_
Positive terminal / Terminal positif • Less electropositive metal.
+
Logam lebih elektropositif.
:
Logam kurang elektropositif.
• Metal atom will release electrons that will flow through the external circuit. Metal atom becomes metal ion (becomes thinner).
• The electrons that flow from the external circuit are received by the positive ion in the electrolyte through this terminal.
Atom logam akan melepaskan elektron yang akan mengalir di litar luar. Atom logam menjadi ion logam (semakin nipis).
Elektron yang akan mengalir dari litar luar diterima oleh ion positif dalam elektrolit melalui terminal ini.
Example of simple voltaic cell / Contoh voltan sel ringkas:
6
V
Magnesium
Copper
Magnesium
Kuprum
Copper(II) sulphate solution Larutan kuprum(II) sulfat
(a) Magnesium electrode is a negative terminal because magnesium is more electropositive than Elektrod magnesium adalah terminal
– Magnesium atom Atom magnesium
negatif
releases
melepaskan
kuprum :
elektron untuk membentuk ion magnesium, Mg2+.
– Magnesium electrode becomes
Mg Mg2+ + 2e
thinner
copper
kuprum
Elektron mengalir melalui litar luar ke elektrod
positive
.
/ Elektrod magnesium menjadi
– Electron flows through external circuit to the
Elektrod kuprum adalah terminal
daripada
:
electrons to form magnesium ion, Mg2+.
– Half equation / Persamaan setengah :
(b) Copper electrode is a
elektropositif
kerana magnesium lebih
copper
.
electrode.
.
electropositive
terminal because copper is less positif
nipis
kerana kuprum kurang
elektropositif
than
daripada
magnesium
:
magnesium
:
– Electrons from magnesium flow through external circuit to copper electrode. Elektron dari magnesium mengalir melalui litar luar ke elektrod kuprum.
–
Copper(II) ion in the electrolyte Ion
kuprum(II)
dalam elektrolit
receives
menerima
electron to form copper atom.
elektron untuk membentuk atom kuprum.
Cu + 2e Cu – Half equation / Persamaan setengah : . Brown solid is deposited on the surface of copper electrode. – +
Pepejal perang
terenap di permukaan elektrod kuprum.
(c) The concentration of copper(II) sulphate decreases because copper(II) ions discharged to copper atom at the positive terminal. The intensity of blue colour of copper(II) sulphate decreases.
Kepekatan larutan kuprum(II) sulfat berkurang warna biru larutan kuprum(II) sulfat berkurang.
kerana ion kuprum(II) dinyahcaskan kepada atom kuprum.
Keamatan
(d) If the magnesium metal is replaced with a zinc metal, the voltage reading decreases because zinc is nearer to copper in the electrochemical series.
m
berkurang
kerana zink lebih dekat dengan kuprum
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Chemistry Form 4 • MODULE
7
Daniell cell / Sel Daniell (a) It is an example of voltaic cell which consists of zinc electrode dipped in zinc sulphate solution, copper electrode dipped in copper(II) sulphate solution and connected by a salt bridge or porous pot. Merupakan satu contoh sel kimia yang terdiri daripada elektrod zink yang dicelup ke dalam larutan zink sulfat, elektrod kuprum dicelupkan ke dalam larutan kuprum(II) sulfat dan dihubungkan dengan titian garam atau pasu berliang. Zn / ZnSO4 // CuSO4 / Cu
(b) The function of porous pot or salt bridge is to allow the flow of ions through it so that the electric circuit is completed. Fungsi pasu berliang atau titian garam adalah untuk membenarkan ion-ion mengalir melaluinya dan melengkapkan litar.
(c) The diagram below shows the set-up of apparatus of Daniell cell. Rajah di bawah menunjukkan susunan radas bagi sel Daniell.
Sulphuric acid Asid sulfurik
Copper
Copper Copper(II) sulphate solution
Zinc sulphate
negative
Elektrod zink adalah terminal
– Zinc atom Atom zink
releases
melepaskan
terminal because zinc is more negatif
electropositive elektropositif
kerana zink adalah lebih
Pasu berliang
than
copper
daripada
kuprum
: :
electron to form zinc ion, Zn . 2+
elektron untuk membentuk ion zink, Zn2+.
Zn Zn2+ + 2e
– Half equation / Persamaan setengah : – Zinc electrode becomes
thinner
Elektrod kuprum adalah terminal
copper
kuprum
Elektron mengalir melalui litar luar ke elektrod
positive
. nipis
/ Elektrod zink menjadi
– Electrons flow through external circuit to the
(e) Copper electrode is a
Porous pot
Larutan kuprum(II) sulfat
Zink sulfat
(d) Zinc electrode is a
Zink sulfat
Copper(II) sulphate solution
Zink
Larutan kuprum(II) sulfat
Zinc / Zink Zinc sulphate
Kuprum
Zinc
Kuprum
electrode.
.
electropositive
terminal because copper is less positif
..
elektropositif
kerana kuprum kurang
than
daripada
zinc
:
zink
:
– Electrons from zinc electrode flow through external circuit to copper electrode. Elektron dari zink mengalir melalui litar luar ke elektrod kuprum.
–
Copper(II) ion in the electrolyte Ion
kuprum(II)
dalam elektrolit
receives
menerima
– Half equation / Persamaan setengah : –
electron to form copper atom.
elektron untuk membentuk atom kuprum.
Cu + 2e Cu 2+
.
Brown solid
is deposited on the surface of copper electrode.
Pepejal perang
terenap di permukaan elektrod kuprum.
(f) The concentration of copper(II) sulphate decreases because copper(II) ions are discharged to copper atoms. The intensity of blue colour of copper(II) sulphate decreases. Kepekatan larutan kuprum(II) sulfat berkurang warna biru kuprum(II) sulfat berkurang.
kerana ion kuprum(II) telah dinyahcaskan kepada atom kuprum.
Keamatan
(g) If zinc metal is replaced with a magnesium metal, the voltage reading increases because magnesium is further from copper in the Electrochemical Series.
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Jika logam zink digantikan dengan logam magnesium, bacaan voltan bertambah kerana jarak antara magnesium dengan kuprum jauh daripada jarak antara zink dengan kuprum dalam Siri Elektrokimia. lebih
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MODULE • Chemistry Form 4
Four main uses of the Electrochemical Series / Kegunaan utama Siri Elektrokimia: (a) To predict the terminal of chemical cell / Untuk meramalkan terminal sel kimia – The more electropositive metal is the negative terminal of the cell.
8
Logam yang lebih elektropositif ialah terminal negatif sel.
– The less electropositive metal is the positive terminal of the cell. Logam yang kurang elektropositif ialah terminal positif sel.
(b) To predict the voltage of chemical cell / Untuk meramalkan voltan sel kimia – The further the distance between two metals in the Electrochemical Series, the higher is the voltage of the chemical cell. Semakin jauh jarak antara dua logam dalam Siri Elektrokimia, semakin tinggi bacaan voltan sel kimia.
(c) To predict the metal displacement reactions / Untuk meramalkan tindak balas penyesaran logam – The more electropositive metal can displace a less electropositive metal from its salt solution. Logam yang lebih elektropositif dapat menyesarkan logam yang kurang elektropositif daripada larutan garamnya.
(d) To predict the selected ion to be discharged at the electrode in an electrolysis Untuk meramalkan pemilihan ion untuk dinyahcas di elektrod dalam proses elektrolisis
EXERCISE / LATIHAN
The table below shows the results of an experiment to construct the Electrochemical Series through the ability of metals to displace other metals from their salt solution.
1
Jadual di bawah menunjukkan keputusan eksperimen untuk membina Siri Elektrokimia berdasarkan keupayaan suatu logam untuk menyesarkan logam lain dari larutan garamnya. Experiment I / Eksperimen I
Experiment II / Eksperimen II
P nitrate solution
R nitrate solution
Larutan P nitrat
Larutan R nitrat
Zinc / Zink
Zinc / Zink
Metal P is displaced, blue colour solution turn colourless. Logam P disesarkan, larutan biru bertukar menjadi tanpa warna.
No reaction. Tiada tindak balas.
(a) Based on the results in the table, arrange metal P, zinc and R in descending order of electropositivity. Berdasarkan keputusan dalam jadual, susunkan logam P, zink dan R dalam tertib menurun keelektropositifan.
R, Zn, P (b) Based on the observation in Experiment I / Berdasarkan pemerhatian dalam Eksperimen I, (i) state the name the suitable metal P / namakan logam yang sesuai bagi P. Copper .
(ii) zinc can displace metal P from P nitrate solution. Explain. zink boleh menyesarkan logam P daripada larutan P nitrat. Terangkan.
Zinc is more electropositive than P. .
m
(iii) write the chemical equation for the reaction / tuliskan persamaan kimia untuk tindak balas. Zn + Cu(NO3 )2 Zn(NO3 )2 + Cu
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Chemistry Form 4 • MODULE
2
The diagram below shows the set-up of the apparatus to arrange metals W, X, Y and Z based on the potential difference of the metals. Rajah di bawah menunjukkan susunan radas bagi eksperimen untuk menentukan kedudukan logam W, X, Y dan Z berdasarkan beza upaya logam.
V Metal electrode
Metal electrode
Elektrod logam
Elektrod logam
Electrolyte / Elektrolit
The table below shows the results of the experiment. Jadual di bawah menunjukkan keputusan eksperimen. Pair of metals Pasangan logam
Potential difference (V)
Negative terminal
0.50
X
0.30
Y
1.10
Z
Beza keupayaan (V)
W and X W dan X
X and Y X dan Y
W and Z W dan Z
Terminal negatif
(a) Arrange metals W, X, Y and Z in descending order of the electropositivity of metal. Susunkan logam W, X, Y dan Z dalam tertib menurun keelektropositifan logam.
Z, Y, X, W . (b) (i)
Metals X and Z are used as electrodes in the diagram. State which metal acts as positive terminal. Logam X dan Z digunakan sebagai terminal dalam rajah. Nyatakan logam yang manakah akan bertindak sebagai terminal positif.
Metal X
(ii) Give reason for your answer in (b)(i) / Berikan sebab untuk jawapan anda di (b)(i). Metal X is less electropositive than metal Z. .
(c) Predict the voltage of the cell in (b)(i) / Ramalkan nilai voltan dalam sel di (b)(i). 0.6 V 3
The diagram below shows the set-up of apparatus for two types of cell. Rajah di bawah menunjukkan susunan radas untuk dua jenis sel.
Zinc
Copper
Copper
Zink
Kuprum
Kuprum
Copper(II) sulphate solution Larutan kuprum(II) sulfat
Cell Y / Sel Y
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Cell X / Sel X
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MODULE • Chemistry Form 4
Complete the following table to compare cell X and cell Y : Lengkapkan jadual berikut untuk membandingkan sel X dan sel Y : Description
Cell X
Cell Y
Electrolytic cell
Chemical cell
Perkara
Sel X
Type of cell Jenis sel
The energy change
Electrical energy
Perubahan tenaga
Ion presence in the electrolyte
Sel Y
Chemical energy
Chemical energy
Cu2+, H+, SO42–, OH–
Ion hadir dalam elektrolit
Electrical energy
Cu2+, H+, SO42–, OH–
Electrode
Anode / Anod: Copper
Negative terminal / Terminal negatif : Zinc
Elektrod
Cathode / Katod: Copper
Positive terminal / Terminal positif : Copper
Half equation
Anode / Anod: Cu
Negative terminal / Terminal negatif : Zn
Persamaan setengah
Cu2+ + 2e
2+ Cathode / Katod: Cu + 2e
Cu
Zn2+ + 2e
2+ Positive terminal / Terminal positif : Cu + 2e
Cu
Observation
Anode / Anod:
Negative terminal / Terminal negatif :
Pemerhatian
Copper electrode becomes thinner
Zinc electrode becomes thinner
Cathode / Katod: Brown solid deposited
Positive terminal / Terminal positif :
Electrolyte / Elektrolit:
Electrolyte / Elektrolit:
Intensity blue colour of copper(II) sulphate
Intensity blue colour of copper(II) sulphate decreases
Brown solid deposited
remains unchanged
The diagram below shows the set-up of apparatus for an experiment.
4
Rajah di bawah menunjukkan susunan radas bagi suatu eksperimen.
V
–
+
Zinc / Zink
Anode
Cathode Copper
Copper
Kuprum
Kuprum
Zinc sulphate solution
Copper(II) sulphate solution
Larutan zink sulfat Pasu berliang
Larutan kuprum(II) sulfat
Cell A / Set A
(a)
Larutan kuprum(II) sulfat
Porous pot
Copper(II) sulphate solution
Cell B / Set B
In the above diagram, label Dalam gambar rajah di atas, label
(i) (ii)
the positive terminal and negative terminal Cell A, terminal positif dan terminal negatif bagi Sel A,
anode and cathode in Cell B. anod dan katod bagi Sel B.
(b) What is the energy change in Cell A and Cell B?
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Cell A / Sel A : Chemical energy to electrical energy
Cell B / Sel B : Electrical energy to chemical energy
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Chemistry Form 4 • MODULE
(c) What is the function of the porous pot in cell A? Apakah fungsi pasu berliang dalam Sel A?
To allow the movement of ions through it. (d) Referring to Cell A. Merujuk kepada Sel A.
(i)
What is the observation at zinc electrode?
Apakah pemerhatian di elektrod zink?
Zinc electrode becomes thinner.
(ii) Write the half equation for the reaction at zinc electrode. Tuliskan persamaan setengah untuk tindak balas di elektrod zink.
Zn
Zn2+ + 2e
(iii) What is the observation at copper electrode / Apakah pemerhatian di elektrod kuprum? Brown solid deposited.
(iv) Write the half equation for the reaction at copper electrode. Tuliskan persamaan setengah untuk tindak balas di elektrod kuprum.
Cu2+ + 2e
Cu .
(v) After 30 minutes, what is the colour change of the copper(II) sulphate solution? Explain why. Selepas 30 minit, apakah perubahan warna larutan kuprum(II) sulfat? Jelaskan mengapa.
– The intensity of blue colour decreases. – Copper(II) ions are discharged to form copper atoms. – Concentration of copper(II) ions in copper(II) sulphate decreases. (e) Referring to Cell B. Merujuk kepada Sel B.
(i)
What is the observation at the anode? Apakah pemerhatian di anod?
Copper electrode becomes thinner.
(ii) Write the half equation for the reaction at the anode. Tuliskan persamaan setengah untuk tindak balas di anod.
Cu
Cu2+ + 2e
(iii) What is the observation at the cathode? Apakah pemerhatian di katod?
Brown solid deposited.
(iv) Write the half equation for the reaction at copper electrode. Tuliskan persamaan setengah untuk tindak balas di katod.
Cu2+ + 2e
Cu
(f) The intensity of blue colour of copper(II) sulphate solution in the Cell B remains unchanged during the experiment. Explain why. Keamatan warna biru larutan kuprum(II) sulfat dalam Sel B tidak berubah semasa eksperimen. Jelaskan mengapa.
– The concentration of copper(II) sulphate remain unchanged. – The rate of copper(II) ions discharged to copper atom at the cathode equals to the rate of copper atoms form
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copper(II) ions at the anode.
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MODULE • Chemistry Form 4
Objective Questions / Soalan Objektif 1
Which of the following is an electrolyte? Antara berikut, yang manakah adalah elektrolit?
C
Copper electrode becomes thicker
Copper electrode becomes thinner
Elektrod kuprum semakin tebal
Elektrod kuprum semakin nipis
D
Gas bubbles are released
Copper electrode becomes thicker
A Glacial ethanoic acid Asid etanoik glasial
B
Molten naphthalene
C
Aqueous solution of zinc chloride
Naftalena lebur
Elektrod kuprum semakin tebal
Larutan akueus zink klorida
4
D Hydrogen chloride in methylbenzene Hidrogen klorida dalam metilbenzena
2
Gelembung gas dibebaskan
The diagram below shows the set-up of apparatus of an electrolysis process. Rajah di bawah menunjukkan sususnan radas untuk proses elektrolisis.
The diagram below shows the set-up of apparatus used to electrolyse substance X.
Electrolyte
Rajah di bawah menunjukkan susunan radas untuk elektrolisis bahan X.
Elektrolit
Carbon electrode
P
Elektrod karbon
Q
Carbon electrode Elektrod karbon
Carbon electrodes Elektrod karbon
Which of the following electrolytes produce oxygen gas at electrode Q?
Substance X
Antara elektrolit berikut, yang manakah membebaskan gas oksigen pada elektrod Q?
Bahan X
I
Heat
Asid hidroklorik 1.0 mol dm–3
Panaskan
3
1.0 mol dm–3 hydrochloric acid
II
1.0 mol dm–3 sulphuric acid Asid sulfurik 1.0 mol dm–3
Which of the following compounds can light up the bulb when used as substance X?
III 1.0 mol dm–3 potassium iodide solution
Antara berikut, yang manakah boleh menyalakan mentol apabila digunakan sebagai bahan X? A Copper(II) nitrate / Kuprum(II) nitrat B Lead(II) iodide / Plumbum(II) iodida C Zinc carbonate / Zink karbonat D Sodium carbonate / Natrium karbonat
IV 1.0 mol dm–3 nitric acid
The diagram below shows the set-up of apparatus for electrolysis of copper(II) sulphate solution. Rajah di bawah menunjukkan susunan radas untuk elektrolisis larutan kuprum(II) sulfat.
Larutan kalium iodida 1.0 mol dm–3
A B C D 5
Asid nitrik 1.0 mol dm–3 I and II only / I dan II sahaja II and III only / II dan III sahaja II and IV only / II dan IV sahaja II, III and IV only / II, III dan IV sahaja
The table below shows the observation of electrolysis of a substance Q using carbon electrode. Jadual di bawah menunjukkan pemerhatian bagi elektrolisis bahan Q menggunakan elektrod karbon.
Electrode
Observation
Elektrod
Copper electrode X
Copper electrode Y Elektrod kuprum Y
Elektrod kuprum X
Copper(II) sulphate solution
Anode
A greenish-yellow gas released
Anod
Gas kuning kehijauan terbebas
Cathode
A colorless gas which burns with a ‘pop’ sound is released
Katod
Gas tanpa warna terbakar dengan bunyi ‘pop’ dibebaskan
Larutan kuprum(II) sulfat
What can be observed at the electrodes X and Y after 30 minutes? Apakah yang dapat diperhatikan pada elektrod X dan Y selepas 30 minit?
A
B
X
Y
Copper electrode becomes thinner
Copper electrode becomes thicker
Elektrod kuprum semakin nipis
Elektrod kuprum semakin tebal
Copper electrode becomes thinner
Gas bubbles are released
Pemerhatian
What is substance Q? Apakah bahan Q?
A B C D
1.0 mol dm–3 of hydrochloric acid. Asid hidroklorik 1.0 mol dm–3.
1.0 mol dm–3 of potassium nitrate solution. Larutan natrium nitrat 1.0 mol dm–3.
1.0 mol dm–3 of copper(II) chloride solution. Larutan kuprum(II) klorida 1.0 mol dm–3.
1.0 mol dm–3 of magnesium bromide solution. Larutan magnesium bromida 1.0 mol dm–3.
Gelembung gas dibebaskan
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Elektrod kuprum semakin nipis
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Chemistry Form 4 • MODULE
6
The diagram below shows the set-up of apparatus of a chemical cell that shows the direction of electron flow from zinc to metal Q.
8
The table below shows the information about three voltaic cells. Jadual di bawah menunjukkan maklumat tentang tiga sel kimia.
Rajah di bawah menunjukkan susunan radas sel kimia yang menunjukkan arah pengaliran elektron ke logam Q.
Pair of metals Pasangan logam
Q
Zinc Zink
Larutan natrium klorida cair
A B
Apakah logam Q?
B C D
Copper
9
Iron
Beza upaya (V)
Terminal positif
W, Z
Z
3.1
X, Y
Y
0.3
W, X
X
1.8
Apakah beza upaya sel kimia apabila logam Y dipasangkan dengan logam Z?
What is metal Q? Kuprum
Potential difference (V)
What is the potential difference of the voltaic cell when metal Y is paired with metal Z?
Dilute sodium chloride solution
A
Positive terminal
C D
1.0 V 1.3 V
2.1 V 2.8 V
The diagram below shows the set-up of apparatus in a chemical cell and electrolytic cell. Rajah di bawah menunjukkan susunan radas bagi sel kimia dan sel elekrolisis.
Besi
Aluminium Aluminium
Magnesium Magnesium
7
The diagram below shows the set-up of apparatus used to purify impure copper by using electrolysis method. Rajah di bawah menunjukkan susunan radas yang digunakan untuk menulenkan kuprum tak tulen dengan menggunakan kaedah elektrolisis.
P
Zinc
Elektrolit Z
A B C
Antara berikut, yang manakah adalah kedudukan yang betul untuk kuprum tulen dan kuprum tak tulen?
D
A
Elektrod Y
Impure copper
Pure copper
Kuprum tak tulen
Kuprum tulen
Electrolyte Z Elektrolit Z
Copper(II) sulphate solution Larutan kuprum(II) sulfat
B
Pure copper
Impure copper
Kuprum tulen
Kuprum tak tulen
Kuprum
Zinc sulphate solution
Which of the following shows the correct position of pure copper and impure copper?
Electrode Y
Copper
Copper(II) sulphate solution Larutan kuprum(II) sulfat
Antara berikut, yang manakah merupakan pemerhatian pada elektrod R?
Electrolyte Z
Elektrod X
S
Which of the following is the observation at electrode R?
Y
Electrode X
R
Copper Kuprum
Larutan zink sulfat
X
Q
Zink
Pure copper
Sulphuric acid
Kuprum tak tulen
Kuprum tulen
Asid sulfurik
D
Pure copper
Impure copper
Sulphuric acid
Kuprum tulen
Kuprum tak tulen
Asid sulfurik
A colourless gas is released Gas tanpa warna terbebas
A brown solid is deposited Pepejal perang terenap
Jadual di bawah menunjukkan keputusan eksperimen untuk mengkaji penyesaran logam daripada larutan garamnya menggunakan logam lain.
Metal Logam P
Larutan kuprum(II) sulfat
Impure copper
Electrode R becomes thicker Elektrod R semakin tebal
10 The table below shows the results of an experiment to study the displacement of metal from its solution using other metals.
Copper(II) sulphate solution
C
Electrode R becomes thinner Elektrod R semakin nipis
Q
Nitrate of Q Nitrat bagi Q
Nitrate of S Nitrat bagi S
–
– reaction occur / tindak balas berlaku – no reaction / tiada tindak balas Which of the following is the arrangement of metals P, Q and R in ascending order of the tendency of the metals to form ions? Antara berikut, yang manakah adalah susunan logam P, Q dan R dalam susunan menaik kecenderungan logam membentuk ion?
P, S, Q Q, S, P
C D
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MODULE • Chemistry Form 4
6
ACID AND BASES ASID DAN BES
ACID AND BASES / ACID DAN BES • ACID / ASID – To state the meaning of acid, give examples and write chemical equations and observations for the reaction of acids: Menyatakan maksud asid, memberi contoh dan menulis persamaan tindak balas kimia dan pemerhatian bagi tindak balas asid: (i) with carbonates / dengan karbonat (ii) with metals / dengan logam (iii) with bases / dengan bes • BASICITY OF AN ACID / KEBESAN ASID – To state the meaning of basicity of an acid and to write equations for the ionisation of monoprotic and diprotic acids. Menyatakan maksud kebesan asid dan menulis persamaan pengionan asid monoprotik dan diprotik. – To relate the basicity of acid/alkali with pH values / Mengaitkan kebesan asid /alkali dengan nilai pH. • BASE / ALKALI / BES / ALKALI – To state the meaning of base and to correlate base with alkali / Menyatakan maksud bes dan mengaitkan bes dengan alkali. – To write chemical equations involving alkalis with acids and ammonium salts. Menulis persamaan tindak balas kimia alkali dengan asid dan dengan garam ammonium.
ROLE OF WATER IN ACIDS AND ALKALI / PERANAN AIR DALAM ASID DAN ALKALI – To explain why the acid and alkali properties are shown in the presence of water. Menerangkan mengapa sifat asid dan alkali ditunjukkan dengan kehadiran air.
– To explain why the acid and alkali properties do not show in the absence of water or in non-water solvent. Menerangkan mengapa sifat asid dan alkali tidak ditunjukkan tanpa kehadiran air atau dalam pelarut bukan air.
pH SCALE / SKALA pH – To state the meaning of pH / Menyatakan maksud pH. – To relate the pH value with the concentration of H+ ion for the acids and OH– ions for alkalis. Mengaitkan nilai pH dengan kepekatan ion H+ bagi asid dan ion OH– bagi alkali.
• STRONG / WEAK ACID AND STRONG / WEAK ALKALI / ASID KUAT / LEMAH DAN ALKALI KUAT / LEMAH – To list examples and equations for the ionisation of strong / weak acid and strong / weak alkali. Menyenaraikan contoh dan menulis persamaan pengionan bagi asid kuat / lemah dan alkali kuat / lemah. – To relate the pH value with the strength of acid / alkali / Mengaitkan nilai pH dengan kekuatan asid / alkali.
ACID AND ALKALI CONCENTRATION / KEPEKATAN ASID DAN ALKALI – To state the meaning of concentration in g dm–3 and mol dm–3 / Menyatakan maksud kepekatan dalam unit g dm–3 dan mol dm–3. – To state the meaning of standard solution and to describe the preparation of standard solution. Menyatakan maksud larutan piawai dan menghuraikan eksperimen penyediaan larutan piawai. MV . – To solve various problems with calculations related to the preparation of standard solution using n = 1 000 Menyelesaikan pelbagai masalah pengiraan berkaitan penyediaan larutan piawai menggunakan formula n = MV . 1 000
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• NEUTRALISATION OF ACID AND ALKALI / TINDAK BALAS PENEUTRALAN ASID DAN ALKALI – To describe the titration of acid with alkali and to calculate acid / alkali concentrations if a standard solution are given. Menghuraikan titratan asid dengan alkali dan menghitung kepekatan asid / alkali jika satu larutan piawai diberikan. – To describe the type of indicators used and the colour changes at the end-point. Menyatakan jenis penunjuk yang digunakan dan perubahan warna penunjuk pada takat akhir. – To solve numerical problems involving neutralisation / Menyelesaikan masalah pengiraan berkaitan peneutralan.
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Chemistry Form 4 • MODULE
ACID / ASID 1 2
Acid is a chemical substance which ionises in water to produce hydrogen ion. Asid ialah bahan kimia yang mengion dalam air menghasilkan ion hidrogen.
Acid tastes sour and turns moist blue litmus to red. Asid mempunyai rasa yang masam dan menukar kertas litmus biru lembap menjadi merah.
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Example of acid is hydrochloric acid / Contoh asid ialah asid hidroklorik : (a) Hydrogen chloride gas is a *covalent compound exist in the form of molecule. Gas hidrogen klorida ialah *sebatian kovalen wujud dalam bentuk molekul.
(b) As hydrogen chloride dissolves in water, hydrogen chloride molecule ionises to hydrogen ion and chloride ion in aqueous solution. This aqueous solution is called hydrochloric acid. Apabila hidrogen klorida melarut dalam air, molekul hidrogen klorida mengion kepada ion hidrogen dan ion klorida dalam larutan akueus. Larutan akueus itu dipanggil asid hidroklorik.
HCl (aq / ak ) Hydrochloric acid / Asid hidroklorik
H+ (aq / ak ) Hydrogen ion / Ion hidrogen
+
Cl– (aq / ak ) Chloride ion / Ion klorida
(c) An aqueous hydrogen ion, H+(aq) is actually the hydrogen ion combined with water molecule to form hydroxonium ion, H3O+. However this ion can be written as H+. Ion hidrogen akueus, H+(ak) ialah ion hidrogen yang bergabung dengan molekul air membentuk ion hidroksonium, H3O+. Walau bagaimanapun, ion ini boleh ditulis sebagai H+. HCl (g) + H2O(l/ce) H3O+ (aq/ak ) + Cl– (aq/ak )
Hydrogen chloride
Ion hydroxonium Ion klorida
Hidrogen klorida
Ion hidroksonium
H3O+ Ion hydroxonium 4
H+(aq/ak ) Ion hidrogen
Ion hidroksonium
The ionisation of hydrochloric acid is represented as:
Ion klorida
Pengionan asid hidroklorik diwakili oleh: HCl (aq/ak) H+ (aq/ak) + Cl– (aq/ak)
+ H2O
Ion hidrogen
Basicity of an acid is the number of ionisable of hydrogen atom per molecule of an acid molecule in an aqueous solution / Kebesan asid ialah bilangan atom hidrogen yang boleh mengion bagi setiap molekul asid dalam larutan akueus.
– Monoprotic: One acid molecule ionises to Monoprotik: Satu molekul asid mengion kepada
one
hydrogen ion.
satu
ion hidrogen.
– Diprotic: One acid molecule ionises to
two
hydrogen ion.
Diprotik: Satu molekul asid mengion kepada
dua
ion hidrogen.
– Triprotic: One acid molecule ionises to
three
Triprotik: Satu molekul asid mengion kepada
tiga
hydrogen ion. ion hidrogen.
Hydrochloric is monoprotic acid because one molecule of hydrochloric acid ionises to Asid hidroklorik ialah sejenis asid monoprotik kerana satu molekul asid hidroklorik mengion kepada 5
one satu
hydrogen ion. ion hidrogen.
Examples of acid and their basicity / Contoh-contoh asid dan kebesannya: Ionisation of acid Pengionan asid
HNO3 (aq/ak ) Nitric acid
– + NO3 (aq) Hydrogen ion Nitrate ion
Ion hidrogen
H2SO4 (aq/ak ) Sulphuric acid
2– + SO4 (aq) Hydrogen ion Sulphate ion
Asid sulfurik
H3PO4 (aq/ak ) Phosphoric acid *CH3COOH (aq/ak ) Ethanoic acid Asid etanoik
3H+(aq) Hydrogen ion
Asid fosforik
Ion hidrogen
Kebesan asid
One
Monoprotic
Two
Diprotic
Three
Triprotic
One
Monoprotic
Ion nitrat
2H+(aq)
Ion hidrogen
Basicity of acid
Bilangan ion hidrogen dihasilkan bagi setiap molekul asid
H+(aq)
Asid nitrik
Number of hydrogens ion produce per molecule of acid
Ion sulfat
3– + PO4 (aq) Phosphate ion
Ion fosfat
CH3COO–(aq) + H+(aq) Ethanoate ion Hydrogen ion Ion etanoat
Ion hidrogen n io
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*Not all hydrogen atoms in ethanoic acid are ionisable / *Bukan semua ion hidrogen dalam asid etanoik boleh mengion
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MODULE • Chemistry Form 4
BASES / BES Bases is a chemical substance that reacts with acid to produce salt and water only. For example, Bes ialah sejenis bahan kimia yang bertindak balas dengan asid menghasilkan garam dan air sahaja. Contohnya,
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(a) Copper(II) oxide (a base) reacts with sulphuric acid to produce copper(II) sulphate (a salt) and water. Kuprum(II) oksida (bes) bertindak balas dengan asid sulfurik menghasilkan kuprum(II) sulfat (garam) dan air.
CuO + H2SO4
CuSO4
+
H2O
(b) Zinc hydroxide (a base) reacts with hydrochloric acid to produce zinc chloride (a salt) and water. Zink hidroksida (bes) bertindak balas dengan asid hidroklorik menghasilkan zink klorida (garam) dan air.
ZnCl2 H2O Zn(OH)2 + 2HCl + Most bases are metal oxide or metal hydroxide which are ionic compound. Example of bases are magnesium oxide, zinc oxide, sodium hydroxide and potassium hydroxide.
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Kebanyakan bes ialah oksida logam atau hidroksida logam yang merupakan sebatian ion. Contoh-contoh bes ialah magnesium oksida, zink oksida, natrium hidroksida dan kalium hidroksida.
The bases that can dissolve in water (soluble bases) are known as alkali.
3
Bes yang boleh melarut dalam air (bes larut) dikenali sebagai alkali.
Sodium hydroxide and potassium hydroxide are soluble in water and they are called alkali whereas magnesium oxide and zinc oxide are called bases as they are insoluble in water.
4
Natrium hidroksida dan kalium hidroksida larut dalam air dan dipanggil sebagai alkali manakala magnesium oksida dan zink oksida dipanggil sebagai bes kerana tidak terlarut dalam air. Alkali is a base that is soluble in water and ionises to hydroxide ion. For example, Alkali ialah bes yang larut dalam air dan mengion kepada ion hidroksida. Contohnya,
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(a) Sodium hydroxide dissolves in water and ionises to hydroxide ion. Natrium hidroksida terlarut dalam air dan mengion kepada ion hidroksida.
NaOH (aq/ak ) Na+ (aq/ak ) + OH– (aq/ak ) (b) Ammonia solution is obtained by dissolving ammonia molecule in water, ionisation occur to produce a hydroxide ion, OH–. Larutan ammonia diperoleh dengan melarutkan molekul ammonia dalam air, pengionan berlaku menghasilkan ion hidroksida, OH–. – NH3 (g) + H2O (l/ce ) NH+ 4 (aq/ak ) + OH (aq/ak )
(c) Other examples of alkalis are barium hydroxide and calcium hydroxide. Contoh alkali lain adalah barium hidroksida dan kalsium hidroksida.
Alkali tastes bitter, slippery and turns moist red litmus to blue.
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Alkali mempunyai rasa yang pahit, licin dan menukarkan kertas litmus merah lembap kepada biru.
EXERCISE / LATIHAN
Complete the following table / Lengkapkan jadual berikut : Soluble base (alkali) / Bes terlarut (alkali) Name / Nama Sodium oxide Natrium oksida
Potassium oxide Kalium oksida
Ammonia Ammonia
Sodium hydroxide Natrium hidroksida
Potassium hydroxide Kalium hidroksida
Barium hydroxide Barium hidroksida
Formula / Formula
Ionisation equation / Persamaan pengionan
Na2O
Na2O(s) + H2O 2NaOH(aq) NaOH(aq) Na+ (aq) + OH– (aq)
K2O
K2O(s) + H2O 2KOH(aq) KOH(aq) K+ (aq) + OH– (aq)
NH3
NH3(g)+ H2O
NaOH
NaOH(aq)
KOH
KOH(aq)
Ba(OH)2
Ba(OH)2(aq)
NH4+(aq) + OH–(aq) Na+ (aq) + OH– (aq) K+ (aq) + OH– (aq) Ba2+(aq) + 2OH– (aq)
Insoluble base / Bes tak terlarut Name / Nama
Formula / Formula
Copper(II) oxide Kuprum(II) oksida
Copper(II) hydroxide Kuprum(II) hidroksida
Zinc hydroxide Zink hidroksida
Aluminium oxide Aluminium oksida
Lead(II) hydroxide Plumbum(II) hidroksida
Magnesium hydroxide Magnesium hidroksida
CuO Cu(OH)2 Zn(OH)2 Al2O3 Pb(OH)2 Mg(OH)2
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Bases that can dissolve in water (soluble bases) are known as alkali / Bes yang larut dalam air (bes larut) dipanggil alkali m
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Chemistry Form 4 • MODULE
CHEMICAL PROPERTIES OF ACID / SIFAT-SIFAT KIMIA ASID 1
Acid react with metal, base / alkali and metal carbonate / Asid bertindak balas dengan logam, bes/alkali dan karbonat logam: Chemical properties Sifat-sifat kimia
1 Acid + Metal Asid + Logam
Salt + Hydrogen
Garam + Hidrogen
Example of experiment Contoh eksperimen
Zinc + Hydrochloric acid Zink + Asid hidroklorik
Observation Pemerhatian
Remark Catatan
– The grey solid Chemical equation: Persamaan kimia: dissolves. Pepejal kelabu Mg + 2HCl MgCl2 + H2
* Acid react with the metals that are terlarut. Lighted wooden more electropositive than hydrogen – Gas bubbles splinter in electrochemical series, acids do not Inference / Inferens : are released. Kayu uji menyala react with copper and silver (type of – Magnesium reacts with When a Hydrochloric acid reaction is displacement, the metals hydrochloric acid. burning Asid hidroklorik that are placed above hydrogen in wooden Magnesium bertindak balas Electrochemical Series can displace Magnesium powder dengan asid hidroklorik. splinter is hydrogen from acid) Serbuk magnesium placed at the – Hydrogen gas is * Asid bertindak balas dengan logam-logam mouth of the yang lebih elektropositif daripada hidrogen (a) About 5 cm3 of dilute released. test tube, dalam Siri Elektrokimia, asid tidak bertindak hydrochloric acid is poured Gas hidrogen terbebas. balas dengan kuprum dan argentum (jenis ‘pop sound’ is into a test tube. tindak balas ialah penyesaran, logam-logam produced. Sebanyak 5 cm3 asid hidroklorik di atas hidrogen dalam Siri Elektrokimia boleh menyesarkan hidrogen daripada asid)
* Application of the reaction: * Aplikasi tindak balas:
– Preparation of soluble salt (Topic Salt) Penyediaan garam terlarut (Tajuk Garam)
– Preparation of hydrogen gas in determination of the empirical formula of copper(II) oxide (Topic Chemical Formula and Equation) Penyediaan gas hidrogen dalam menentukan formula empirik kuprum(II) oksida (Tajuk Formula dan Persamaan Kimia)
2 Acid + Metal carbonate Water + Carbon dioxide Asid + Karbonat logam Karbon dioksida
Salt +
Garam + Air +
cair dimasukkan ke dalam tabung uji.
(b) One spatula of magnesium powder is added to the acid. Satu spatula serbuk magnesium ditambah kepada asid.
(c) A burning wooden splinter is placed at the mouth of the test tube. Kayu uji menyala diletakkan pada mulut tabung uji.
(d) The observations are recorded. Semua pemerhatian direkodkan.
Calcium carbonate + Nitric acid Kalsium karbonat + Asid nitrik Hydrochloric acid Asid hidroklorik
Lime water Air kapur
*Application of the reaction: *Aplikasi tindak balas:
– Preparation of soluble salt (Topic Salt) Penyediaan garam terlarut (Tajuk Garam)
– Confirmatory test for anion carbonate ion in qualitative analysis of salt (Topic Salt) Ujian pengesahan bagi ion karbonat dalam analisis kualitatif garam (Tajuk Garam)
Gelembung gas dibebaskan. Apabila kayu uji menyala didekatkan pada mulut tabung uji, bunyi ‘pop’ dihasilkan.
Calcium carbonate / Kalsium karbonat
(a) About 5 cm3 of dilute hydrochloric acid is poured into a test tube. Sebanyak 5 cm3 asid hidroklorik cair dimasukkan ke dalam tabung uji.
(b) One spatula of calcium carbonate powder is added into the test tube. Satu spatula serbuk kalsium karbonat dimasukkan ke dalam asid.
– The white solid dissolves. Pepejal putih terlarut.
Chemical equation: Persamaan kimia:
CaCO3 + 2HCl
CaCl2 + H2O + CO2 – Gas bubbles are released. Inference / Inferens : When the – Calcium carbonate gas passed reacts with nitric acid. through lime Kalsium karbonat water, the lime bertindak balas dengan water turns asid hidroklorik. chalky. Gelembung gas – Carbon dioxide gas terbebas. Apabila is released. gas tersebut dilalukan melalui air kapur, air kapur menjadi keruh.
Gas karbon dioksida terbebas.
(c) The gas released is passed through lime water as shown in the diagram. Gas yang dibebaskan dilalukan melalui air kapur seperti ditunjukkan dalam rajah.
(d) The observations are recorded. n io
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Semua pemerhatian direkodkan.
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MODULE • Chemistry Form 4
3 Acid + Base / Alkali Asid + Bes / Alkali
Salt + Water
Garam + Air
*Acid neutralises base/alkali
Copper(II) oxide + Sulphuric acid Kuprum(II) oksida + Asid sulfurik Sulphuric acid / Asid sulfurik
– The black solid dissolves.
Persamaan kimia:
CuO + H2SO4
Pepejal hitam terlarut.
* Asid meneutralkan bes/alkali
*Application of the reaction: *Aplikasi tindak balas:
– Preparation of soluble salt (Topic Salt) Penyediaan garam terlarut (Tajuk Garam)
Chemical equation:
Copper(II) oxide / Kuprum(II) oksida
CuSO4 + H2O
– The colourless solution turns Inference / Inferens : blue. – Copper(II) oxide reacts Larutan tanpa with sulphuric acid. warna bertukar
(a) Dilute hydrochloric acid is poured into a beaker until half full.
menjadi biru.
Asid hidroklorik cair dimasukkan dalam bikar hingga separuh penuh.
(b) The acid is warmed gently. Asid dihangatkan.
(c) One spatula of copper(II) oxide powders added to the acid.
Kuprum(II) oksida bertindak balas dengan asid sulfurik.
– The blue solution is copper(II) sulphate . Larutan biru tersebut ialah kuprum(II) sulfat .
Satu spatula serbuk kuprum(II) oksida ditambahkan kepda asid tersebut.
(d) The mixture is stirred with a glass rod. Campuran dikacau dengan rod kaca.
(e) The observations are recorded. Semua pemerhatian direkodkan.
Write the chemical formulae for the following compounds / Tuliskan formula kimia bagi sebatian berikut:
2
Compound / Sebatian Hydrochloric acid Asid hidroklorik
Nitric acid Asid nitrik
Sulphuric acid Asid sulfurik
Ethanoic acid Asid etanoik
Sodium hydroxide Natrium hidroksida
Potassium hydroxide Kalium hidroksida
Calcium hydroxide Kalsium hidroksida
Sodium carbonate Natrium karbonat
Magnesium hydroxide Magnesium hidroksida
Ammonium sulphate Ammonium sulfat
Hydroxide ion Ion hidroksida
Sodium sulphate Natrium sulfat
Carbon dioxide Karbon dioksida
Copper(II) carbonate Kuprum(II) karbonat
Water
m
HCl HNO3 H2 SO4 CH3COOH NaOH KOH Ca(OH)2 Na2CO3 Mg(OH)2 (NH4 )2SO4 OH– Na2 SO4 CO2 CuCO3 H2O
Compound / Sebatian Magnesium oxide Magnesium oksida
Calcium oxide Kalsium oksida
Copper(II) oxide Kuprum(II) oksida
Lead(II) oxide Plumbum(II) oksida
Sodium nitrate Natrium nitrat
Potassium sulphate Kalium sulfat
Barium hydroxide Barium hidroksida
Sodium chloride Natrium klorida
Magnesium Magnesium
Zinc Zink
Sodium Natrium
Calcium carbonate Kalsium karbonat
Hydrogen gas Gas hidrogen
Sodium oxide Natrium oksida
Magnesium nitrate Magnesium nitrat
Chemical formulae / Formula kimia MgO CaO CuO PbO NaNO3 K2 SO4 Ba(OH)2 NaCl Mg Zn Na CaCO3 H2 Na2O Mg(NO3 )2
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Air
Chemical formulae / Formula kimia
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Chemistry Form 4 • MODULE
3
Ionic equation / Persamaan ion :
Ionic equation shows particles that change during chemical reaction. Persamaan ion menunjukkan zarah yang berubah semasa tindak balas kimia.
Example / Contoh : (i) Reaction between sulphuric acid and sodium hydroxide solution: Tindak balas antara asid sulfurik dengan larutan natrium hidroksida: Write balanced equation / Tulis persamaan seimbang :
H2SO4 + 2NaOH
Na2SO4 + 2H2O
Write the formula of all the particles in the reactants and products: Tulis formula bagi semua zarah dalam bahan tindak balas dan hasil tindak balas:
2H+ + SO42– + 2Na+ + 2OH–
Remove all the particles in the reactants and products which remain unchanged: Keluarkan semua zarah dalam bahan dan hasil tindak balas yang tidak berubah:
2H+ + SO42– + 2Na+ + 2OH–
Ionic equation / Persamaan ion :
2H+ + 2OH–
2Na+ + SO42– + 2H2O
2Na+ + SO42– + 2H2O
2H2O ⇒ H+ + OH–
H2O
(ii) Reaction between zinc oxide and hydrochloric acid / Tindak balas antara zink dengan asid hidroklorik : Write balanced equation / Tulis persamaan seimbang : 2HCl + Zn ZnCl2 + H2
4
Write the formula of all the particles in the reactants and products: Tulis formula bagi semua zarah dalam bahan tindak balas dan hasil tindak balas:
2H+ + 2Cl– + Zn
Remove all the particles in the reactants and products which remain unchanged: Keluarkan semua zarah dalam bahan dan hasil tindak balas yang tidak berubah:
2H+ + 2Cl– + Zn
Ionic equation / Persamaan ion :
2H+ + Zn
Zn2+ + 2Cl– + H2
Zn2+ + 2Cl– + H2
Zn2+ + H2
Write the chemical equations and ionic equation for the following reactions: Tulis persamaan kimia dan persamaan ion untuk tindak balas berikut: Reactant / Bahan tindak balas Hydrochloric acid and #magnesium oxide Asid hidroklorik dan #magnesium oksida
Hydrochloric acid and sodium hydroxide Asid hidroklorik dan natrium hidroksida
Hydrochloric acid and magnesium Asid hidroklorik dan magnesium
Hydrochloric acid and #calcium carbonate Asid hidroklorik dan #kalsium karbonat
Sulphuric acid and zinc Asid sulfurik dan zink
Sulphuric acid and #zinc oxide Asid sulfurik dan #zink oksida
Sulphuric acid and #zinc carbonate Asid sulfurik dan #zink karbonat
Nitric acid and #copper(II) oxide Asid nitrik dan #kuprum(II) oksida
Nitric acid and sodium hydroxide Asid nitrik dan natrium hidroksida
Chemical equations / Persamaan kimia MgO + 2HCl
MgCl2 + H2O
HCl + NaOH
NaCl + H2O
2HCl + Mg 2HCl + CaCO3 H2SO4 + Zn H2SO4 + ZnO H2SO4 +ZnCO3 2HNO3 + CuO HNO3 + NaOH
MgCl2 + H2 CaCl2 + CO2 + H2O ZnSO4 + H2 ZnSO4 +H2O ZnSO4 + CO2 + H2O Cu(NO3)2 + H2O NaNO3 + H2O
Ionic equation / Persamaan ion 2H+ + MgO
Mg2+ + H2O
H+ + OH– 2H+ + Mg 2H+ + CaCO3
Mg2+ + H2 Ca2+ + CO2 + H2O
2H+ + Zn
Zn2+ + H2
2H+ + ZnO 2H+ + ZnCO3
H2O
Zn2+ + H2O Zn2+ + CO2 + H2O
2H+ + CuO H+ + OH–
Cu2+ + H2O H2O
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# Ions in magnesium oxide, calcium carbonate, zinc oxide, zinc carbonate and copper(II) oxide cannot be separated because the compounds are insoluble in water and the ions do not ionise. # Ion dalam magnesium oksida, kasium karbonat, zink oksida, zink karbonat dan kuprum(II) oksida tidak boleh diasingkan kerana sebatian tersebut tidak larut dalam air dan ion-ionnya tidak mengion.
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MODULE • Chemistry Form 4
CHEMICAL PROPERTIES OF ALKALIS / SIFAT KIMIA ALKALI
Chemical properties
Write the balance chemical equation for the reaction
Sifat-sifat kimia
1 Alkali + Acid Alkali + Asid
Salt + Water
Penyediaan garam terlarut (Tajuk Garam)
2 Alkali + Ammonium salt Alkali + Garam Ammonium
Salt + Water + Ammonia gas
*Gas ammonia dibebaskan apabila alkali dipanaskan dengan garam ammonium. Gas ammonia mempunyai bau yang sengit dan menukar kertas litmus merah lembap kepada biru. *Application of the reaction / Aplikasi tindak balas :
H2SO4 + 2KOH
K2SO4 + 2H2O
(b) Barium hydroxide and hydrochloric acid: Barium hidroksida dan asid hidroklorik:
2HCl + Ba(OH)2
BaCl2 + H2O
(c) Ammonium chloride and potassium hydroxide: Ammonium klorida dan kalium hidroksida:
Garam + Air + Gas ammonia
*Ammonia gas is released when alkali is heated with ammonium salt. Ammonia gas has pungent smell and turn moist red litmus paper to blue.
Kalium hidroksida dan asid sulfurik :
Garam + Air
*Alkali neutralises acid / Alkali meneutralkan asid. *Application of the reaction / Aplikasi tindak balas : – Preparation of soluble salt (Topic Salt)
Tuliskan persamaan kimia seimbang bagi tindak balas
(a) Potassium hydroxide and sulphuric acid
KOH + NH4Cl
KCl + H2O + NH3
(d) Ammonium sulphate and sodium hydroxide: Ammonium sulfat dan natrium hidroksida:
2NaOH + (NH4)2SO4
Na2SO4 + 2H2O + 2NH3
– Confirmatory test for cations ammonium in qualitative analysis of salt (Topic Salt)
Ujian pengesahan kation ammonium dalam analisis kualitatif garam (Tajuk Garam)
3 Alkali + Metal ion Alkali + Ion logam
Insoluble metal hydroxide
Logam hidroksida tak larut
*Most of the metal hydroxides are insoluble. *Kebanyakan logam hidroksida tak terlarut.
(e) 2OH–(aq/ak) + Mg2+(aq/ak)
Magnesium hydroxide (white precipitate) Magnesium hidroksida (mendakan putih)
*Hydroxides of transition element metals are coloured. *Hidroksida bagi logam peralihan adalah berwarna. *Application of the reaction / Aplikasi tindak balas :
– Confirmatory test for cations in qualitative analysis of salt (Topic Salt)
Mg(OH)2(p)
(f) 2OH–(aq/ak) + Cu2+(aq/ak)
Ujian pengesahan bagi kation dalam analisis kualitatif garam (Tajuk Garam)
Cu(OH)2(p) Copper(II) hydroxide (blue precipitate) Kuprum(II) hidroksida (mendakan biru)
ROLE OF WATER AND THE PROPERTIES OF ACID / PERANAN AIR DAN SIFAT ASID
An acid shows its acidic properties when it is dissolved in water.
1
Asid menunjukkan sifat keasidannya apabila terlarut dalam air.
Acid molecules ionise in aqueous solution to form hydrogen ions. The presence of hydrogen ions is needed for the acid to show its acidic properties.
2
Molekul asid mengion dalam larutan akueus membentuk ion hidrogen. Kehadiran ion hidrogen diperlukan oleh asid untuk menunjukkan sifat keasidannya.
Acid will remain in the form of molecules in two conditions / Asid akan kekal dalam bentuk molekul dengan dua keadaan: (a) Without the presence of water for example dry hydrogen chloride gas and *glacial ethanoic acid.
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Tanpa kehadiran air seperti gas hidrogen klorida kering dan *asid etanoik glasial
(b) Acid is dissolved in *organic solvent for example solution of hydrogen chloride in methylbenzene and ethanoic acid in propanone.
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Asid dilarutkan dalam *pelarut organik seperti larutan hidrogen klorida dalam metilbenzena dan asid etanoik dalam propanon. * Glacial ethanoic acid is pure ethanoic acid / Asid etanoik glasial ialah asid etanoik tulen. * Organic solvent is covalent compound that exist as liquid at room temperature such as propanone, methylbenzene and trichloromethane. * Pelarut organik ialah sebatian kovalen yang wujud dalam bentuk cecair pada suhu bilik seperti propanon, metilbenzena dan triklorometana.
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Chemistry Form 4 • MODULE
4
Example / Contoh : Glacial ethanoic acid
Solution of hydrogen chloride in methylbenzene
Asid etanoik glasial
Larutan hidrogen klorida dalam metilbenzena
HCl
CH3COOH CH3COOH
HCl
CH3COOH
HCl
CH3COOH CH3COOH
HCl
HCl
CH3COOH CH3COOH
Larutan hidrogen klorida dalam air (asid hidroklorik)
HCl
H+
H+ Cl-
HCl
• Glacial ethanoic acid molecules do not • Hydrogen chloride molecules in ionise . methylbenzene do not ionise . • Glacial ethanoic exist as molecule only, no hydrogen ions present. Etanoik glasial hanya terdiri daripada molekul CH COOH sahaja, tiada ion 3 hidrogen hadir.
ClH+
Methylbenzene / Metilbenzena
Molekul asid etanoik glasial tidak mengion .
Cl-
HCl HCl
HCl
Solution of hydrogen chloride in water (hydrochloric acid)
Molekul hidrogen klorida dalam metilbenzena tidak mengion .
ClH+
Cl-
H+
Water / Air
• Hydrogen chloride molecule in water ionises : Molekul hidrogen klorida dalam air mengion :
H+ (aq/ak) + Cl– (aq/ak) • Hydrogen chloride exist as molecule HCl (aq/ak) only, there are no hydrogen ions • Hydrogen ions and chloride ions present. present. molekul Hidrogen klorida wujud sebagai Ion
sahaja, tiada ion hidrogen hadir.
hidrogen dan
ion
klorida hadir.
• Hydrogen chloride in water • Glacial ethanoic acid and hydrogen chloride in methylbenzene does not show acidic (hydrochloric acid) shows acidic properties: properties: Asid etanoik glasial dan hidrogen klorida dalam metilbenzena tidak menunjukkan sifat asid: (i) They
do not
Sebatian tersebut
tidak
do not
turn
Sebatian tersebut
tidak
(ii) They
Hidrogen klorida dalam air (asid hidroklorik) menunjukkan sifat asid:
react with metal, base or metal carbonate. bertindak balas dengan logam, bes dan karbonat logam.
blue
litmus paper to
menukarkan warna kertas litmus
red biru
. kepada
(i) Hydrochloric acid react with metal, base or metal carbonate.
merah .
• There are no free moving ions, hydrogen chloride in methylbenzene and glacial ethanoic acid cannot conduct electricity (non-electrolyte). Tidak wujud ion bebas bergerak , asid etanoik glasial dan hidrogen klorida dalam metilbenzena tidak dapat mengkonduksikan elektrik (bukan elektrolit).
Asid hidroklorik bertindak balas dengan logam, bes dan karbonat logam.
(ii) Hydrogen ions turn blue red . litmus paper to
Ion hidrogen menukarkan warna kertas biru kepada merah . litmus
• There are free moving ions, can conduct hydrochloric acid electricity (electrolyte). Terdapat ion yang bebas bergerak , asid dapat hidroklorik mengkonduksikan elektrik (elektrolit).
ROLE OF WATER AND THE PROPERTIES OF ALKALI / PERANAN AIR DAN SIFAT ALKALI 1
In the presence of water, an alkali dissolves and ionises to produce hydroxide ions. For example potassium hydroxide solution and ammonia solution. Dengan kehadiran air, alkali melarut dan mengion menghasilkan ion hidroksida. Contohnya larutan kalium hidroksida dan larutan ammonia:
2
KOH(aq/ak ) K+(aq/ak ) + OH–(aq/ak ) NH3(g) + H2O(l/ce) NH4+(aq/ak ) + OH–(aq/ak )
Without water or in organic solvents, no hydroxide ions are produced, so the alkaline properties are not shown.
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Tanpa air atau dalam pelarut organik, tiada ion hidroksida yang dihasilkan, maka sifat-sifat alkali tidak ditunjukkan.
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MODULE • Chemistry Form 4
EXERCISE / LATIHAN
The diagram below shows the apparatus set-up to investigate the role of water and other solvent in showing the properties of acid and the observations made from the investigation.
1
Rajah di bawah menunjukkan susunan radas untuk mengkaji peranan air atau pelarut lain dalam menunjukkan sifat asid serta pemerhatian yang dibuat. Experiment / Eksperimen
I
II
Set-up of apparatus Susunan radas
Asid hidroklorik dalam air
Hydrochloric acid in tetrachloromethane
Magnesium ribbon
Magnesium ribbon
Hydrochloric acid in water
Asid hidroklorik dalam tetraklorometana
Pita magnesium
Observation
• Bubbles of gas are released
Pemerhatian
Gelembung gas dibebaskan
Pita magnesium
• No bubble of gas Tiada gelembung gas
• Magnesium ribbon dissolves Pita magnesium larut
(a) What is meant by acid / Apakah yang dimaksudkan dengan asid ? Acid is a chemical substance which ionises in water to produce hydrogen ion. (b) (i)
Name the bubble of gas released in Experiment I / Namakan gas yang terbebas dalam Eksperimen I. Hydrogen gas
(ii) Write the chemical equation for the formation of the bubbles in Experiment I. Tulis persamaan kimia untuk pembentukan gelembung gas dalam Eksperimen I.
Mg + 2HCl MgCl2 + H2
(iii) Write the ionic equation for the chemical equation in (b)(ii). Tulis persamaan ion untuk persamaan kimia dalam (b)(ii).
Mg + 2H+ Mg2+ + H2 (c) Compare observation in Experiment I and Experiment II. Explain your answer. Bandingkan pemerhatian dalam Eksperimen I dan Eksperimen II. Terangkan jawapan anda.
– Hydrochloric acid in water in Experiment I Asid hidroklorik dalam air dalam Eksperimen I
reacts
with magnesium.
bertindak balas
dengan magnesium.
– Hydrochloric acid in tetrachloromethane in Experiment I do not react with magnesium. Asid hidroklorik dalam tetraklorometana dalam Eksperimen II
– Hydrochloric acid in water – H+ ions react with
ionises
magnesium atom
tidak bertindak balas
to H+ / Asid hidroklorik dalam air HCl H+ + Cl–
dengan magnesium. mengion kepada ion H+:
to produce hydrogen molecule:
Ion H+ bertindak balas dengan atom magnesium untuk menghasilkan molekul hidrogen:
Mg + 2H+ Mg2+ + H2
– Hydrochloric acid in tetrachloromethane remains in the form of molecule . No hydrogen ion present.
m
molekul
. Tiada ion
hidrogen
hadir.
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Chemistry Form 4 • MODULE
2
The diagram below shows the set-up of apparatus to prepare two solutions of ammonia in solvent X and solvent Y. A piece of red litmus paper is dropped into each beaker. Gambar rajah di bawah menunjukkan susunan radas bagi menyediakan dua larutan ammonia dalam pelarut X dan pelarut Y. Sekeping kertas litmus merah dimasukkan ke dalam setiap bikar. Ammonia
Ammonia
Ammonia
Ammonia
Solvent X
Solvent Y
Pelarut X
Pelarut Y
Beaker A / Bikar A
Beaker B / Bikar B
The table below shows the observation on the red litmus paper in solvent X and solvent Y. Jadual di bawah menunjukkan pemerhatian ke atas kertas litmus merah dalam pelarut X dan pelarut Y. Solution / Larutan
Observation / Pemerhatian
Ammonia in solvent X in beaker A
The red litmus paper turns blue.
Ammonia dalam pelarut X dalam bikar A
Kertas litmus merah bertukar menjadi biru.
Ammonia in solvent Y in beaker B
No visible change in the colour of red litmus paper.
Ammonia dalam pelarut Y dalam bikar B
Tiada perubahan yang nyata pada warna kertas litmus merah.
(a) Name possible substances that can be solvent X and solvent Y. Namakan bahan-bahan yang mungkin bagi pelarut X dan pelarut Y.
Solvent X / Pelarut X : Water Solvent Y / Pelarut Y : Propanone / methylbenzene / trichloromethane
(b) Explain the difference in the observation on the beakers A and B. Terangkan perbezaan antara pemerhatian dalam bikar A dengan bikar B.
– Ammonia gas in beaker A is dissolved in water, ammonia molecules hydroxide ions: Gas ammonia dalam bikar A ion hidroksida :
larut
dalam air, molekul ammonia
NH3 (g) + H2O (l/ce)
ionise
mengion
to ammonium ion and
kepada ion
ammonium
dan
NH 4+ (ak) + OH– (ak)
– The presence of hydroxide ions change the red litmus paper to blue. Kehadiran ion-ion
hidroksida
menukar kertas litmus merah kepada biru.
– Ammonia gas in beaker B is dissolved in molecules do not ionise . Gas ammonia dalam bikar B mengion .
larut
propanone / methylbenzene / trichloromethane propanon / metilbenzena / triklorometana
dalam
, ammonia
, molekul ammonia tidak
– No hydroxide ions present, the red litmus paper remains unchanged. Tiada ion
(c) (i)
hidroksida
, warna merah kertas litmus tidak berubah.
Between solution in beakers A and B, which one is an electrolyte and non-electrolyte? Explain your answer. Antara larutan dalam bikar A dangan bikar B, yang manakah elektrolit dan bukan elektrolit? Terangkan jawapan anda.
an electrolyte – Solution in beaker A is , it contains ionisation of ammonia molecules in water.
free moving ions
elektrolit , ia mengandungi ion-ion yang Larutan dalam bikar A ialah pengionan molekul ammonia dalam air.
– Solution in beaker B is a non-electrolyte , ammonia molecules propanone / methylbenzene / trichloromethane . , molekul ammonia
bebas bergerak
do not ionise
tidak mengion
daripada
in
dalam
.
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bukan elektrolit Larutan dalam bikar B propanon / metilbenzena / triklorometana
from the
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MODULE • Chemistry Form 4
(ii) Draw a labelled diagram to show the set-up of apparatus used to show the electrical conductivity of an electrolyte. Lukiskan gambar rajah berlabel yang menunjukkan susunan radas yang digunakan untuk menunjukkan kekonduksian arus elektrik bagi sesuatu elektrolit.
Carbon electrode Elektrod karbon
Carbon electrode Elektrod karbon
Elektrolit Electrolyte
THE pH SCALE / SKALA pH
The pH is a scale of numbers to measure the degree of acidity and alkalinity of an aqueous solution based on the concentration of hydrogen ions, H+ or hydroxide ions, OH–.
1
Skala pH ialah skala bernombor untuk mengukur darjah keasidan dan kealkalian suatu larutan akueus berdasarkan kepekatan ion hidrogen, H+ atau ion hidroksida, OH–.
The pH scale has the range of number from 0 to 14 / Skala pH bernombor dari 0 hingga 14 :
2
pH
0
1
2
3
4
5
6
pH < 7: • Acidic solution / Larutan berasid. • The lower the pH value, the higher is the concentration of hydrogen ion, H+.
7
pH = 7 Neutral Neutral
8
9
10
11
12
13
14
pH > 7: • Alkaline solution / Larutan beralkali. • The higher the pH value, the higher is the concentration of hydroxide ion, OH–.
Semakin rendah nilai pH, semakin tinggi kepekatan ion hidrogen, H+.
Semakin tinggi nilai pH, semakin tinggi kepekatan ion hidroksida, OH–.
The pH of an aqueous solution can be measured by / Nilai pH bagi sesuatu larutan akueus boleh diukur dengan menggunakan: (a) pH meter / Meter pH (b) Acid-base indicator / Penunjuk asid-bes Complete the following table / Lengkapkan jadual berikut :
3
Colour / Warna
Indicator Penunjuk
Acid / Asid
Neutral / Neutral
Alkali / Alkali
Litmus solution / Larutan litmus
Red
Purple
Blue
Methyl orange / Metil jingga
Red
Orange
Yellow
Colourless
Colourless
Pink
Red
Green
Purple
Phenolphthalein / Fenolftalein Universal indicator / Penunjuk universal
THE STRENGTH OF ACID AND ALKALI / KEKUATAN ASID DAN ALKALI
The strength of acid and alkali depend on the degree of ionisation or dissociation of the acid and alkali in water.
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Kekuatan asid dan alkali bergantung pada darjah pengionan asid dan alkali dalam air. (a) A strong acid is an acid that ionises completely in water to produce high concentration of hydrogen ion, H+. Asid kuat ialah asid yang mengion sepenuhnya dalam air menghasilkan kepekatan ion hidrogen, H+ yang tinggi. (b) A weak acid is an acid that partially ionises in water to produce low concentration of hydrogen ion, H+. Asid lemah ialah asid yang mengion separa dalam air menghasilkan kepekatan ion hidrogen, H+ yang rendah. (c) A strong alkali is an alkali that ionises completely in water to produce high concentration of hydroxide ion, OH–. Alkali kuat ialah alkali yang mengion sepenuhnya dalam air menghasilkan kepekatan ion hidroksida, OH– yang tinggi. (d) A weak alkali is an alkali that partially ionises completely in water to produce low concentration of hydroxide ion, OH–. Alkali lemah ialah alkali yang mengion separa dalam air menghasilkan kepekatan ion hidroksida, OH– yang rendah.
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Chemistry Form 4 • MODULE
2
Example of different strength of acid and alkali / Contoh asid dan alkali dengan kekuatan yang berbeza. Acid / Alkali Asid / Alkali
Strong acid Asid kuat
Example
Ionisation equation
Contoh
Persamaan ion
Hydrochloric HCl (aq/ak ) acid, HCl H+ (aq/ak ) + Cl– (aq/ak ) Asid hidroklorik, HCl
Nitric acid, HNO3 Asid nitrik, HNO3
Sulphuric acid, H2SO4 Asid sulfurik, H2SO4
Weak acid Asid lemah
Ethanoic acid, CH3COOH Asid etanoik, CH3COOH
Carbonic acid, H2CO3 Asid karbonik, H2CO3
Strong alkali Alkali kuat
Sodium hydroxide, NaOH
HNO3(aq/ak ) H+ (aq/ak ) + NO3– (aq/ak )
H2SO4 (aq/ak ) 2H+ (aq/ak ) + SO42– (aq/ak )
Alkali lemah
Ammonia solution, NH3(aq) Larutan ammonia, NH3(ak)
All hydrogen chloride molecules that H+ and Cl– + – dissolve in water ionises completely into H dan Cl hydrogen ions and
chloride
ions.
All nitric acid ionises completely in water into hydrogen ions and nitrate ions.
H+ and NO3–
All sulphuric acid ionises completely into hydrogen ions and sulphate ions.
H+ and SO42–
H+ dan NO3–
H+ dan SO42–
Semua asid sulfurik mengion sepenuhnya dalam air kepada ion hidrogen dan ion sulfat .
CH3COOH (aq/ak )
Ethanoic acid partially ionises in water CH3COO (aq/ak ) + H (aq/ak ) into etahnoate ions and hydrogen ions. Some remain in the form of CH3COOH molecules . –
+
separa kepada ion Asid etanoik mengion etanoat dan ion hidrogen . Sebahagian lagi kekal dalam bentuk molekul CH3COOH.
H2CO3 (aq/ak ) 2H+ (aq/ak ) + CO32– (aq/ak )
2
NaOH (aq/ak )
Na (aq) + OH (aq) +
–
CH3COOH, CH3COO– and H+ CH3COOH, CH3COO– dan H+
H2CO3, H+ and Carbonic acid partially ionises in water into carbonate ions and hydrogen ion. Some CO32– + remain in the form of H CO molecules . H2CO3, H dan 3
CO32–
Sebahagian asid karbonik mengion dalam air kepada ion karbonat dan ion hidrogen. Sebahagian lagi kekal dalam bentuk molekul H2CO3.
Sodium hydroxide ionises completely in water into sodium ions and hydroxide ions.
Na+ and OH–
Potassium hydroxide ionises completely potassium ions and in water into hydroxide ions.
K+ and OH–
Na+
dan
OH–
Natrium hidroksida mengion sepenuhnya dalam air kepada ion natrium dan ion hidroksida .
KOH (aq/ak )
K+ (aq) + OH– (aq)
K+
dan
OH–
Kalium hidroksida mengion sepenuhnya dalam air kalium dan ion hidroksida . kepada ion
Ba(OH)2 (aq/ak )
Ba (aq) + 2OH (aq) 2+
–
Barium hidroksida, Ba(OH)2
Weak alkali
Zarah-zarah yang hadir
Semua asid nitrik mengion sepenuhnya dalam air kepada ion hidrogen dan ion nitrat .
Kalium hidroksida, KOH
Barium hydroxide, Ba(OH)2
Penerangan
Semua molekul hidrogen klorida melarut dalam air dan mengion sepenuhnya kepada ion hidrogen dan ion klorida .
Natrium hidroksida, NaOH
Potassium hydroxide, KOH
Particles present
Explanation
Barium hydroxide ionises completely in water into barium ions and hydroxide
Ba2+ and OH– Ba2+ dan OH–
ions.
Barium hidroksida mengion sepenuhnya dalam air kepada ion barium dan ion hidroksida .
NH3 (g)+ H2 O(l/ce) + NH4 (aq/ak ) + OH–(aq/ak )
Ammonia partially ionises in water into ammonium ions and hydroxide ions, some remain in the form of NH molecules . 3
separa dalam air kepada Ammonia mengion ion ammonium dan ion hidroksida , sebahagian lagi kekal dalam bentuk molekul NH .
NH3, NH4+ and OH– NH3, NH4+ dan OH–
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MODULE • Chemistry Form 4
CONCENTRATION OF ACID AND ALKALI / KEPEKATAN ASID DAN ALKALI
A solution is a homogeneous mixture formed when a solute is dissolved in a solvent. For example copper(II) sulphate solution is prepared by dissolving copper(II) sulphate powder (solute) in water (solvent).
1
Larutan adalah campuran homogen yang terbentuk apabila bahan larut dilarutkan dalam pelarut. Contohnya larutan kuprum(II) sulfat disediakan dengan melarutkan serbuk kuprum(II) sulfat (bahan larut) di dalam air (pelarut). 2
Concentration of a solution the quantity of solute in a given volume of solution which is usually 1 dm3 of solution. Kepekatan sesuatu larutan ialah kuantiti bahan terlarut dalam isi padu larutan yang tertentu, biasanya isi padu 1 dm3 larutan.
3
Concentration can be expressed in two ways / Kepekatan boleh diwakili dengan dua cara : (a) Mass of solute in gram per 1 dm3 solution, g dm–3/ Jisim bahan larut dalam gram bagi setiap 1 dm3 larutan, g dm–3. Concentration of solution (g dm–3) =
Mass of solute in gram (g) / Jisim bahan larut dalam gram (g)
Volume of solution (dm3) / Isi padu larutan (dm3) Kepekatan larutan (g dm–3) (b) Number of moles of solute in 1 dm3 solution, mol dm–3 / Bilangan mol bahan larut dalam 1 dm3 larutan, mol dm–3. Concentration of solution (mol dm–3) =
Number of mole of solute (mol) / Bilangan mol bahan larut (mol)
Volume of solution (dm3) / Isi padu larutan (dm3) Kepekatan larutan (mol dm–3) The concentration in mol dm–3 is called molarity or molar concentration. The unit mol dm–3 can be represented by ‘M’.
4
Kepekatan dalam mol dm–3 dipanggil sebagai kemolaran atau kepekatan molar. Unit mol dm–3 boleh diwakili dengan‘M’.
Molarity = Kemolaran
Number of mole of solute (mol) / Bilangan mol bahan larut (mol)
Number of mole of solute (mol) = Molarity × Volume (dm3)
Kepekatan dalam mol dm–3 (kemolaran)
Kemolaran × Isi padu (dm3)
n = MV Mv n = 1 000
Bilangan mol bahan terlarut
M = Concentration in mol dm–3 (molarity)
Volume of solution (dm3) / Isi padu larutan (dm3)
Bilangan mol bahan larut (mol)
n = Number of moles of solute
V = Volume of solution in dm3 Isi padu larutan dalam dm3
v = Volume of solution in cm3 Isi padu larutan dalam cm3
The concentration of a solution can be converted from mol dm to g dm and vice versa. –3
5
–3
Kepekatan larutan boleh ditukar daripada mol dm–3 kepada g dm–3 dan sebaliknya. × molar mass of the solute / jisim molar bahan terlarut
mol dm–3
g dm–3 ÷ molar mass of the solute / jisim molar bahan terlarut
The pH value of an acid or an alkali depends on the concentration of hydrogen ions or hydroxide ions:
6
Nilai pH bagi asid atau alkali bergantung pada kepekatan ion hidrogen atau ion hidroksida:
The higher the concentration of hydrogen ions in acidic solution, the lower the pH value. Semakin tinggi kepekatan ion hidrogen dalam larutan berasid, semakin rendah nilai pH.
The higher the concentration of hydroxide ions in alkaline solution, the higher the pH value. Semakin tinggi kepekatan ion hidroksida dalam larutan beralkali, semakin tinggi nilai pH.
The pH value of an acid or an alkali is depends on / Nilai pH bagi asid atau alkali bergantung pada: (a) The strength of acid or alkali / Kekuatan asid atau alkali – the degree of ionisation or dissociation of the acid and alkali in water / darjah pengionan asid atau alkali dalam air. (b) Molarity of acid or alkali / Kemolaran asid atau alkali – the concentration of acid or alkali in mol dm–3 / kepekatan bahan terlarut dalam mol dm–3. (c) Basicity of an acid / Kebesan asid – the number ionisable of hydrogen atom per molecule of an acid molecule in an aqueous solution.
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bilangan atom hidrogen per molekul asid yang terion dalam larutan akueus.
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0.1 mol dm–3 HCl
1.21
2.98
0.01 mol dm–3 HCl
I
Bandingkan kepekatan ion hidrogen dan nilai pH
Nilai pH bagi asid hidroklorik 0.1 mol dm–3 lebih rendah daripada asid hidroklorik 0.01 mol dm–3.
hydrochloric acid.
– The pH value of 0.1 mol dm–3 of hydrochloric acid is lower than 0.01 mol dm–3 of
Kepekatan ion hidrogen dalam asid hidroklorik tinggi daripada asid 0.1 mol dm–3 lebih hidroklorik 0.01 mol dm–3.
0.01 mol dm–3 of hydrochloric acid.
–3
– Concentration hydrogen ion in 0.1 mol dm of hydrochloric acid is higher than
HCl H+ + Cl– –3 0.01 mol dm–3 0.01 mol dm
Asid hidroklorik 0.01 mol dm–3 mengion kepada 0.01 mol dm–3 ion hidrogen:
– 0.01 mol dm–3 of hydrochloric acid ionises to –3 form 0.01 mol dm hydrogen ion:
HCl H+ + Cl– –3 0.1 mol dm–3 0.1 mol dm
Asid hidroklorik 0.1 mol dm–3 mengion kepada 0.1 mol dm–3 ion hidrogen:
– 0.1 mol dm–3 of hydrochloric acid ionises to –3 form 0.1 mol dm hydrogen ion:
lengkap dalam air kepada ion hidrogen.
Compare – Hydrochloric acid is a strong acid ionises concentration completely in water to hydrogen ion. of H+ and pH kuat yang Asid hidroklorik adalah asid value mengion
Bacaan pH meter
pH meter reading
Eksperimen
Experiment
0.05 mol dm–3 HCl
2.25
diprotik .
Nilai pH bagi asid sulfurik 0.05 mol dm–3 lebih rendah daripada asid hidroklorik 0.05 mol dm–3.
hydrochloric acid.
– The pH value of 0.05 mol dm–3 of sulphuric acid is lower than 0.05 mol dm–3 of
Kepekatan ion hidrogen dalam asid sulfurik 0.05 mol dm–3 adalah dua kali ganda (lebih tinggi) daripada asid hidroklorik 0.05 mol dm–3.
0.05 mol dm–3 of hydrochloric acid.
– Concentration hydrogen ion in 0.05 mol dm–3 of sulphuric acid is double of (higher than)
H+ + Cl– –3 0.05 mol dm–3 0.05 mol dm
HCl
Asid hidroklorik 0.05 mol dm–3 mengion lengkap dalam –3 air menghasilkan 0.05 mol dm ion hidrogen:
– 0.05 mol dm–3 of ionises completely in water –3 to form 0.05 mol dm hydrogen ion:
Asid hidroklorik adalah asid kuat monoprotik .
– Hydrochloric acid is a strong monoprotic acid.
H2SO4 2H+ + SO42– –3 0.05 mol dm–3 0.1 mol dm
Asid sulfurik 0.05 mol dm–3 mengion lengkap kepada 0.1 mol dm–3 ion hidrogen:
hydrogen ion:
– 0.05 mol dm-3 of sulphuric acid ionises –3 completely in water to form 0.1 mol dm
Asid sulfurik adalah asid kuat
– Sulphuric acid is a strong diprotic acid.
0.05 mol dm–3 H2SO4
1.15
II
0.1 mol dm–3 CH3COOH
3.45
kuat yang mengion
lengkap dalam
H+ + CH3COO–(aq/ak ) less than/kurang dari 0.1 mol dm–3
0.1 mol dm–3
Nilai pH bagi asid hidroklorik 0.1 mol dm–3 lebih rendah daripada asid etanoik 0.1 mol dm–3.
– The pH value of 0.1 mol dm–3 of hydrochloric acid lower than of 0.1 mol dm–3 of ethanoic acid.
Kepekatan ion hidrogen dalam asid hidroklorik 0.1 mol dm–3 lebih tinggi daripada asid etanoik 0.1 mol dm–3.
ethanoic acid.
– Concentration hydrogen ion in 0.1 mol dm–3 of hydrochloric acid is higher than of 0.1 mol dm–3 of
0.1 mol dm–3
CH3COOH(aq/ak )
Asid etanoik 0.1 mol dm–3 mengion kurang daripada ion hidrogen:
– 0.1 mol dm–3 of ethanoic acid ionises to less than 0.1 mol dm–3 hydrogen ion:
Asid etanoik adalah asid lemah mengion separa dalam air menghasilkan kepekatan ion hidrogen yang lebih rendah .
– Ethanoic acid is a weak acid ionises partially in water to produce lower concentration hydrogen ion.
HCl H+ + Cl– –3 0.1 mol dm–3 0.1 mol dm
–3 Asid hidroklorik 0.1 mol dm–3 mengion lengkap kepada 0.1 mol dm ion hidrogen:
– 0.1 mol dm–3 of hydrochloric acid ionises to form 0.1 mol dm–3 hydrogen ion:
Asid hidroklorik adalah asid air kepada ion hidrogen.
– Hydrochloric acid is a strong acid ionises completely in water to hydrogen ion.
0.1 mol dm–3 HCl
1.21
III
Rajah di bawah menunjukkan bacaan pH meter untuk pelbagai jenis dan kepekatan asid. Tujuan eksperimen adalah untuk mengkaji hubungan antara kepekatan ion hidrogen dengan nilai pH. Bandingkan kepekatan ion hidrogen dan nilai pH untuk asid-asid yang berikut. Terangkan jawapan anda.
The diagram below shows the reading of pH meter for different types and concentration of acids. The aim of the experiment is to investigate the relationship between concentration of hydrogen ions with the pH value. Compare the concentration of hydrogen ions and the pH value of the following acids. Explain your answer.
Example / Contoh:
Chemistry Form 4 • MODULE
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MODULE • Chemistry Form 4
PREPARATION OF STANDARD SOLUTION / PENYEDIAAN LARUTAN PIAWAI
Standard solution is a solution in which its concentration is accurately known.
1
Larutan piawai ialah larutan yang kepekatannya diketahui dengan tepat.
The steps taken in preparing a standard solution are:
2
Langkah-langkah yang diambil dalam menyediakan larutan piawai adalah:
(a) Calculate the mass of solute needed to give the required volume and molarity. Hitung jisim bahan larut yang diperlukan untuk menghasilkan isi padu dan kemolaran yang dikehendaki.
(b) The solute is weighed / Bahan larut ditimbang. (c) The solute is completely dissolved in distilled water and then transferred to a volumetric flask partially filled with distilled water. Bahan larut dilarutkan sepenuhnya dalam air suling dan dipindahkan kepada kelalang volumetrik yang sebahagiannya sudah diisi dengan air suling.
(d) Distilled water is added to the calibration mark of the volumetric flask and the flask is inverted to make sure thorough mixing. Air suling ditambah ke dalam kelalang volumetrik hingga tanda senggatan dan kelalang volumetrik ditelangkupkan beberapa kali untuk memastikan campuran sekata.
PREPARATION OF A SOLUTION BY DILUTION / PENYEDIAAN LARUTAN SECARA PENCAIRAN
Adding water to the standard solution lowered the concentration of the solution. Since no solute is added, the amount of solute in the solution before and after dilution remains unchanged: Penambahan air kepada larutan piawai merendahkan kepekatan larutan tersebut. Oleh kerana tiada bahan terlarut yang ditambah, kandungan bahan terlarut dalam larutan sebelum dan selepas pencairan tidak berubah:
Number of mol of solute before dilution = Number of mole of solute after dilution Bilangan mol bahan terlarut sebelum pencairan
M1V1
1 000
Therefore / Oleh itu,
Bilangan mol bahan terlarut selepas pencairan
=
M2V2 1 000
M1V1 = M2V2
M1 = Initial concentration of the solute / Kemolaran larutan awal V1 = Initial volume of the solution in cm3 / Isipadu larutan awal dalam cm3 M2 = Final concentration of the solute / Kemolaran larutan akhir V2 = Final volume of the solution in cm3 / Isipadu larutan akhir dalam cm3 Example / Contoh :
(a) What is meant by a standard solution / Apakah yang dimaksudkan dengan larutan piawai ?
1
Standard solution is a solution in which its concentration is accurately known. (b) (i)
You are given solid sodium hydroxide. Describe the procedure to prepare 500 cm3 of 1.0 mol dm–3 sodium hydroxide solution. [Relative atomic mass: H = 1; O = 16; Na = 23] Anda diberi pepejal natrium hidroksida. Huraikan kaedah untuk menyediakan 500 cm3 larutan natrium hidroksida 1.0 mol dm–3. [Jisim atom relatif: H = 1, O = 16, Na = 23]
Calculate the mass of sodium hydroxide / Hitung jisim natrium hidroksida :
– Molar mass of NaOH / Jisim molar NaOH = 23 + 16 + 1 = 40 g mol – Mol NaOH / Bilangan mol NaOH = 500 × 1.0/1 000 = 0.5 mol
–1
– Mass of NaOH / Jisim NaOH = mol / Bilangan mol × molar mass / Jisim molar –1 = 0.5 mol × 40 g mol = 20.0 g
Preparation of 500 cm3 1.0 mol dm–3 sodium hydroxide: Penyediaan 500 cm3 larutan natrium hidroksida 1.0 mol dm–3: Timbang
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20.0 g
of NaOH accurately using a weighing bottle .
NaOH dengan tepat menggunakan
botol penimbang
.
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Chemistry Form 4 • MODULE
20.0 g
– Dissolve
20.0 g
Larutkan
distilled water
of NaOH in
air suling
NaOH dalam
in a beaker.
di dalam bikar.
– Transfer the content into a 500 cm volumetric flask . 3
Pindahkan kandungan ke dalam kelalang volumetrik 500 cm3.
– –
Rinse
the beaker with distilled water and transfer all the contents into the volumetric flask .
Bilas
bikar dengan
Distilled water
air suling
dan pindahkan semua kandungan ke dalam kelalang volumetrik .
is added to the volumetric flask until the calibration mark .
Air suling ditambah kepada kelalang volumetrik hingga
– The volumetric flask is closed tightly with homogeneous solution. Kelalang volumetrik ditutup dengan
penutup
tanda senggatan
stopper dan
and
.
inverted
ditelangkupkan
a few times to get
beberapa kali untuk mendapatkan larutan
yang homogen.
(ii) Describe how you would prepare 250 cm3 of 0.1 mol dm–3 sodium hydroxide from the above solution. Huraikan bagaimana anda menyediakan 250 cm3 larutan natrium hidroksida 0.1 mol dm–3 daripada larutan di atas.
Calculate the volume of 1 mol dm–3 sodium hydroxide used: Hitung isi padu natrium hidroksida 1 mol dm–3 yang digunakan:
– M1 × V1 = M2 × V2 – V1 =
M2 × V2 = 0.1 × 250 = 25 cm3 M1 1
Preparation of 250 cm3 1.0 mol dm–3 sodium hydroxide solution: Penyediaan 250 cm3 larutan natrium hidroksida 1.0 mol dm–3:
– A pipette is filled with
25 cm3
of 1.0 mol dm–3 sodium hydroxide solution.
Sebuah pipet diisi dengan
25 cm3
larutan natrium hidroksida 1.0 mol dm–3.
– –
25 cm3
of 1.0 mol dm–3 NaOH is transferred into 250 cm3 volumetric flask .
25 cm3
NaOH 1.0 mol dm–3 dipindahkan kepada kelalang volumetrik 250 cm3.
Distilled water
is added to the volumetric flask until the calibration mark .
Air suling ditambah kepada kelalang volumetrik hingga
– The volumetric flask is closed tightly with homogeneous solution. Kelalang volumetrik ditutup dengan
penutup
tanda senggatan
stopper dan
and
ditelangkupkan
.
inverted
a few times to get
beberapa kali untuk mendapatkan larutan
yang homogen.
EXERCISE / LATIHAN 1
The table below shows the pH value of a few substances / Jadual di bawah menunjukkan nilai pH bagi beberapa bahan. Substance / Bahan
pH value / Nilai pH
Ethanoic acid 0.1 mol dm / Asid etanoik 0.1 mol dm
3
Hydrochloric acid 0.1 mol dm–3 / Asid hidroklorik 0.1 mol dm–3
1
Glacial ethanoic acid / Asid etanoik glasial
7
–3
–3
(a) (i)
What is meant by weak acid and strong acid / Apakah yang dimaksudkan dengan asid lemah dan asid kuat ?
Weak acid / Asid lemah : An acid that partially ionises in water to produce low concentration of hydrogen ion, + H .
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Strong acid / Asid kuat : An acid that completely ionises in water to produce high concentration of hydrogen + ion, H .
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MODULE • Chemistry Form 4
(ii) Between ethanoic acid and hydrochloric acid, which acid has the higher concentration of H+ ion? Explain your answer. Antara asid etanoik dengan asid hidroklorik, asid manakah mempunyai kepekatan ion H+ yang lebih tinggi? Terangkan jawapan anda.
higher
– Hydrochloric acid has
concentration of H+ than ethanoic acid. tinggi
Asid hidroklorik mempunyai kepekatan ion H+ yang lebih
berbanding dengan asid etanoik.
– Hydrochloric acid is a strong acid which ionises completely in water to produce concentration of H+: asid kuat
Asid hidroklorik ialah tinggi yang lebih
HCl (aq/ak )
:
sepenuhnya
yang mengion
lemah
:
CH3COOH (aq/ak )
dalam air untuk menghasilkan kepekatan ion H+
H+(aq/ak ) + Cl–(aq/ak )
– Ethanoic acid is a weak acid which ionises H+: Asid etanoik ialah asid rendah yang lebih
higher
partially
in water to produce lower concentration of
separa
yang mengion
dalam air untuk menghasilkan kepekatan ion H+
CH3COO– (aq/ak ) + H+ (aq/ak )
(iii) Why do ethanoic acid and hydrochloric acid have different pH value? Mengapakah asid etanoik dan asid hidroklorik mempunyai nilai pH yang berbeza?
– The concentration H+ in hydrochloric acid is tinggi
Kepekatan H dalam asid hidroklorik +
– The concentration H in ehanoic acid is +
Kepekatan H dalam asid etanoik +
rendah
higher
, the pH value is rendah
, nilai pH lebih
lower
, nilai pH lebih
.
.
, the pH value is tinggi
lower
higher
.
.
(b) Glacial ethanoic acid has a pH value of 7 but a solution of ethanoic acid has a pH value less than 7. Explain the observation. Asid etanoik glasial mempunyai nilai pH 7 tetapi asid etanoik mempunyai nilai pH yang kurang daripada 7. Terangkan pemerhatian tersebut.
– Glacial ethanoic acid molecules do not ionise . Glacial ethanoic acid consists of only CH3COOH molecules . The CH COOH molecules are neutral . No hydrogen ions present. The pH value of 3 glacial ethanoic acid is 7. mengion . Asid etanoik glasial hanya terdiri daripada molekul CH3COOH Molekul asid etanoik glasial tidak Molekul hidrogen CH COOH adalah neutral. Tiada ion hadir. Nilai pH asid etanoik glasial adalah 7. sahaja. 3
– Ethanoic acid ionises partially in water to produce ethanoate ions and hydrogen ions causes the solution to have acidic property. The pH value of the solution is less than 7. etanoat hidrogen dan ion Asid etanoik mengion separa dalam air untuk menghasilkan ion asid . Nilai pH bagi larutan tersebut adalah kurang daripada 7. larutan mempunyai sifat
yang menyebabkan
The table shows the pH value of a few solution / Jadual berikut menunjukkan nilai pH bagi beberapa jenis larutan berbeza.
2
Solution / Larutan
P
Q
R
S
T
U
pH
1
3
5
7
11
14
(a) (i)
Which solution has the highest concentration of hydrogen ion? Larutan manakah yang mempunyai kepekatan ion hidrogen yang paling tinggi?
Solution P
(ii) Which solution has the highest concentration of hydroxide ion? Larutan yang manakah mempunyai kepekatan ion hidroksida yang paling tinggi?
Solution U
m
0.01 mol dm–3 of hydrochloric acid / 0.01 mol dm–3 asid hidroklorik ?
Q
(i)
(ii) 0.01 mol dm–3 of ethanoic acid / 0.01 mol dm–3 asid etanoik ?
R
(iii) 0.1 mol dm–3 ammonia aqueous / 0.1 mol dm–3 larutan ammonia ?
T
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(b) Which is the following solution could be / Larutan manakah yang mungkin
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Chemistry Form 4 • MODULE
(iv) 1 mol dm–3 of hydrochloric acid / 1 mol dm–3 asid hidroklorik ?
P
(v) 1 mol dm–3 sodium hydroxide solution / 1 mol dm–3 larutan natrium hidroksida ?
U
(vi) 1 mol dm–3 potassium sulphate solution / 1 mol dm–3 larutan kalium sulfat ?
S
(c) (i)
State two solutions which react to form neutral solution. Nyatakan dua larutan yang bertindak balas untuk membentuk larutan neutral.
P/Q/R and T/U // Hydrochloric acid/ethanoic acid with ammonia aqueous/sodium hydroxide solution.
(ii) Which solutions will produce carbon dioxide gas when calcium carbonate powder is added? Larutan manakah menghasilkan gas karbon dioksida apabila ditambah serbuk kalsium karbonat?
P/Q // Hydrochloric acid/ethanoic acid 3
The molarity of sodium hydroxide solution is 2 mol dm–3. What is the concentration of the solution in g dm–3? [RAM: Na = 23, 0 = 16, H = 1] Kemolaran larutan natrium hidroksida ialah 2 mol dm–3. Apakah kepekatan larutan tersebut dalam g dm–3? [JAR: Na = 23, O = 16, H = 1]
Answer / Jawapan : 4
80 g dm–3
Calculate the molarity of the solution obtained when 14 g potassium hydroxide is dissolved in distilled water to make up 500 cm3 solution. [RAM: K = 39, H = 1, O = 16] Hitung kemolaran larutan yang diperoleh apabila 14 g kalium hidroksida dilarutkan dalam air suling untuk menyediakan larutan yang berisi padu 500 cm3. [JAR: K = 39, H = 1, O = 16]
Answer / Jawapan : 5
0.5 mol dm–3
Calculate the molarity of a solution which is prepared by dissolving 0.5 mol of hydrogen chloride, HCl in distilled water to make up 250 cm3 solution. Hitung kemolaran larutan yang disediakan dengan melarutkan 0.5 mol hidrogen klorida, HCl dalam air suling untuk menyediakan larutan yang berisi padu 250 cm3.
Answer / Jawapan : 6
2 mol dm–3
How much of sodium hydroxide in gram should be dissolved in water to prepare 500 cm3 of 0.5 mol dm–3 sodium hydroxide solution? [RAM: Na = 23, O = 16, H = 1] Berapakah jisim natrium hidroksida dalam gram yang patut dilarutkan dalam air untuk menyediakan 500 cm3 larutan natrium hidroksida 0.5 mol dm–3? [JAR: Na = 23, O = 16, H = 1]
10 g
Answer / Jawapan : 7
300 cm3 water is added to 200 cm3 hydrochloric acid, 1 mol dm–3. What is the resulting molarity of the solution? Jika 300 cm3 air ditambah kepada 200 cm3 asid hidroklorik 1 mol dm–3, apakah kemolaran bagi larutan yang dihasilkan?
0.4 mol dm–3
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Answer / Jawapan :
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MODULE • Chemistry Form 4
Calculate the volume of nitric acid, 1 mol dm–3 needed to be diluted by distilled water to obtain 500 cm3 of nitric acid, 0.1 mol dm–3.
8
Hitung isi padu asid nitrik 1 mol dm–3 yang diperlukan untuk dilarutkan oleh air suling bagi menghasilkan 500 cm3 asid nitrik 0.1 mol dm–3.
Answer / Jawapan :
50 cm3
(a) Compare the number of mol of H+ ions which are present in 50 cm3 of 1 mol dm–3 of sulphuric acid and 50 cm3 of 1 mol dm–3 of hydrochloric acid. Explain your answer.
9
Bandingkan bilangan mol ion H+ yang hadir dalam 50 cm3 asid sulfurik 1 mol dm–3 dengan 50 cm3 asid hidroklorik 1 mol dm–3. Terangkan jawapan anda. Acid Asid
50 cm3 of 1 mol dm–3 of sulphuric acid 50 cm3 asid sulfurik 1 mol dm–3
50 × 1 Calculate number of Number of mol of sulphuric acid = 1 000 hydrogen ion, H+ Hitung bilangan mol = 0.05 mol + ion hidrogen, H
H2SO4
2H + SO4 +
50 cm3 of 1 mol dm–3 of hydrochloric acid 50 cm3 asid hidroklorik 1 mol dm–3
HCl
2–
From the equation,
50 × 1 1 000 = 0.05 mol
Number of mol of hydrochloric acid =
H+ + Cl–
From the equation,
1 mol of H2SO4 : 2 mol of H
1 mol of HCl : 1 mol of H+
0.05 mol of H2SO4 : 0.1 mol of H+
0.05 mol of HCl : 0.05 mol of H+
+
Compare the number The number of H+ in 50 cm3 of 1 mol dm–3 of sulphuric acid is twice of the number of H+ in of hydrogen ions 50 cm3 of 1 mol dm–3 of hydrochloric acid. Bandingkan bilangan ion hidrogen
Explanation Penerangan
Sulphuric acid is diprotic acid whereas hydrochloric acid is monoprotic acid. 1 mol of sulphuric ionises to 2 mol of H+ whereas 1 mol of hydrochloric acid ionises to 1 mol of H+. The number of H+ in the same volume and concentration of both acids is doubled in sulphuric acid compared to hydrochloric acid.
(b) Suggest the volume of 1 mol dm–3 of hydrochloric acid that has the same number of H+ with 50 cm3 of 1 mol dm–3 of sulphuric acid. Cadangkan isi padu asid hidroklorik 1 mol dm–3 yang mempunyai bilangan ion H+ yang sama dengan 50 cm3 asid sulfurik 1 mol dm–3.
100 cm3
NEUTRALISATION / PENEUTRALAN Neutralisation is the reaction between an acid and a base to form only salt and water: Peneutralan ialah tindak balas antara asid dan bes untuk membentuk garam dan air sahaja:
1
Acid / Asid + Base / Bes
Salt / Garam + Water / Air
Example / Contoh : HCl (aq/ak ) + NaOH (aq/ak ) 2HNO3 (aq/ak ) + MgO (s/p)
NaCl (aq/ak ) + H2O (l/ce) Mg(NO3)2 (aq/ak ) + H2O (l/ce)
In neutralisation, the acidity of an acid is neutralised by an alkali. At the same time the alkalinity of an alkali is neutralised by an acid. The hydrogen ions in the acid react with hydroxide ions in the alkali to produce water:
2
Dalam peneutralan, keasidan asid dineutralkan oleh alkali. Pada masa yang sama, kealkalian alkali dineutralkan oleh asid. Ion hidrogen dalam asid bertindak balas dengan ion hidroksida dalam alkali:
H+ (aq/ak ) + OH– (aq/ak )
m
H2O (l/ce)
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Chemistry Form 4 • MODULE
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Application of neutralisation in daily life / Aplikasi peneutralan dalam kehidupan seharian : Application
Example
Aplikasi
Agriculture Agrikultur
Contoh
1 Acidic soil is treated with powdered CaCO3)or ashes of burnt wood.
soda lime
(calcium oxide, CaO),
limestone
(calcium carbonate,
Tanah berasid dirawat dengan serbuk kapur tohor (kalsium oksida, CaO), batu kapur (kalsium karbonat, CaCO3) atau abu daripada kayu api.
2 Basic soil is treated with compost. The alkalis in basic soil. Tanah berbes dirawat dengan kompos. Gas dalam tanah berbes.
acidic berasid
gas from the decomposition of compost neutralises the yang terbebas daripada penguraian kompos
3 The acidity of water farming is controlled by adding
soda lime
meneutralkan
alkali
, (calcium oxide, CaO).
Keasidan air dalam pertanian dikawal dengan menambah kapur tohor (kalsium oksida, CaO).
Industries Industri
soda lime
1 Acidic gases emitted by industries are neutralised with are released into air.
, (calcium oxide, CaO) before the gases
Gas-gas berasid yang dibebaskan oleh kilang dineutralkan dengan kapur tohor (kalsium oksida, CaO), sebelum gas-gas tersebut dibebaskan ke udara.
2 Organic acid produced by bacteria in latex neutralises by
ammonia
and prevents coagulation.
Ammonia meneutralkan asid organik yang dihasilkan oleh bakteria dalam lateks dan mencegah penggumpalan.
Health Kesihatan
1 Excess acid in the stomach is neutralised with its anti-acids that contain bases such as aluminium hydroxide , calcium carbonate and magnesium hydroxide . Anti-asid mengandungi bes seperti aluminium hidroksida , meneutralkan asid berlebihan dalam perut.
2 Toothpastes contain mouth. Ubat gigi mengandungi mulut.
3
magnesium hidroksida
untuk
(such as magnesium hydroxide) to neutralise the acid produced by bacteria in (seperti magnesium hidroksida) untuk meneutralkan asid yang dihasilkan oleh bakteria dalam
(natrium hidrogen karbonat) digunakan untuk merawat sengatan lebah yang beralkali.
Vinegar (Ethanoic acid) is used to cure acidic wasp sting. Cuka
4
bes
dan
Baking powder (sodium hydrogen carbonate) is used to cure alkaline bee stings. Serbuk penaik
4
bases
kalsium karbonat
(asid etanoik) digunakan untuk merawat sengatan tebuan yang berasid.
An acid-base titration / Pentitratan asid-bes : (a) It is a technique used to determine the volume of an acid required to neutralise a fixed volume of an alkali with the help of acid-base indicator. Ianya adalah teknik yang digunakan untuk menentukan isi padu asid yang diperlukan untuk meneutralkan isi padu tertentu alkali dengan bantuan penunjuk asid-bes. Penunjuk yang biasa digunakan adalah fenolftalein dan metil jingga. (b) Steps taken are / Langkah-langkah yang diambil adalah :
(i)
An exact volume of alkali is measured with a pipette and poured into a conical flask.
Isi padu alkali yang tepat diukur dengan pipet dan dituang ke dalam kelalang kon. (ii) A few drops of indicator are added to the alkali / Beberapa titik penunjuk ditambah kepada alkali.
(iii) A burette is filled with an acid. An acid is added drop by drop into the alkali in the conical flask until the indicator changes colour, indicating the pH of neutral solution produced.
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Buret diisi dengan asid. Asid ditambah setitik demi setitik kepada alkali dalam kelalang kon sehingga warna penunjuk bertukar, menunjukkan pH larutan neutral telah dihasilkan. (c) When the acid has completely neutralised the given volume of an alkali, the titration has reached the end point. Apabila asid sudah lengkap meneutralkan isi padu alkali yang diberi, pentitratan telah mencapai takat akhir. (d) The end point is the point in the titration at which the indicator changes colour. Takat akhir ialah takat dalam pentitratan di mana penunjuk bertukar warna. (e) The commonly used indicators are phenolphthalein and methyl orange. Penunjuk yang biasa digunakan adalah fenolftalein dan metil jingga.
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MODULE • Chemistry Form 4
The general steps used in any calculation involving neutralisation:
5
Langkah umum dalam penghitungan yang melibatkan peneutralan:
Step / Langkah 1 : Write the balanced equation / Tulis persamaan yang seimbang. Step / Langkah 2 : Write the information from the question above the equation. Tulis maklumat daripada soalan di atas persamaan.
Step / Langkah 3 : Write the information from the chemical equation below the equation (number of moles of substance involved). Tulis maklumat daripada persamaan kimia di bawah persamaan (bilangan mol bahan yang terlibat).
Step / Langkah 4 : Change the information to mole / Tukar maklumat kepada mol. Step / Langkah 5 : Use the relationship between the number of moles of the substances in Step 3. Guna hubungan di antara bilangan mol bahan-bahan dalam Langkah 3.
Step / Langkah 6 : Convert the number of mol to the required unit with the formula: Tukar bilangan mol kepada unit yang diperlukan dengan menggunakan formula:
n =
Mv 1 000
atau n = MV
n = Number of moles of solute / Bilangan mol bahan terlarut M = Concentration in mol dm–3 (molarity) / Kepekatan dalam mol dm–3 (kemolaran) V = Volume of solution in dm3 / Isi padu larutan dalam dm3 v = Volume of solution in cm3 / Isi padu larutan dalam cm3
EXERCISE / LATIHAN
50 cm3 of 1 mol dm–3 sodium hydroxide solution is neutralised by 25 cm3 of sulphuric acid. Calculate the concentration of sulphuric acid in mol dm–3 and g dm–3. [RAM: H = 1, S = 32, O = 16]
1
50 cm3 larutan natrium hidroksida 1 mol dm–3 dineutralkan oleh 25 cm3 asid sulfurik. Hitung kepekatan asid sulfurik dalam mol dm–3 dan g dm–3. [JAR: H = 1, S = 32, O = 16]
M = 1 mol dm–3 V = 50 cm3 2NaOH + H2SO4
M = ? V = 25 cm3 Na2SO4 + 2H2O
Number of mol of NaOH = 1 ×
n mol V dm3 0.025 mol = = 1 mol dm–3 25 dm3 1 000
Concentration of H2SO4 =
50 = 0.05 mol 1 000
From the equation, 2 mol of NaOH : 1 mol of H2SO4 0.05 mol of NaOH : 0.025 mol of H2SO4
Concentration of H2SO4 = 1 mol dm–3 × (2 × 1 + 32 + 16 × 4) g mol–1 = 98 g dm–3
Calculate the volume of 2 mol dm–3 sodium hydroxide needed to neutralise 100 cm3 of 1 mol dm–3 hydrochloric acid.
2
Hitung isi padu larutan natrium hidroksida 2 mol dm–3 yang diperlukan untuk meneutralkan 100 cm3 asid hidroklorik 1 mol dm–3.
M = 2 mol dm–3 V = ? cm3
M = 1 mol dm–3 V = 100 cm3
NaOH +
HCl
Number of mol of HCl = 1 ×
NaCl + H2O
100 = 0.1 mol 1 000
1 mol of HCl : 1 mol of mol NaOH 0.1 mol of HCl : 0.1 mol of mol NaOH n mol Volume of NaOH = M mol dm–3 0.1 mol = 2 mol dm–3 –3 = 0.05 dm = 50 cm3 m
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From the equation,
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Chemistry Form 4 • MODULE
3
Experiment I / Eksperimen I 1 mol dm–3 of nitric acid is used to neutralise 100 cm3 of 1 mol dm–3 sodium hydroxide solution. Asid nitrik 1 mol dm–3 digunakan untuk meneutralkan 100 cm3 larutan natrium hidroksida 1 mol dm–3.
Experiment II / Eksperimen II 1 mol dm–3 of sulphuric acid is used to neutralise 100 cm3 of 1 mol dm–3 sodium hydroxide solution. Asid sulfurik 1 mol dm–3 digunakan untuk meneutralkan 100 cm3 larutan natrium hidroksida 1 mol dm–3.
Compare the volume of acids needed to neutralise 100 cm3 of 1 mol dm–3 sodium hydroxide solution in Experiment I and Experiment II. Explain your answer. Bandingkan isi padu asid yang diperlukan untuk meneutralkan 100 cm3 larutan natrium hidroksida 1 mol dm–3 dalam Eksperimen I dan Eksperimen II. Terangkan jawapan anda. Answer / Jawapan: Experiment Eksperimen
Balanced equation Persamaan kimia
Calculation Pengiraan
Experiment I
Experiment II
Eksperimen I
NaOH + HNO3
Eksperimen II
NaNO3 + H2O
2NaOH + H2SO4
Na2SO4 + 2H2O
100 1 000 = 0.1 mol From the equation / Daripada persamaan : 1 mol NaOH : 1 mol HNO
100 1 000 = 0.1 mol From the equation / Daripada persamaan : 2 mol NaOH / NaOH : 1 mol H SO
0.1 mol NaOH : 0.1 mol HNO 3 Mv Mol of HCl / Bilangan mol HNO3 = 1 000 M = Concentration of HNO3 / Kepekatan HNO3 v = Volume of HNO3 in cm3 / Isi padu HNO3 dalam cm3 1 mol dm–3 × v = 0.1 mol 1 000 3 v = 100 cm
0.1 mol NaOH / NaOH : 0.05 mol H SO 2 4 Mv Mol of H2SO4 / Bilangan mol H2SO4 = 1 000 M = Concentration of H2SO4 / Kepekatan H2SO4 v = Volume of H2SO4 in cm3 / Isi padu H2SO4 dalam cm3 1 mol dm–3 × v = 0.1 mol 1 000 3 v = 50 cm
Mol of KOH / Bilangan mol NaOH = 1 ×
Mol of KOH / Bilangan mol NaOH = 1 ×
3
2
Comparison and explanation
– The volume of acid needed in Experiment II is doubled of Experiment I.
Perbandingan dan penerangan
– Sulphuric acid is
4
Isi padu asid nitrik yang diperlukan adalah dua kali ganda dalam Eksperimen I dibandingkan dengan Eksperimen II.
diprotic
Asid sulfurik adalah asid
acid while nitric acid is monoprotic .
diprotik
– One mol of sulphuric ionises
manakala asid nitrik adalah asid
two
Satu mol asid sulfurik mengion kepada ion H+.
monoprotik
.
mol of H , one mol nitric acid ionises to
dua
+
one
mol of H+.
mol ion H manakala satu mol asid nitrik mengion kepada +
satu
mol
– The number of H+ in the same volume and concentration of both acids is doubled in sulphuric acid compared to hydrochloric acid. Bilangan ion H+ dalam isi padu dan kepekatan yang sama bagi kedua-dua asid adalah dua kali ganda dalam asid sulfurik dibandingkan dengan asid nitrik.
4
Diagram below shows the apparatus set-up for the titration of potassium hydroxide solution with sulphuric acid. Gambar rajah di bawah menunjukkan susunan radas bagi pentitratan larutan kalium hidroksida dengan asid sulfurik.
0.5 mol dm–3 sulphuric acid Asid sulfurik 0.5 mol dm–3
50 cm3 of 1 mol dm3 potassium hydroxide solution + methyl orange 50 cm3 larutan kalium hidroksida 1 mol dm3 + metil jingga
0.5 mol dm–3 sulphuric acid is titrated to 50 cm3 of 1 mol dm3 potassium hydroxide solution and methyl orange is used as indicator.
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Asid sulfurik 0.5 mol dm–3 ditambahkan kepada 50 cm3 larutan kalium hidroksida 1 mol dm3 dan metil jingga digunakan sebagai penunjuk.
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MODULE • Chemistry Form 4
(a) (i)
Name the reaction between sulphuric acid and potassium hydroxide. Namakan tindak balas antara asid sulfurik dengan kalium hidroksida.
Neutralisation
(ii) Name the salt formed in the reaction / Namakan garam yang terbentuk dalam tindak balas tersebut. Potassium sulphate
(b) Suggest an apparatus that can be used to measure 25.0 cm3 of potassium hydroxide solution accurately. Cadangkan radas yang boleh digunakan untuk mengukur 25.0 cm3 larutan kalum hidroksida dengan tepat.
Pipette (c) What is the colour of methyl orange / Apakah warna metil jingga dalam (i) in potassium hydroxide solution / larutan kalium hidroksida? Red (ii) in sulphuric acid / asid sulfurik? Yellow (iii) at the end point of the titration / pada titik akhir pentitratan? Orange (d) (i) Write a balanced equation for the reaction that occurs / Tuliskan persamaan seimbang bagi tindak balas yang berlaku. 2KOH + H2SO4
K2SO4 + 2H2O
(ii) Calculate the volume of the 0.1 mol dm–3 sulphuric acid needed to completely react with 50 cm3 of 1 mol dm3 potassium hydroxide. Hitung isi padu asid sulfurik 0.1 mol dm–3 yang diperlukan untuk bertindak balas dengan lengkap dengan 50 cm3 larutan kalium hidroksida 1 mol dm–3.
Number of mol KOH = 1 × From the equation,
50 = 0.05 mol 1 000
2 mol of KOH : 1 mol of H2SO4 0.05 mol of KOH : 0.025 mol of H2SO4
n mol M mol dm–3 0.025 mol = 1 mol dm–3 = 0.025 dm3 = 25 cm3
Volume of H2SO4 =
(e) (i)
The experiment is repeated with 0.1 mol dm hydrochloric acid to replace sulphuric acid. Predict the volume of hydrochloric acid needed to neutralise 50.0 cm3 potassium hydroxide solution. –3
Eksperimen diulang dengan menggunakan asid hidroklorik 0.1 mol dm–3 untuk menggantikan asid sulfurik. Ramalkan isipadu asid hidroklorik yang diperlukan untuk meneutralkan 50.0 cm3 larutan kalium hidroksida.
50 cm3 // double the volume of sulphuric acid
(ii) Explain your answer in (e)(i) / Terangkan jawapan anda di (e)(i). – Hydrochloric acid is a monoprotic acid whereas sulphuric acid is a Asid hidroklorik ialah asid
monoprotik
manakala asid sulfurik ialah asid
diprotic diprotik
– The same volume and concentration of both acids, hydrochloric acid contains of mole of H+ ions as in sulphuric acid.
m
half separuh
the number bilangan
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Pada isi padu dan kepekatan yang sama untuk kedua-dua asid, asid hidroklorik mengandungi mol ion H+ daripada asid sulfurik.
acid. .
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Chemistry Form 4 • MODULE
Objective Questions / Soalan objektif 1
Which of the following substances changes blue litmus paper to red when dissolved in water?
5
The table below shows the concentration of hydrochloric acid and ethanoic acid. Jadual di bawah menunjukkan kepekatan asid hidroklorik dan asid etanoik.
Antara bahan berikut, yang manakah menukarkan warna kertas litmus merah kepada biru apabila dilarutkan dalam air?
A Sulphur dioxide
Acid
Sulfur dioksida B
Carbon dioxide Lithium oxide
Ethanoic acid
Sodium carbonate
Which of the following statements is true about both acids?
The table below shows the pH value of four acids which have the same concentration.
Antara berikut, yang manakah adalah betul tentang kedua-dua asid?
Jadual di bawah menunjukkan nilai pH empat larutan yang mempunyai kepekatan yang sama.
A Both are strong acids Kedua-duanya adalah asid kuat
Solution / Larutan
pH value / Nilai pH
B
Both acids are strong electrolyte
P
2
Q
7
C
The pH value of both acid are equal
R
12
S
13
Which of the following solutions has the highest concentration of hydroxide ion? Antara larutan berikut, yang manakah mempunyai kepekatan ion hidroksida paling tinggi?
A P B Q 3
A Sulphuric acid and copper(II) sulphate solution
6
A 20 B 40 7
Nitric acid and magnesium oxide Hydrochloric acid and sodium nitrate solution Asid hidroklorik dan larutan natrium nitrat Asid etanoik dan larutan natrium sulfat
Antara tindak balas berikut, yang manakah tidak akan membebaskan sebarang gas?
A Copper metal with sulphuric acid Logam kuprum dengan asid sulfurik
B
Zinc metal with hydrochloride acid Logam zink dengan asid hidroklorik
C
Ammonium chloride with calcium hydroxide Ammonium klorida dengan kalsium hidroksida
D Sodium carbonate hydrochloric acid
8
C 200 cm3 D 250 cm3
Which of the following solutions have the same concentration of hydrogen ions, H+, as in 0.1 mol dm–3 sulphuric acid, H2SO4? Antara asid berikut, yang manakah mempunyai kepekatan ion hidrogen, H+ yang sama dengan asid sulfurik 0.1 mol dm–3?
A 0.1 mol dm–3 hydrochloric acid Asid hidroklorik 0.1 mol dm–3
B
0.1 mol dm–3 carbonic acid Asid karbonik 0.1 mol dm–3
C
0.2 mol dm–3 ethanoic acid Asid etanoik 0.2 mol dm–3
D 0.2 mol dm–3 nitric acid Asid nitrik 0.2 mol dm–3
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Natrium karbonat dengan asid hidroklorik
What is the volume of 2.0 mol dm–3 potassium hydroxide solution needed to prepare 500 cm3 of 0.1 mol dm–3 potassium hydroxide solution?
A 100 cm3 B 150 cm3
D Ethanoic acid and sodium sulphate solution Which of the following reactions will not produce any gas?
C 80 D 120
Berapakah isi padu larutan kalium hidroksida 2.0 mol dm–3 diperlukan untuk menyediakan 500 cm3 larutan kalium hidroksida 1 mol dm–3?
Asid nitrik dan magnesium oksida
4
The molarity of sodium hydroxide solution 0.5 mol dm–3. What is the concentration of the solution in g dm–3? [Relative atomic mass: H = 1, O =16, Na = 23] Kemolaran larutan natrium hidroksida adalah 0.5 mol dm–3. Apakah kepekatan larutan itu dalam g dm–3? [Jisim atom relatif: H = 1, O =16, Na = 23]
Asid sulfurik dan larutan kuprum(II) sulfat
C
Nilai pH kedua-dua asid adalah sama
50 cm3 setiap asid memerlukan 50 cm3 larutan natrium hidroksida 0.1 mol dm–3 untuk dineutralkan
C R D S
Antara pasangan bahan tindak balas berikut, yang manakah akan menghasilkan tindak balas?
Kedua-duanya adalah elektrolit yang kuat
D 50 cm3 of each acid need 50 cm3 of 0.1 mol dm–3 of sodium hydroxide to be neutralised
Which of the following pairs of reactants would result in a reaction?
B
0.1
Asid etanoik
Natrium karbonat
2
0.1
Asid hidroklorik
Litium oksida
D
Kepekatan / mol dm–3
Hydrochloric acid
Karbon dioksida
C
Concentration / mol dm–3
Asid
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MODULE • Chemistry Form 4
9
Which of the following sodium hydroxide solutions have concentration of 1.0 mol dm–3? [Relative atomic mass: H=1, O=16, Na =23] Antara larutan natrium hidroksida berikut, yang manakah mempunyai kepekatan 1.0 mol dm–3? [JAR: H = 1, O = 16, Na = 23]
I
10 The diagram below shows 25.0 cm3 of 1.0 mol dm–3 of sulphuric acid and 50.0 cm3 of 1.0 mol dm–3 of sodium are added hydroxide solution to form solution A. Rajah di bawah menunjukkan 25.0 cm3 asid sulfurik 1.0 mol dm–3 dan 50.0 cm3 larutan natrium hidroksida 1.0 mol dm–3 ditambah bersama untuk menghasilkan larutan A.
5 g of sodium hydroxide dissolved in distilled water to make 250 cm3 of solution.
50 cm3 of 1 mol dm–3 of hydroxide solution 50 cm3 larutan natrium hidroksida 1 mol dm–3
5 g natrium hidroksida dilarutkan dalam air suling menjadikan 250 cm3 larutan.
II 20 g of sodium hydroxide dissolved in distilled water to make 500 cm3 of solution. 20 g natrium hidroksida dilarutkan dalam air suling menjadikan 500 cm3 larutan.
III 250 cm of 2 mol dm sodium hydroxide solution is added to distilled water to make 1 dm3 of solution. 3
–3
250 cm3 larutan natrium hidroksida 2 mol dm ditambah air suling menjadikan 1 dm3 larutan.
25 cm3 of 2.0 mol dm–3 sulphuric acid 25 cm3 asid sulfrik 2.0 mol dm–3
Solution A / Larutan A
–3
IV 500 cm3 of 2 mol dm–3 sodium hydroxide solution is added to distilled water to make 1 dm3 of solution. 500 cm3 larutan natrium hidroksida 2 mol dm–3 ditambah air suling menjadikan 1 dm3 larutan.
A I and III only I dan III sahaja
B
II and III only
C
II and IV only
II dan III sahaja II dan IV sahaja
Which of the following is true about the solution A? Antara berikut, yang manakah adalah benar tentang larutan A?
A The solution has a pH value of 7 Larutan itu menpunyai nilai pH 7
B
The solution will react with any acid
C
The solution turns a red litmus paper blue
Larutan itu boleh bertindak balas dengan sebarang asid Larutan itu menukarkan warna kertas litmus merah kepada biru
D The solution will react with zinc to produce hydrogen gas Larutan itu bertindak balas dengan zink untuk menghasilkan gas hidrogen
D I, II, III and IV
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Chemistry Form 4 • MODULE
SALT
7
GARAM PREPARATION OF SALTS / PENYEDIAAN GARAM
• THE MEANING OF SALTS / MAKSUD GARAM – To write the meaning of salts and the formulae for all types of salt that are commonly found in this topic. Menyatakan maksud garam dan menulis formula semua jenis garam yang biasa ditemui dalam tajuk ini.
• THE SOLUBILITY OF SALTS / KETERLARUTAN GARAM – To determine the solubility of nitrate, sulphate, carbonate and chloride salts. Menentukan keterlarutan semua garam nitrat, sulfat, karbonat dan klorida.
• EXPERIMENTS FOR THE PREPARATION OF SALTS BASED ON SOLUBILITY EKSPERIMEN PENYEDIAAN GARAM BERDASARKAN KETERLARUTAN
– To determine the suitable methods for the preparation of salts based on solubility: Menentukan kaedah yang sesuai bagi penyediaan garam berdasarkan keterlarutan:
–
i. Acid + metal / Asid + logam ii. Acid + metal oxides / Asid + oksida logam iii. Acid + alkali / Asid + alkali iv. Acid + metal carbonate / Asid + karbonat logam v. Double decomposition reaction / Tindak balas penguraian ganda dua To describe the experiments for each method of preparation and explain the rationale for each step. Menghuraikan eksperimen bagi setiap jenis kaedah penyediaan serta menerangkan rasional setiap langkah.
CALCULATION ON QUANTITY OF REACTANTS/PRODUCTS [ QUANTITATIVE ANALYSIS ] PENGHITUNGAN KUANTITI BAHAN/HASIL [ ANALISIS KUANTITATIF]
• CONTINUOUS VARIATIONS METHODS / KAEDAH PERUBAHAN BERTERUSAN – To describe the methods of experiment to determine the formulae of insoluble salts. Menghuraikan eksperimen bagi kaedah penentuan formula garam tak larut.
• SOLVING VARIOUS PROBLEMS RELATING TO QUANTITY OF REACTANTS/PRODUCTS IN SOLID, LIQUID AND GAS FORMS MENYELESAIKAN PELBAGAI MASALAH BERKAITAN KUANTITI BAHAN DALAM BENTUK PEPEJAL, LARUTAN DAN GAS – Using the formula / Menggunakan formula:
i. n =
MV 1 000
ii. Mole / Mol =
Mass / Jisim RAM/RMM/RFM / JAR/JMR/JFR
iii. The molar volume of gas at room temperature and s.t.p / Isi padu molar gas pada suhu bilik dan s.t.p
IDENTIFICATION OF IONS [ QUALITATIVE ANALYSIS ] / MENGENAL ION [ ANALISIS KUALITATIF ] • ACTION OF HEAT ON SALTS / KESAN HABA KE ATAS GARAM – To state the colour of the residue of lead(II) oxide, zinc oxide and copper(II) oxide. Menyatakan warna baki bagi plumbum(II) oksida, zink oksida dan kuprum(II) oksida.
– To state the confirmatory tests for carbon dioxide and nitrogen dioxide. Menyatakan ujian pengesahan bagi gas karbon dioksida dan nitrogen dioksida.
– To write the equations of the decomposition of carbonate and nitrate salts. Menulis persamaan penguraian semua garam karbonat dan nitrat.
• CONFIRMATORY TEST CATIONS AND ANIONS / UJIAN PENGESAHAN KATION DAN ANION – To state the confirmatory tests for all cations using sodium hydroxide and ammonia solution. Menghuraikan ujian pengesahan semua kation menggunakan natrium hidroksida dan larutan ammonia.
– To state the confirmatory tests to differentiate Al3+ and Pb2+. Menghuraikan ujian untuk membezakan Al3+ dan Pb2+.
– To state the confirmatory tests for anions of sulphate, nitrate, carbonate and chloride.
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Menghuraikan ujian pengesahan anion sulfat, nitrat, karbonat dan klorida.
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MODULE • Chemistry Form 4
PREPARATION OF SALT / PENYEDIAAN GARAM A salt is a compound formed when the hydrogen ion in an acid is replaced with metal ion or ammonium ion. Example: Sodium chloride, copper(II) sulphate, potassium nitrate and ammonium sulphate.
1
Garam ialah sebatian ion yang terhasil apabila ion hidrogen daripada asid diganti oleh ion logam termasuk ion ammonium. Contoh: natrium klorida, kuprum(II) sulfat, kalium nitrat dan ammonium sulfat.
Write the formulae of the salts in the table below by replacing hydrogen ion in sulphuric acid, hydrochloric acid, nitric acid and carbonic acid with metal ions or ammonium ion.
2
Tuliskan formula kimia garam berikut dengan menggantikan ion hidrogen dalam asid sulfurik, asid hidroklorik, asid nitrik dan asid karbonik dengan ion logam atau ion ammonium: Metal ion Ion logam
Sulphate salt (from H2SO4) Garam sulfat (dari H2SO4 )
Chloride salt (from HCl) Garam klorida (dari HCl)
Nitrate salt (from HNO3) Garam nitrat (dari HNO3 )
Carbonate salt (from H2CO3) Garam karbonat (dari H2CO3 )
Na+
Na2SO4
NaCl
NaNO3
Na2CO3
K+
K2SO4
KCl
KNO3
K2CO3
Mg2+
MgSO4
MgCl2
Mg(NO3 )2
MgCO3
Ca2+
CaSO4
CaCl2
Ca(NO3 )2
CaCO3
Al3+
Al2(SO4 )3
AlCl3
Al(NO3 )3
Al2(CO3 )3
Zn2+
ZnSO4
ZnCl2
Zn(NO3 )2
ZnCO3
Fe2+
FeSO4
FeCl2
Fe(NO3 )2
FeCO3
Pb2+
PbSO4
PbCl2
Pb(NO3 )2
PbCO3
Cu2+
CuSO4
CuCl2
Cu(NO3 )2
CuCO3
Ag+
Ag2SO4
AgCl
AgNO3
Ag2CO3
NH4+
(NH4 )2SO4
NH4Cl
NH4NO3
(NH4 )2CO3
Ba2+
BaSO4
BaCl2
Ba(NO3 )2
BaCO3
Solubility of salts in water: / Keterlarutan garam dalam air: (a) All K+, Na+ and NH4+ salts are soluble. / Semua garam K+, Na+ dan NH4+ larut. (b) All nitrate salts are soluble. / Semua garam nitrat larut. (c) All carbonate salts are insoluble except K2CO3, Na2CO3 and (NH4)2CO3. Semua garam karbonat tak larut kecuali K2CO3, Na2CO3 dan (NH4 )2CO3. (d) All sulphate salts are soluble except CaSO4, PbSO4 and BaSO4.
3
Semua garam sulfat larut kecuali CaSO4, PbSO4 dan BaSO4.
(e) All chloride salts are soluble except PbCl2 and AgCl. / Semua garam klorida larut kecuali PbCl2 dan AgCl. * Based on the solubility of the salts in water, shade the insoluble salts in the above table. * Berdasarkan keterlarutan garam dalam air, lorekkan garam yang tak larut dalam jadual di atas.
Method used to prepare salt depends on the solubility of the salt.
4
Kaedah penyediaan garam bergantung pada keterlarutan garam tersebut. Soluble salts are prepared from the reactions between an acid with a metal/ base/ metal carbonate: Garam terlarut disediakan melalui tindak balas antara asid dengan logam/bes/karbonat logam: i. Acid + metal / Asid + logam salt + hydrogen / garam + hidrogen Acid + *base salt + water ii. Acid + metal oxide / Asid + oksida logam salt + water / garam + air Asid + *bes garam + air iii. Acid + alkali / Asid + alkali salt + water / garam + air iv. Acid + metal carbonate / Asid + karbonat logam salt + water + carbon dioxide / garam + air + karbon dioksida
* Most bases are metal oxide or metal hydroxide. / Kebanyakan bes adalah oksida logam atau hidroksida logam. * All metal oxides and hydroxides are insoluble in water except Na2O, K2O, NaOH and KOH. Semua oksida logam dan hidroksida logam tidak larut dalam air kecuali Na2O, K2O, NaOH dan KOH.
* Alkali is a base that soluble in water and ionises to hydroxide ion.
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Alkali ialah bes yang larut dalam air dan mengion menjadi ion hidroksida.
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Salts are prepared based on their solubility as shown in the flow chart below:
Asid + Alkali Garam + Air (Tindak balas Peneutralan)
– Acid + Alkali Salt + Water (Neutralisation Reaction)
Garam ini disediakan melalui kaedah pentitratan di antara asid dan alkali dengan menggunakan penunjuk.
The salt is prepared by titration method of acid and alkali using an indicator.
Method I / Kaedah I
Salts / Garam K+, Na+, NH4+
Soluble salt Garam larut
Isi padu asid yang sama juga ditambah kepada isi padu alkali yang sama tanpa penunjuk untuk mendapatkan garam yang tulen dan neutral.
– The same volume of acid is then added to the same volume of alkali without any indicator to obtain pure and neutral salt solution.
Pentitratan dijalankan dengan menentukan isi padu asid yang diperlukan untuk meneutralkan alkali yang isi padunya sudah ditetapkan dengan menggunakan penunjuk.
Salt + Hydrogen (Displacement reaction)
Garam + Air + Karbon dioksida
Keringkan baki dengan menekankan antara kertas turas.
– Dry the residue by pressing it between filter papers.
Bilas baki dengan air suling.
– Rinse the residue with distilled water.
Turas dengan corong turas.
– Filter using filter funnel.
Kacau dengan rod kaca.
– Stir with glass rod.
Campur dua larutan yang mengandungi kation dan anion garam tak larut.
– Mix two solutions containing cations and anions of insoluble salts.
Garam ini disediakan melalui kaedah pemendakan. (Tindak balas penguraian ganda dua).
The salt is prepared by precipitation method. (Double decomposition reaction)
Method III / Kaedah III
Insoluble salt Garam tak larut
Turas dan keringkan hablur garam dengan menekan antara kertas turas.
– Cooled at room temperature / Biarkan sejuk pada suhu bilik. – Filter and dry the salt crystals by pressing them between filter papers.
Celupkan dengan rod kaca, jika hablur terbentuk dengan serta merta, larutan adalah tepu.
– Evaporate the filtrate until it becomes a saturated solution/ Sejatkan hasil turasan hingga larutan tepu. – Dip in a glass rod, if crystals are formed, the solution is saturated.
Turas campuran tersebut untuk mengeluarkan pepejal logam/oksida logam/karbonat logam yang berlebihan.
– Filter the mixture to remove excess metal/metal oxide/metal carbonate
Tambah serbuk logam/oksida logam/karbonat logam ke dalam isi padu tetap asid yang dihangatkan sehingga berlebihan.
volume of the heated acid
– Add metal/metal oxide/metal carbonate powder until excess into a fixed
Asid + Karbonat logam
Salt + Water + Carbon Dioxide
Garam + Air (Tindak balas Peneutralan)
– Acid + Metal carbonate
Asid + Oksida bes
Salt + Water (Neutralisation Reaction)
Garam + Hidrogen (Tindak balas penyesaran)
– Acid + Metal oxide
Asid + Logam
– Acid + Metal
Garam ini disediakan melalui tindak balas antara asid dengan logam/oksida logam/ karbonat logam yang tak larut:
The salt is prepared by reacting acid with insoluble metal/metal oxide/ metal carbonate:
Method II / Kaedah II
Other than / Garam selain K+, Na+, NH4+
Preparation of salt / Penyediaan garam
Garam disediakan berdasarkan keterlarutannya sebagaimana yang ditunjukkan pada carta aliran di bawah:
– A titration is conducted to determine the volume of acid needed to neutralise a fixed volume of an alkali with the aid of an indicator.
1
PREPARATION OF SOLUBLE AND INSOLUBLE SALT / PENYEDIAAN GARAM LARUT DAN GARAM TAK LARUT
Chemistry Form 4 • MODULE
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50 – 100
yang berlebihan.
3
0.5 – 2
–3
Hasil turasan ialah larutan garam
The filtrate is salt solution
logam/ Baki adalah logam oksida/ logam karbonat
Heat
Panaskan
Acid Asid
Salt crystals
hablur garam dengan Keringkan menekan antara kertas turas.
salt crystals by • Dry the pressing them between filter papers.
serbuk logam/ oksida logam/ karbonat logam pada isi padu asid yang Tambahkan tetap sambil dihangatkan perlahan-lahan .
.
.
Panaskan
Heat
Sejatkan larutan sehingga terbentuk.
Hablur
are terbentuk.
Baki adalah hablur garam
Residue is salt crystals
Turaskan campuran tersebut untuk mengasingkan hablur garam .
garam
Salt crystals
hablur garam
• Filter the mixture to separate the salt crystals .
Sejukkan pada suhu bilik sehingga
crystals salts
tepu
Larutan garam
salt solutions
Saturated
larutan tepu
Larutan garam dituangkan dalam mangkuk penyejat .
salt solution is poured into evaporating dish .
• Evaporate the salt solution until saturated solution is formed.
• The
• Cool it at room temperature until formed.
.
The residue is metal /metal oxide /metal carbonate .
Turas campuran tersebut untuk mengasingkan bahan berlebihan iaitu logam/oksida logam/karbonat logam larutan garam dengan .
• Filter the mixture to separate metal /metal oxide excess /metal carbonate with the salt solution .
cm of mol dm of any acid • Measure and pour and pour into a beaker. 50 – 100 Sukat dan tuangkan cm3 sebarang asid berkepekatan –3 0.5 – 2 mol dm dan tuangkan ke dalam bikar. • Add metal/metal oxide/ metal carbonate powder into the acid and heat gently .
Panaskan
Heat
Logam/oksida logam/ karbonat logam
Excess of metal/ metal oxide/ metal carbonate
Tambah serbuk logam / oksida logam / karbonat logam kepada asid sehingga berlebihan .
• Add metal/metal oxide / metal powder carbonate to the acid excess until .
campuran dengan Kacau rod kaca menggunakan .
• Stir the mixture with a glass rod .
Method II:/Kaedah II: Soluble salt except K+, Na+ and NH4+ / Garam larut selain K+, Na+ dan NH4+
2 Steps to Prepare Soluble Salt/Langkah Penyediaan Garam Larut Method I:/Kaedah I:
1 mol dm–3 sebarang asid dititratkan kepada alkali sehingga neutral menggunakan penunjuk. Isi padu asid yang digunakan dicatat.
1 mol dm–3 of any acid is titrated to the alkali until neutral by using an indicator. The volume of acid used is recorded.
Alkali Alkali
Acid Asid
Ulang titratan tanpa penunjuk untuk mendapatkan larutan garam yang tulen dan neutral .
• Repeat the titration without the indicator to get pure and neutral salt solution.
•
Sukat dan tuangkan 50 cm3 sebarang alkali berkepekatan 1 mol dm–3 ke dalam kelalang. Tambah beberapa titis fenolftalein.
• Measure and pour 50 cm3 of 1 mol dm–3 any alkali into a conical flask. Add a few drops of phenolphthalein.
Garam larut K+, Na+ dan NH4+
Soluble salt of K+, Na+ and NH4+
MODULE • Chemistry Form 4
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Chemistry Form 4 • MODULE
3
Steps to Prepare Insoluble Salt / Penyediaan Garam Tak Larut Insoluble salts are prepared by the precipitation method through double decomposition reactions. Garam tak larut disediakan dengan cara pemendakan melalui tindak balas penguraian ganda dua. (i) In this reaction, the precipitate of insoluble salt is formed when two different solutions that contain the cation and anion of the insoluble salt are mixed. Dalam tindak balas ini, mendakan garam tak larut terbentuk apabila dua larutan berbeza yang mengandungi kation dan anion garam tak terlarut dicampurkan.
(ii) The insoluble salt is obtained as a residue of a filtration. Garam tak terlarut tersebut diperoleh daripada baki penurasan. Method III: Preparation of Insoluble XnYm Salt by Double Decomposition Reaction Kaedah III: Penyediaan Garam Tak Larut XnYm Melalui Tindak balas Penguraian Ganda Dua 1) Measure and pour 50 – 100 cm3 0.5 – 2 of mol dm–3 of aqueous solution contains X m+ cation.
2) Measure and pour 50 – 100 cm3 0.5 – 2 mol dm–3 of of aqueous solution contains Yn– anion into another beaker.
Sukat dan tuangkan 50 – 100 cm3 0.5 – 2 mol dm–3 larutan berkepekatan mengandungi kation Xm+ ke dalam bikar.
Precipitate of salt is formed.
XnYm
Sukat dan tuangkan 50 – 100 cm3 0.5 – 2 larutan berkepekatan mol dm–3 mengandungi anion Yn– ke dalam bikar yang lain.
3) Mix both solutions and stir the glass rod .
Campur dan kacaukan rod kaca .
XnYm
Mendakan garam terbentuk.
The residue is salt.
XnYm
Mendakan adalah garam XnYm .
mixture
campuran
with
menggunakan
4)
Filter the with salt.
mixture
distilled water
and
rinse
the precipitate
. The residue is
XnYm
Turas campuran dan bilas mendakan itu menggunakan air suling. Baki ialah garam XnYm.
Salt
XnYm
5)
Press the precipitate
between
filter papers to dry it.
Tekankan mendakan antara kertas turas untuk mengeringkannya.
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MODULE • Chemistry Form 4
Complete the following table: Lengkapkan jadual berikut: X m+
Yn–
XnYm
Pb2+ [Pb(NO3)2]
I– [KI]
PbI2
Ba2+[ BaCl2 ]
SO4 [ Na2SO4 ]
BaSO4
Ag+ [AgNO3]
Cl– [NaCl]
AgCl
Ag+ + Cl–
Ca2+ [Ca(NO3)2]
CO32– [Na2CO3]
CaCO3
Ca2+ + CO32–
2–
Ion equation/Persamaan ion
Pb2+ + I–
Ba2+ + SO42–
PbI2
BaSO4 AgCl CaCO3
Complete the following table by writing “S” for soluble salts and “IS” for insoluble salts. Write all the possible chemical equations to prepare soluble salts and two chemical equations for insoluble salts.
4
Lengkapkan jadual berikut dengan menulis “L” bagi garam larut dan “TL” bagi garam tak larut. Tuliskan semua persamaan kimia dalam penyediaan garam larut dan dua persamaan kimia bagi garam tak larut. Salt
Garam
Zinc chloride Zink klorida
“S” / “IS”
Chemical equations
“L” / “TL”
Persamaan kimia
ZnCl + H 2 2 ZnCl + CO + H O ZnCO3 + 2HCl 2 2 2 ZnCl + H O ZnO + 2HCl Zn + 2HCl
S
2
Sodium nitrate Natrium nitrat
Silver chloride Argentum klorida
Copper(II) sulphate Kuprum(II) sulfat
Lead(II) sulphate Plumbum(II) sulfat
Aluminium nitrate Aluminium nitrat
Lead(II) chloride Plumbum(II) klorida
Magnesium nitrate Magnesium nitrat
Potassium chloride Kalium klorida
Lead(II) nitrate Plumbum(II) nitrat
Barium sulphate
m
IS
S
IS
NaNO + H O 3 2
NaOH + HNO3
AgCl + HNO
AgNO3 + HCl
3
AgCl + NaNO 3
AgNO3 + NaCl
CuSO + H O 4 2 CuSO + CO + H O CuCO3 + H2SO4 4 2 2
CuO + H2SO4
Pb(NO3)2 + H2SO4 Pb(NO3)2 + Na2SO4
PbSO + 2HNO 4 3 PbSO + 2NaNO 4
3
2Al(NO ) + 3H 3 3 2 2Al(NO ) + 3H O Al2O3 + 6HNO3 3 3 2 2Al(NO ) + 3CO + 3H O Al2(CO3)3 + 6HNO3 3 3 2 2 2Al + 6HNO3
S
IS
Pb(NO3)2 + 2HCl Pb(NO3)2 + 2NaCl
PbCl + 2HNO 2 3 PbCl + 2NaNO 2
3
Mg(NO ) + H 3 2 2 Mg(NO ) + H O MgO + 2HNO3 3 2 2 Mg + 2HNO3
S
MgCO3 + 2HNO3
Mg(NO3)2 + CO2 + H2O
KCl + H O 2
S
KOH + HCl
S
Pb(NO ) + H O 3 2 2 Pb(NO ) + CO + H O PbCO3 + 2HNO3 3 2 2 2
IS
PbO + 2HNO3
BaCl2 + H2SO4 BaCl2 + Na2SO4
BaSO + 2HCl 4 BaSO + 2NaCl 4
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S
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Chemistry Form 4 • MODULE
EXERCISE / LATIHAN 1
The diagram below shows the set-up of apparatus to prepare soluble salt Y. Rajah di bawah menunjukkan susunan radas bagi menyediakan garam larut Y.
Nitric acid Asid nitrik
25 cm3 of 1 mol dm–3 potassium hydroxide solution + phenolphthalein 25 cm3 larutan kalium hidroksida 1 mol dm-3 + fenolftalein
Phenolphthalein is used as an indicator in a titration between nitric acid and sodium hydroxide solution. 25 cm3 of nitric acid completely neutralises 25 cm3 of 1 mol dm–3 potassium hydroxide solution. The experiment is repeated by reacting 25 cm3 of 1 mol dm–3 potassium hydroxide solution with 25 cm3 nitric acid without phenolphthalein. Salt Y is formed from the reaction. Fenolftalein digunakan sebagai penunjuk dalam pentitratan antara asid nitrik dengan larutan kalium hidroksida. 25 cm3 asid nitrik meneutralkan 25 cm3 larutan kalium hidroksida 1 mol dm–3. Eksperimen ini diulang dengan menindakbalaskan 25 cm3 larutan kalium hidroksida 1 mol dm–3 dengan 25 cm3 asid nitrik tanpa fenolftalein. Garam Y terbentuk daripada tindak balas ini.
(a) Name salt Y. Nyatakan nama garam Y.
Potassium nitrate (b) Write a balanced equation for the reaction that occurs. Tuliskan persamaan seimbang bagi tindak balas yang berlaku.
HNO3 + KOH
KNO3 + H2O
(c) Calculate the concentration of nitric acid. Hitungkan kepekatan asid nitrik tersebut.
1 = 0.025 mol 1 000 From the equation, 1 mol of KOH : 1 mol of HNO3 0.025 mol of KOH : 0.025 mol of HNO3 Concentration of HNO3, M 25 0.025 = M × 1 000 M = 1 mol dm–3 Mol of NaOH = 1 ×
(d) Why is the experiment is repeated without phenolphthalein? Mengapakah eksperimen ini diulang tanpa menggunakan fenolftalein?
To get pure and neutral salt solution Y. (e) Describe briefly how a crystal of salt Y is obtained from the salt solution. Huraikan secara ringkas bagaimana hablur garam Y diperoleh daripada larutan garamnya.
– The salt solution is poured into an evaporating dish. – The solution is heated to evaporate the solution until one third its original volume// a saturated solution formed. – The saturated solution is allowed to cool until salt crystals Y are formed. – The crystals are filtered and dried by pressing them between filter papers. (f) Name two other salts that can be prepared with the same method. Namakan dua garam lain yang boleh disediakan dengan kaedah yang sama.
Potassium/sodium/ammonium salt. Example: potassium nitrate, sodium sulphate. (g) State the type of reaction in the preparation of the salts. Nyatakan jenis tindak balas dalam penyediaan garam ini. n io
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Neutralisation
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MODULE • Chemistry Form 4
The following is the steps in the preparation of dry copper(II) sulphate crystals.
2
Berikut adalah langkah-langkah dalam penyediaan hablur garam kuprum(II) sulfat kering.
Step I:
Copper(II) oxide powder is added a little at a time with constant stirring to the heated 50 cm3 of 1 mol dm–3 sulphuric acid until some of it no longer dissolve.
Langkah I: Serbuk kuprum(II) oksida ditambahkan, sedikit demi sedikit sambil dikacau ke dalam 50 cm3 asid sulfurik 1 mol dm-3 yang dipanaskan sehingga serbuk itu tidak boleh larut lagi.
Step II:
The mixture is filtered.
Langkah II: Campuran dituras.
Step III:
The filtrate is poured into an evaporating dish and heated to evaporate the solution until one third of its original.
Langkah III: Hasil turasan dipanaskan di dalam mangkuk penyejat sehingga isi padunya menjadi satu pertiga daripada isi padu asal.
Step IV:
The salt solution is allowed to cool at room temperature for the crystallisation to take place.
Langkah IV: Hasil turasan itu dibiarkan sejuk ke suhu bilik sehingga penghabluran berlaku.
Step V:
The crystals formed are filtered and dried by pressing them between filter papers.
Langkah V: Hablur yang terbentuk dituraskan dan dikeringkan dengan menekan antara kertas turas.
(a) (i)
State two observations during Step I. Nyatakan dua pemerhatian pada Langkah I.
– Black solid dissolve – Colourless solution turns black
(ii) Write a balance chemical equation for the reaction that occur in Step I. Tuliskan persamaan kimia seimbang bagi tindak balas yang berlaku dalam Langkah I.
CuO + H2SO4
CuSO4 +H2O (iii) State the type of reaction in the preparation of the salts. Nyatakan jenis tindak balas yang berlaku dalam penyediaan garam.
Neutralisation (b) Why is copper(II) oxide powder added until some of it no longer dissolve in Step I? Mengapakah serbuk kuprum(II) oksida ditambah pada larutan tersebut sehingga ia tidak boleh melarut lagi dalam Langkah I?
To make sure that all sulphuric acid has reacted. (c) What is the purpose of heating in Step III? Apakah tujuan pemanasan dalam Langkah III?
To evaporate the water and copper(II) sulphate solution becomes saturated (d) What is the colour of copper(II) sulphate? Apakah warna kuprum(II) sulfat?
Blue (e) What is the purpose of filtration in
Apakah tujuan penurasan dalam (i) Step II? / Langkah II?
– To remove the excess copper(II) oxide. – To obtain copper(II) sulphate solution as a filtrate
(ii) Step V? / Langkah V?
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Chemistry Form 4 • MODULE
(f) Draw the a labelled diagram to show the set-up of apparatus used Step II and Step III. Lukiskan gambar rajah berlabel untuk menunjukkan susunan alat radas yang digunakan dalam Langkah II dan Langkah III. Filter paper
Excess of copper(II) oxide
Copper(II) sulphate solution
Heat Copper(II) sulphate solution (g) Can copper powder replace copper(II) oxide in the experiment? Explain your answer. Bolehkah serbuk kuprum digunakan untuk menggantikan kuprum(II) oksida dalam eksperimen ini? Terangkan jawapan anda. Cannot. Copper is less electropositive than hydrogen in the electrochemical series, copper cannot displace hydrogen from the acid. (h) Name other substance that can replace copper(II) oxide to prepare the same salt. Write a balance chemical equation for the reaction that occur. Namakan sebatian lain yang dapat menggantikan kuprum(II) oksida dalam penyediaan garam yang sama. Tuliskan persamaan kimia yang seimbang bagi tindak balas yang berlaku.
3
Copper(II) carbonate
Substance / Garam larut :
Balance equation / Persamaan seimbang :
CuCO3 + H2SO4
CuSO4 + H2O + CO2
The diagram below shows the flow chart for the preparation of lead(II) nitrate and lead(II) sulphate through reaction I and II. Rajah di bawah menunjukkan carta aliran bagi penyediaan plumbum(II) nitrat dan plumbum(II) sulfat melalui tindak balas I dan II. Reaction I Tindak balas I
Lead(II) carbonate
Lead(II) nitrate
Plumbum(II) karbonat
(a) (i)
Reaction II Tindak balas II
Plumbum(II) nitrat
Lead(II) sulphate Plumbum(II) sulfat
What is meant by salt? Apakah maksud garam?
Salts are ionic compounds produced when hydrogen ion from acid is replaced with metal ion including ammonium ion.
(ii) Based on the flow chart above, classify the above salt to soluble salt and insoluble salt. Berdasarkan carta aliran di atas, kelaskan garam-garam tersebut kepada garam larut dan garam tak larut.
Soluble salt / Garam larut : Lead(II) nitrate
Insoluble salt / Garam tak larut : Lead(II) carbonate, Lead(II) sulphate
(b) (i)
Describe how lead(II) nitrate solution is obtained in reaction I. Terangkan bagaimana larutan plumbum(II) nitrat diperoleh daripada tindak balas I.
–
Measure Sukat
and pour sebanyak
– Lead(II) carbonate Serbuk
– Stir the
cm3 of 1 mol dm–3 cm asid 3
nitrik
nitric
acid in a beaker.
1 mol dm dan tuangkan ke dalam bikar. -3
is added to the acid in the beaker until
plumbum(II) karbonat ditambahkan kepada asid di dalam bikar sehingga
mixture
Campuran
– The
powder
50 50
mixture
Campuran
.
berlebihan
.
with a glass rod.
tersebut dikacau dengan rod kaca.
in the beaker is filtered. dituraskan.
– The filtrate is lead(II) nitrate larutan
solution
.
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Hasil turasan ialah
excess
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MODULE • Chemistry Form 4
(ii) Write a balanced chemical equation for the reaction that occur. Tuliskan persamaan kimia yang seimbang bagi tindak balas yang berlaku.
(c) (i)
PbCO3 + HNO3
Pb(NO3)2 + H2O + CO2
Describe how to prepare pure and dry lead(II) sulphate in reaction II. Huraikan bagaimana cara menyediakan plumbum(II) sulfat yang tulen dan kering dalam tindak balas II.
–
50 cm3
1 mol dm–3 lead(II) nitrate solution is added to of sodium sulphate solution in a beaker. 50 cm3 larutan plumbum(II) nitrat 1 mol dm–3 ke dalam bikar.
– The
mixture
– The
mixture
Campuran
mol dm–3 ditambahkan kepada
of
50 cm3
1
mol dm–3
larutan natrium sulfat
is stirred with glass rod. tersebut dikacau dengan rod kaca.
Campuran
is filtered. The white precipitate of lead(II) sulphate is collected as the residue. dituraskan. Mendakan putih plumbum(II) sulfat dikumpulkan sebagai baki.
– The precipitate is rinsed with Mendakan tersebut dibilas dengan
– The precipitate is Mendakan tersebut
1
50 cm3
distilled water air suling
. .
pressed
between sheets of
ditekan
antara
kertas turas
filter papers to dry it. .
(ii) Write an ionic equation the reaction that occur. Tuliskan persamaan ion bagi tindak balas yang berlaku.
2+ 2– Pb + SO4
PbSO4
(iii) Name the type of reaction that occur in reaction II. Namakan jenis tindak balas yang berlaku dalam tindak balas II.
Double decomposition reaction
(iv) What is the step taken to make sure that pure lead(II) sulphate in reaction II is pure? Apakah langkah yang diambil untuk memastikan plumbum(II) sulfat dalam tindak balas II tulen?
(d) (i)
The precipitate is rinsed with distilled water. Can lead(II) sulphate be prepared by adding excess of lead(II) nitrate to calcium(II) sulphate followed by filtration. Explain your answer. Bolehkah plumbum(II) sulfat disediakan dengan menambahkan plumbum(II) nitrat berlebihan kepada kalsium(II) sulfat dan diikuti dengan penurasan? Terangkan jawapan anda.
– Cannot. – Calcium sulphate is insoluble salt, it cannot form a solution and there are no free moving ions. – Double decomposition reaction cannot occur.
(ii) Can lead(II) sulphate be prepared by adding excess of lead(II) oxide to sulphuric acid. Explain your answer. Bolehkah plumbum(II) sulfat disediakan dengan menambahkan plumbum(II) oksida berlebihan kepada asid sulfurik? Terangkan jawapan anda.
– Cannot. – Lead(II) sulphate and lead(II) oxide are insoluble, both cannot be separated by filtration.
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– The insoluble lead(II) sulphate will prevent lead(II) oxide to undergo further reaction with sulphuric acid.
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Chemistry Form 4 • MODULE
4
The diagram below shows the flow chart for the preparation of zinc carbonate and zinc sulphate through reactions I and II. Rajah di bawah menunjukkan carta aliran bagi penyediaan garam zink karbonat dan zink sulfat melalui tindak balas I dan tindak balas II.
Zinc nitrate
Reaction I Tindak balas I
Zinc carbonate
Zink nitrat
Reaction II Tindak balas II
Zinc sulphate
Zink karbonat
Zink sulfat
(a) Based on the flow chart above, classify the above salt to soluble salt and insoluble salt. Berdasarkan carta aliran di atas, kelaskan garam di atas kepada garam larut dan garam tak larut.
Soluble salt / Garam larut : Zinc nitrate, zinc sulphate
Insoluble salt / Garam tak larut : Zinc carbonate
(b) (i)
State the reactant for the preparation of zinc carbonate from zinc nitrate in reaction I. Nyatakan bahan tindak balas untuk penyediaan zink karbonat dalam tindak balas I.
Sodium carbonate solution / potassium carbonate solution / ammonium carbonate solution
(ii) State the type of reaction the occurs in reaction I. Nyatakan jenis tindak balas yang berlaku dalam tindak balas I.
Double decomposition (iii) Describe the preparation zinc carbonate from zinc nitrate in the laboratory through reaction I. Huraikan penyediaan zink karbonat dari zink nitrat melalui tindak balas I.
– 50 cm3 of 1 mol dm–3 zinc nitrate solution is added to 50 cm3 of 1 mol dm–3 sodium carbonate solution in a beaker. – The mixture is stirred with a glass rod and a white solid, ZnCO3 is formed. – The mixture is filtered and the residue is rinsed with distilled water. – The white precipitate is dried by pressing it between filter papers. (iv) Write the chemical equation for the reaction in (b)(iii). Tuliskan persamaan kimia untuk tindak balas yang berlaku dalam (b)(iii).
Zn(NO3)2 + Na2CO3 (c) (i)
ZnCO3 + 2NaNO3
State the reactant for the preparation of zinc sulphate from zinc carbonate in reaction II. Nyatakan bahan tindak balas bagi penyediaan zink sulfat dari zink karbonat dalam tindak balas II.
Sulphuric acid (ii) Describe laboratory experiment to prepare zinc sulphate from zinc carbonate through reaction II. Huraikan eksperimen dalam makmal untuk menyediakan zink sulfat dari zink karbonat melalui tindak balas II. – 50 cm3 of 1 mol dm–3 of sulphuric is measured and poured into acid in a beaker. – The white precipitate from reaction I/ zinc carbonate powder is added to the acid until in excess. – The mixture is stirred with a glass rod. – The excess white precipitate is filter out.
– The filtrate is poured into an evaporating dish.
– The salt solution is gently heated until saturated.
– The hot saturated salt solution is allowed to cool for crystals to form.
– The crystals formed are filtered and dried by pressing it between sheets of filter papers. (iii) Write the chemical equation for the reaction in (c)(ii). Tuliskan persamaan kimia untuk tindak balas yang berlaku dalam (c)(ii).
ZnSO4 + H2O + CO2 n io
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ZnCO3 + H2SO4
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MODULE • Chemistry Form 4
Constructing Ionic Equation for the Formation of Insoluble Salt Membina Persamaan Ion bagi Pembentukan Garam Tak Larut
The ionic equation for the formation of insoluble salt can be constructed if the number of moles of anion and cation to form 1 mol of insoluble salt are known.
1
Persamaan kimia untuk pembentukan garam tak terlarut dapat ditulis jika bilangan mol anion dan kation untuk membentuk 1 mol garam tak larut diketahui.
The number mol of cation and anion which combined to form 1 mol of insoluble salt is determined experimentally by a continuous method:
2
Bilangan mol kation dan anion yang bergabung untuk membentuk 1 mol garam tak terlarut dapat ditentukan secara eksperimen menggunakan kaedah perubahan berterusan:
(a) A fixed volume of a solution A contains cations, Xm+ of the insoluble salt reacts with increasing volume of another solution B contains the anions, Yn– of the insoluble salt. Isi padu tetap larutan A mengandungi kation, X m+ daripada garam tak terlarut bertindak balas dengan isi padu yang meningkat larutan B yang mengandungi anion, Y n– daripada garam tak terlarut.
(b) The volume of solution B needed to completely react with fixed volume of solution A is determined. Isi padu larutan B yang diperlukan untuk bertindak balas dengan isi padu larutan A yang ditetapkan ditentukan.
(c) The number of mol of Xm+ react with Yn– is calculated based on the result of the experiment. Bilangan mol X m+ yang bertindak balas dengan Y n– dihitung berdasarkan keputusan eksperimen.
(d) The simplest ration of mol of Xm+: mol of Yn– is calculated. Nisbah di antara bilangan mol X m+: bilangan mol Y n– dihitung.
(e) Use the ratio to construct ionic equation. Gunakan nisbah tersebut untuk membina persamaan ion.
Example: / Contoh: 5.0 cm³ of 0.5 mol dm–3 copper(II) sulphate solution is poured to 8 test tubes with the same size. Different volume of 1.0 mol dm–3 potassium hydroxide solution are added to each test tube. The test tubes are stoppered and shaken well. The test tubes are left for 30 minutes. The height of precipitate formed in each test tube is measured. The graph below is obtained when the height of precipitate is plotted against the volume of potassium hydroxide solution.
3
5.0 cm³ larutan kuprum(II) sulfat 0.5 mol dm–3 dituang ke dalam setiap 8 tabung uji yang mempunyai saiz yang sama. Larutan kalium hidroksida 1.0 mol dm–3 yang berlainan isi padu ditambah kepada setiap tabung uji. Tabung uji tersebut digoncangkan dan dibiarkan selama 30 minit. Tinggi mendakan yang terbentuk dalam setiap tabung uji diukur. Graf di bawah diperoleh apabila ketinggian mendakan diplot melawan isi padu larutan kalium hidroksida. Height of precipitate (cm) / Tinggi mendakan (cm)
5
0 (a) (i)
Volume of potassium hydroxide /cm3 1
2
3
4
5
6
7
8
9
Isi padu kalium hidroksida /cm3
Name the precipitate formed. Nyatakan nama mendakan yang terbentuk.
Copper(II) hydroxide
(ii) What is the colour of the precipitate? Apakah warna mendakan?
Blue (b) Based on the above graph, what is the volume of potassium hydroxide solution needed to completely react with copper(II) sulphate solution? Berdasarkan graf di atas, apakah isi padu larutan kalium hidroksida yang diperlukan untuk bertindak balas dengan larutan kuprum(II) sulfat secara lengkap?
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Chemistry Form 4 • MODULE
(c) (i)
Calculate the number of moles of copper(II) ions in 5.0 cm³ of 0.5 mol dm–3 copper(II) sulphate solution. Hitung bilangan mol ion kuprum(II) dalam 5.0 cm³ larutan kuprum(II) sulfat 0.5 mol dm–3.
CuSO4
Cu2+ + SO42– 5 × 0.5 = 0.0025 mol Mol of CuSO4 = 1 000 From the equation, 1 mol CuSO4 : 1 mol Cu2+ 0.0025 mol CuSO4 : 0.0025 mol Cu2+
(ii) Calculate the number of mol of hydroxide ions needed to react with 5.0 cm³ of 0.5 mol dm–3 copper(II) sulphate solution. Hitung bilangan mol ion hidroksida yang diperlukan untuk bertindak balas dengan 5.0 cm³ larutan kuprum(II) sulfat 0.5 mol dm–3.
KOH
K+ + OH– Mol of KOH = 5 × 1.0 = 0.005 mol 1 000 From the equation, 1 mol KOH : 1 mol OH– 0.005 mol KOH : 0.005 mol OH– (iii) How many moles of hydroxide ions react with one mole of copper(II) ions to form a precipitate? Berapakah bilangan mol ion hidroksida yang bertindak balas dengan satu mol ion kuprum(II) untuk membentuk mendakan?
0.0025 mol Cu2+ : 0.005 mol OH– 1 mol Cu2+ : 2 mol of OH– (d) Calculate the number of mol of hydroxide ions needed to react with 5.0 cm³ of 0.5 mol dm–3 copper (II) sulphate solution. Tuliskan persamaan ion bagi pembentukan mendakan.
Cu2+ + 2OH–
Cu(OH)2
Solving Numerical Problems Involving the Salt Preparation Penghitungan Pelbagai Masalah Melibatkan Penyediaan Garam Mass in gram Jisim dalam gram
÷ (RAM/RMM/RFM) g mol–1 ÷ (JAR/JMR/JFR) g mol–1
Solution concentration in mol dm–3 (M) and volume in cm3 (V) Kepekatan larutan dalam mol dm–3 (M) dan isi padu dalam cm3 (V)
MV n = 1000
× (RAM/RMM/RFM) g mol–1 × (JAR/JMR/JFR) g mol–1 × 24 dm3 mol–1/22.4 dm3 mol–1
Number of mol (n)
Volume of gas in dm3
Bilangan mol (n)
Isi padu gas dalam dm3 ÷ 24 dm mol /22.4 dm mol 3
–1
3
–1
Gas occupies the volume of 24 dm3 at room temperature and 22.4 dm3 at s.t.p (standard temperature and pressure). 1 mol sebarang gas menempati isipadu 24 dm3 pada suhu bilik dan 22.4 dm3 pada s.t.p (suhu dan tekanan piawai). Calculation steps: / Langkah-langkah pengiraan:
S1 Write a balanced equation. L1
Tuliskan persamaan seimbang.
S2 Write the information from the question above the equation. L3
Tuliskan maklumat daripada soalan di atas persamaan tersebut.
S3 Write the information from the chemical equation below the equation (the number of moles of reactants/products). L3
Tuliskan maklumat daripada persamaan kimia di bawah persamaan tersebut (bilangan mol bagi bahan/hasil tindak balas).
S4 Change the information in S2 into moles by using the method shown in the chart below. L4
Tukar maklumat dalam L2 menjadi mol dengan menggunakan kaedah yang ditunjukkan dalam carta di atas.
S5 Use the relationship between number of moles of substance involved in S3 to find the answer. L5
Gunakan perhubungan bilangan mol bahan terlibat dalam L3 untuk mendapatkan jawapan.
S6 Change the information to the unit required using the chart below. Tukar maklumat tersebut kepada unit yang dikehendaki mengikut carta di atas. n io
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MODULE • Chemistry Form 4
EXERCISE / LATIHAN
50 cm3 of 2 mol dm–3 sulphuric acid is added to an excess of copper(II) oxide powder. Calculate the mass of copper(II) sulphate formed in the reaction. [Relative atomic mass: H = 1, O = 16, Cu = 64, S = 32]
1
50 cm3 asid sulfurik 2 mol dm–3 ditambah kepada serbuk kuprum(II) oksida berlebihan. Hitungkan jisim kuprum(II) sulfat yang terbentuk dalam tindak balas itu. [Jisim atom relatif: H = 1, O = 16, Cu = 64, S = 32]
M = 2 mol dm–3 V = 50 cm3 CuO(aq) + H2SO4(aq)
? g CuSO4(ak) + 2H2O(l) 2 × 50 Number of moles of sulpuric acid = = 0.1 mol 1 000 From the equation, 1 mol CuO : 1 mol CuSO4 0.1 mol CuO : 0.1 mol CuSO4 Mass of CuSO4 = 0.1 mol × [64 + 32 + (16 × 4)] g mol–1 = 16 g
27.66 g of lead(II) iodide is precipitated when 2.0 mol dm–3 of aqueous lead(II) nitrate solution is added to an excess of aqueous potassium iodide solution. Calculate the volume of aqueous lead(II) nitrate solution used. [Relative atomic mass: I = 127, Pb = 207]
2
27.66 g plumbum(II) iodida termendak apabila 2.0 mol dm–3 larutan plumbum(II) nitrat akueus ditambahkan kepada larutan kalium iodida akueus berlebihan. Hitungkan isi padu plumbum(II) nitrat yang digunakan. [Jisim atom relatif: I = 127, Pb = 207]
M = 2 mol dm–3 V = ? cm3 Pb(NO3)2(aq) + 2KI(aq)
Mol of PbI2 =
From the equation,
n mol 0.06 mol = = 0.03 dm3 = 30 cm3 Volume of Pb(NO3)2 = M mol dm–3 2 mol dm–3
3
Zinc oxide powder is added to 100 cm3 of 2 mol dm–3 nitric acid to form zinc nitrate. Calculate
25 g PbI2(s) + 2KNO3(aq)
27.66 = 0.06 mol (207 + 2 × 127) 1 mol PbI2 : 1 mol Pb(NO3)2 0.06 mol PbI2 : 0.06 mol Pb(NO3)2
Serbuk zink oksida ditambahkan kepada 100 cm3 asid nitrik 2 mol dm–3 untuk membentuk zink nitrat. Hitungkan
(i) the mass of zinc oxide that has reacted. jisim zink oksida yang bertindak balas.
(ii) the mass of zinc nitrate produced. [Relative atomic mass: H = 1, O = 16, Cl = 35.5, Zn = 65]
m
(i) 2HNO3(aq) + ZnO(s)
Zn(NO3)2(aq) + H2O(l)
(ii) From the equation, 2 mol of HNO3 : 1 mol of Zn(NO3)2 0.2 mol of HNO3 : 0.1 mol of Zn(NO3)2 Mass of Zn(NO3)2 = 0.1 mol × [65 +[14 + (16 × 3)] × 2] g mol–1 = 0.1 × 189 = 18.9 g
100 × 2 = 0.2 mol 1 000 From the equation, 2 mol of HNO3 : 1 mol of ZnO 0.2 mol of HNO3 : 0.1 mol of ZnO Mass of ZnO = 0.1 × [65 + 16] = 8.1 g Number of moles of HNO3 =
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Chemistry Form 4 • MODULE
4
200 cm3 of 1 mol dm–3 barium chloride solution reacts 100 cm3 of 1 mol dm–3 silver nitrate solution. Calculate the mass of precipitate produced. [Relative atomic mass Ag = 108, Cl = 35.5] 200 cm3 larutan barium klorida 1 mol dm–3 bertindak balas dengan 100 cm3 larutan argentum nitrat 1 mol dm–3. Hitungkan jisim mendakan yang terbentuk. [Jisim atom relatif: Ag = 108, Cl = 35.5]
M = 0.1 mol dm–3 V = 100 cm3
2AgNO3 2AgCl + Ba(NO3)2 1 × 200 Mol of barium chloride = = 0.2 mol (excess) 1 000 1 × 100 = 0.1 mol Mol of silver nitrate = 1 000 From the equation, 1 mol of BaCl2 : 2 mol of AgNO3 : 2 mol of AgCl 0.2 mol of BaCl2 (lebih) : 0.1 mol of AgNO3 : 0.1 mol of AgCl Mass of AgCl = 0.1 mol × [108 + 35.5] g mol–1 = 14.35 g
BaCl2
M = 0.2 mol dm–3 V = 100 cm3, ? g
+
Qualitative Analysis of Salts / Analisis Kualitatif Garam 1
Qualitative analysis of a salt is a chemical technique to identify the ions present in a salt. Analisis kualitatif garam ialah suatu teknik dalam kimia yang digunakan untu mengenal pasti ion-ion yang hadir dalam garam.
2
The qualitative analysis consists of the following steps: Analisis kualitatif terdiri daripada langkah-langkah berikut: (a) Observe the physical properties on salt. Perhatikan sifat-sifat fizik garam. (b) The action of heat on salts. Kesan haba ke atas garam. (c) Prepare aqueous solution of salts and conduct confirmatory test for cation and anion present. Sediakan larutan akueus garam dan menjalankan ujian pengesahan untuk kation dan anion yang hadir.
Physical Properties of Salt Sifat-Sifat Fizik Garam 1
Physical properties such as colour and solubility indicate the possibility of the presence of certain cations, anions or metal oxide. Sifat-sifat fizikal seperti warna dan keterlarutan menunjukkan kemungkinan kehadiran kation, anion atau oksida logam tertentu. Pepejal
Larutan akueus
Aqueous
Salts/ Cation/Metal oxide
White Putih
Colourless Tanpa warna
K+, Na+, Ca2+, Mg2+, Al3+, Zn2+, Pb2+, NH4+
Green Hijau
Insoluble Tak larut
CuCO3
Light green Hijau muda
Light Green Hijau muda
Fe2+, contoh: FeSO4, FeCl2, Fe(NO3)2
Blue Biru
Blue Biru
CuSO4, Cu(NO3 )2 dan CuCl2
Brown Perang
Brown Perang
Fe3+
Black Hitam
Insoluble Tak larut
CuO
Yellow when hot, white when cold Kuning apabila panas, putih apabila sejuk
Insoluble Tak larut
ZnO
Brown when hot, yellow when cold Perang apabila panas, kuning apabila sejuk
Insoluble Tak larut
PbO
Garam/Kation/Oksida logam
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MODULE • Chemistry Form 4
Action of Heat on Salt / Kesan Haba ke atas Garam
Some salts decompose when they are heated:
1
Beberapa jenis garam terurai apabila dipanaskan:
Salt
metal oxide
Garam
oksida logam
+
gas gas
Common Gas Identification: / Pengesahan Gas yang biasa:
2
Gas Gas
Observation/ Test Pemerhatian/Ujian
Nitrogen dioxide, NO2 Nitrogen dioksida, NO2
Oxygen,O2 Oksigen,O2
Carbon dioxide, CO2 Karbon dioksida, CO2
Inference Inferens
– Brown gas. Wasap perang. – Place a moist blue litmus paper at the mouth of the boiling tube, blue litmus paper turns red. Letakkan kertas litmus biru lembap pada mulut tabung didih, kertas litmus biru bertukar menjadi merah.
– Nitrogen dioxide gas is produced by heating nitrate salt. Nitrogen dioksida terhasil apabila garam nitrat dipanaskan. – Nitrate ion, NO3– present. Ion nitrat, NO3– hadir.
– Colourless gas. Gas tanpa warna. – Put a glowing wooden splinter near to the mouth of a boiling tube, the glowing wooden splinter is relighted. Dekatkan kayu uji berbara ke mulut tabung didih, kayu uji berbara menyala.
– Oxygen gas is produced by heating nitrate or chlorate(V) salt. Gas oksigen terhasil apabila garam nitrat atau klorat(V) dipanaskan. – Nitrate ion, NO3– present or ClO3– ion present. Ion nitrat, NO3– atau ion ClO3– hadir.
– Colourless gas. Gas tanpa warna. – Pass the gas through lime water, lime water turns chalky. Lalukan gas pada air kapur, air kapur menjadi keruh. – Draw the set-up of apparatus to conduct the test: Lukiskan susunan radas untuk menjalankan ujian:
– Produced by heating carbonate salt. Terhasil apabila garam karbonat dipanaskan. – Carbonate ion, CO3– present. Ion karbonat, CO3– hadir.
Calcium carbonate Heat Lime water
Ammonia, NH3 Ammonia, NH3
– Colourless gas with pungent smell. Gas tanpa warna dengan bau yang sengit. – Place a moist red litmus paper at the mouth of the boiling. tube, red litmus paper turns blue. Letakkan kertas litmus merah lembap pada mulut tabung didih, kertas litmus merah bertukar menjadi biru.
– Produced by heating ammonium salt with alkali. Terhasil apabila garam ammonium dipanaskan dengan alkali. – Ammonium ion NH4+ present. Ion ammonium NH4+ hadir.
Action of heat on nitrate and carbonate salts.
3
Kesan haba ke atas garam nitrat dan garam karbonat. Cation Kation
Nitrate (NO3–) / Nitrat ( NO3–) Decompose to oxygen gas and metal nitrite when heated Terurai kepada gas oksigen dan logam nitrit apabila dipanaskan
K+
m
2KNO2 + O2
2NaNO3
2NaNO2 + O2
White solid White solid Pepejal putih Pepejal putih
Does not decompose when heated Tidak diuraikan apabila dipanaskan
–
–
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Na+
2KNO3
White solid White solid Pepejal putih Pepejal putih
Carbonate (CO32–) / Karbonat (CO32–)
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Chemistry Form 4 • MODULE
Decompose to oxygen gas, nitrogen dioxide gas and metal oxide when heated Terurai kepada gas oksigen, gas nitrogen dioksida dan oksida logam apabila dipanaskan Ca2+
Mg2+
Al3+
Zn2+
2Ca(NO3)2
Decompose to carbon dioxide gas and metal oxide when heated Terurai kepada gas karbon dioksida dan oksida logam apabila dipanaskan CaCO3
2CaO + 4NO2 + O2
White solid White pepejal Brown fume Pepejal putih Pepejal putih Wasap perang 2Mg(NO3)2
MgCO3
2MgO + 4NO2 + O2
White solid White pepejal Brown fume Pepejal putih Pepejal putih Wasap perang 4Al(NO3 )3
CaO + CO2
White solid White solid Turn lime water chalky Pepejal putih Pepejal putih Air kapur menjadi keruh MgO + CO2
White solid White solid Turn lime water chalky Pepejal putih Pepejal putih Air kapur menjadi keruh 2Al2 (CO3)3
2Al2O3 + 12NO2 + O2
White solid White solid Turn lime water chalky Pepejal putih Pepejal putih Air kapur menjadi keruh
2Zn(NO3)2
ZnCO3
2ZnO + 4NO2 + O2
ZnO + CO2
White solid Yellow when hot Turn lime water chalky Pepejal white when cold Air kapur menjadi keruh Putih Kuning apabila panas,
White solid Yellow when hot Brown gas Pepejal white when cold Gas perang putih Kuning apabila panas, putih apabila sejuk
2Pb(NO3)2 Pb2+
putih apabila sejuk
2PbO + 4NO2 + O2
PbCO3 PbO + CO2 White solid Brown when hot Turn lime water chalky Pepejal Yellow when cold Air kapur menjadi keruh Putih Perang apabila panas,
White solid Brown when hot Brown fume Pepejal yellow when cold Wasap perang Putih Perang bila panas,
kuning apabila sejuk
kuning apabila sejuk
Cu2+
4
2Al2O3 + 6CO2
White solid White pepejal Brown fume Pepejal putih Pepejal putih Wasap perang
2Cu(NO3)2
2CuO + 4NO2 + O2
CuO + CO2 CuCO3 Green solid Black solid Turn lime water chalky Pepejal hijau Pepejal hitam Air kapur menjadi keruh
Blue solid Black solid Brown fume Pepejal biru Pepejal hitam Wasap perang
Sulphate salts are more stable, they are not easily decompose when heated. Garam sulfat lebih stabil kerana ia tidak terurai dengan mudah apabila dipanaskan.
5
Chloride salts do not decompose except NH4Cl: NH4Cl(s)
Garam klorida tidak terurai kecuali NH4Cl: NH4Cl(p) 6
NH3(g) + HCl(g)
NH3(g) + HCl(g)
Complete the following table: Lengkapkan jadual berikut: Observation Pemerhatian A white salt is heated.
Inference/conclusion Inferens/kesimpulan
Gas
Garam berwarna putih dipanaskan.
– Brown gas is released, the gas turns moist blue litmus paper red. Gas perang dibebaskan, menukar kertas litmus biru lembap kepada merah.
– Residue is yellow when hot and white when cold.
Garam berwarna hijau dipanaskan.
– Colourless gas released, the gas turns lime water chalky. Gelembung gas dibebaskan, ia menukar air kapur menjadi keruh.
– Residue is black
zinc
zinc nitrate
–
zink nitrat
karbon dioksida
– The residue is Baki ialah
kuprum(II)
– The green salt is Garam hijau ialah
Carbonate
dibebaskan. Ion
copper(II)
hadir.
.
.
Carbon dioxide gas released. Gas
hadir.
ion present. zink
oksida. Ion
– The white salt is Garam putih ialah
Zinc
oxide.
zink
Baki ialah
nitrat
dibebaskan. Ion
oxide.
Copper(II)
copper(II) carbonate
hadir.
ion present.
kuprum(II)
oksida. Ion
kuprum(II) karbonat
ion present karbonat
hadir.
.
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Baki berwarna hitam.
gas released. Nitrate ion present.
nitrogen dioksida
– The residue is
Baki berwarna kuning apabila panas dan putih apabila sejuk
A green salt is heated.
Nitrogen dioxide
–
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MODULE • Chemistry Form 4
A white salt is heated.
–
Garam berwarna putih dipanaskan.
Carbon dioxide Gas
– Colourless gas released, the gas turns lime water chalky.
Baki ialah
Baki berwarna perang apabila panas dan kuning apabila sejuk.
oksida. Ion
zinc zink
Baki ialah
– Residue is yellow when hot and white when cold.
Garam putih ialah
hadir.
. .
zinc
oxide.
ion present.
zink
zinc carbonate zink karbonat
hadir.
ion present.
plumbum(II)
oksida. Ion
– The white salt is
Gelembung gas dibebaskan, ia menukar air kapur menjadi keruh.
Lead(II)
plumbum(II) karbonat
Garam putih ialah
– The residue is
– Colourless gas released, the gas turns lime water chalky.
ion present karbonat
lead(II) carbonate
A white salt is heated. Garam berwarna putih dipanaskan.
oxide.
plumbum(II)
– The white salt is
– Residue is brown when hot and yellow when cold.
Carbonate
dibebaskan. Ion
lead(II)
– The residue is
Gelembung gas dibebaskan, ia menukar air kapur menjadi keruh.
gas released.
karbon dioksida
hadir.
. .
Baki berwarna kuning apabila panas dan putih apabila sejuk.
A blue salt is heated.
– Nitrogen dioxide gas released. Nitrate ion present.
Garam berwarna biru dipanaskan.
Gas nitrogen dioksida dibebaskan. Ion nitrat hadir.
– Brown gas is released, the gas turns moist blue litmus paper red.
– The residue is copper(II) oxide. Copper(II) ion present.
Gas perang terbebas menukar warna kertas limus biru menjadi merah.
– Residue is black.
Baki ialah kuprum(II) oksida. Ion kuprum(II) hadir.
– The blue salt is
Baki berwarna hitam.
A white salt is heated.
Garam biru ialah
copper(II) nitrate
.
kuprum(II) nitrat
.
– Nitrogen dioxide gas released. Nitrate ion present.
Garam berwarna putih dipanaskan.
Gas nitrogen dioksida dibebaskan. Ion nitrat hadir.
– Brown gas is released, the gas turns moist blue litmus paper red.
– The residue is lead(II) oxide. Lead(II) ion present.
Gas perang terbebas menukar warna kertas limus biru menjadi merah.
– Residue is brown when hot and yellow when cold. Baki berwarna perang apabila panas dan kuning apabila sejuk.
A white salt is heated.
Baki ialah plumbum(II) oksida. Ion plumbum(II) hadir.
– The blue salt is
lead(II) nitrate
plumbum(II) nitrat
Garam putih ialah
– Carbon dioxide gas released.
Garam berwarna putih dipanaskan.
– Colourles gas released, the gas turns lime water chalky. Gelembung gas dibebaskan, ia menukar air kapur menjadi keruh.
karbon dioksida
Gas
. .
Carbonate dibebaskan. Ion
ion present. karbonat
hadir.
– The possible residue are ZnO/PbO/MgO/Al2O3 Baki yang mungkin adalah CaOl/MgO/Al2O3.
– Residue is white Baki berwarna putih.
– From the above table, action of heat on heat on salt can be used to identify lead(II) nitrate , lead(II) carbonate , zinc nitrate , zinc carbonate , copper(II) nitrate and copper(II) carbonate . Daripada jadual di atas, kesan haba ke atas garam boleh digunakan untuk mengenal garam zink nitrat
,
zink karbonat
,
kuprum(II) nitrat
dan
plumbum(II) nitrat
kuprum(II) karbonat
, plumbum(II) karbonat ,
.
– Confirmatory test for other cations and anions is carried out by Confirmatory Tests for Anions and Cations Ujian pengesahan untuk kation dan anion lain boleh dijalankan dengan menggunakan Ujian Pengesahan Anion dan Kation. Confirmatory Tests for Cations Ujian Pengesahan bagi Kation
Chemical tests is conducted for confirmation of cations in aqueous form.
1
Ujian-ujian kimia dijalankan bagi pengesahan kation dalam bentuk akueus.
Confirmatory test is carried out by adding a small amount of sodium hydroxide solution / ammonia solution followed by excess sodium hydroxide / ammonia solution to the solution contains the cation.
2
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Ujian pengesahan dijalankan dengan menambah sedikit larutan natrium hidroksida / larutan ammonia diikuti dengan larutan natrium hidroksida / larutan ammonia berlebihan kepada larutan yang mengandungi kation.
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Chemistry Form 4 • MODULE
Sodium hydroxide solution Larutan natrium hidroksida
Cations Kation
small amount sedikit
K+ Na+ Ca2+
No change
No change
No change
Tiada perubahan
Tiada perubahan
Tiada perubahan
No change
No change
No change
No change
Tiada perubahan
Tiada perubahan
Tiada perubahan
Tiada perubahan
White precipitate
Insoluble in excess
No change
No change
Mendakan putih
Tak larut dalam berlebihan
Tiada perubahan
Tiada perubahan
Insoluble in excess
White precipitate
Soluble in excess
White precipitate
White precipitate
Soluble in excess
White precipitate
Soluble in excess
Mendakan putih
Larut dalam berlebihan
Mendakan putih
Larut dalam berlebihan
White precipitate
Soluble in excess
White precipitate
Soluble in excess
Mendakan putih
Larut dalam berlebihan
Mendakan putih
Larut dalam berlebihan
Green precipitate
Insoluble in excess
Green precipitate
Soluble in excess
Mendakan hijau
Tak larut dalam berlebihan
Mendakan hijau
Larut dalam berlebihan
Brown precipitate
Insoluble in excess
Brown precipitate
Soluble in excess
Mendakan perang
Tak larut dalam berlebihan
Mendakan perang
Larut dalam berlebihan
Blue precipitate
Insoluble in excess
Blue precipitate
Soluble in excess
Mendakan biru
Tak larut dalam berlebihan
Mendakan biru
Larut dalam berlebihan
Zn2+
White precipitate
Mendakan putih Mendakan putih
Fe2+ Fe3+ Cu2+ NH4+
excess berlebihan
No change
White precipitate
Pb2+
small amount sedikit
excess berlebihan
Tiada perubahan
Mg2+
Al3+
Ammonia solution Larutan ammonia
Tak larut dalam berlebihan
Mendakan putih
Larut dalam berlebihan
Insoluble in excess
Tak larut dalam berlebihan
Soluble in excess
Mendakan putih
Larut dalam berlebihan
No change
No change
No change
No change
Tiada perubahan
Tiada perubahan
Tiada perubahan
Tiada perubahan
(a) Reaction with small amount until excess of sodium hydroxide solution: (refer to the above table) Tindak balas dengan larutan natrium hidroksida sedikit demi sedikit sehingga berlebihan: (rujuk jadual di atas) Pungent smell, moist red litmus paper turn to blue Bau sengit, menukarkan kertas litmus merah lembap kepada biru
Solution contains: Larutan mengandungi:
Heat Add a little sodium hydroxide solution
K+, Ca2+, Mg2+, Al , Zn , Pb , 3+
2+
2+
Fe2+, Fe3+, Cu2+, NH4+
NH4+
Tambahkan sedikit larutan natrium hidroksida
K , NH4 +
Panaskan
+
No precipitate Tiada mendakan
No changes
K+
Tiada perubahan
Precipitate formed Mendakan terbentuk
Cu2+ (blue), Fe2+ (green), Fe3+ (brown)
Coloured precipitate Mendakan berwarna Add excess sodium hydroxide solution White precipitate Mendakan putih
Pb2+, Al3+, Zn2+, Ca2+, Mg2+
Soluble Larut
Tambahkan larutan natrium hidroksida berlebihan
Insoluble
Zn2+, Al3+, Pb2+
Ca2+, Mg2+
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MODULE • Chemistry Form 4
(b) Reaction with small amount until excess of ammonia solution: Tindak balas dengan larutan ammonia sedikit demi sedikit sehingga berlebihan:
Solution contains: Larutan mengandungi:
Add a little solution of ammonia Tambah sedikit larutan ammonia
No precipitate
Cu2+ (blue), Fe2+ (green), Fe3+ (brown)
Tiada mendakan
K+, Na+, Ca2+, Mg2+, Al3+, Zn2+, Pb2+, Fe2+, Fe3+, Cu2+
Add excess aqueous ammonia
Ca2+, K+, Na+
Precipitate formed Mendakan terbentuk
Tambahkan larutan ammonia berlebihan
Soluble Larut
Cu2+ Fe2+, Fe3+
Insoluble Coloured precipitate
Add excess aqueous ammonia
Mendakan berwarna
White precipitate Mendakan putih
Pb , Al , Zn2+, Mg2+ 2+
3+
Tambahkan larutan ammonia berlebihan
Tak larut
Soluble Larut
Insoluble
Zn2+ Mg2+, Al3+, Pb3+
Tak larut
(c) Conclusion of the confirmatory test for colourless/white cations: Kesimpulan ujian pengesahan bagi kation tanpa warna/putih:
(i) Zn2+: White precipitqte, soluble in excess of sodium hydroxide and ammonia solution (ii) Mg2+: White precipitate, insoluble in excess of sodium hydroxide and ammonia solution (iii) Al3+: White precipitate, soluble in excess of sodium hydroxide and insoluble in excess ammonia solution (iv) Ca2+: White precipitate insoluble in excess of sodium hydroxide and no precipitate with ammonia solution (v) NH4+: No precipitate with sodium hydroxide solution and pungent smell released when heated (d) Conclusion of the confirmatory test for coloured cations. Kesimpulan untuk ujian pengesahan bagi kation berwarna.
(i) Cu2+: Blue precipitate insoluble in excess of sodium hydroxide solution and soluble in excess ammonia solution (ii) Fe2+: Green precipitate, insoluble in excess of sodium hydroxide and ammonia solution (iii) Fe3+: Brown precipitate, insoluble in excess of sodium hydroxide and ammonia solution (e) All cations can be identified with confirmatory test using sodium hydroxide solution and ammonia solution except Al3+ and Pb2+. Semua kation boleh dikenal pasti dengan ujian pengesahan menggunakan larutan natrium hidroksida dan larutan ammonia kecuali Al3+ dan Pb2+.
(f) To differentiate between Al3+ and Pb2+: Untuk membezakan Al3+ dengan Pb2+:
– Al3+ and Pb2+ are differentiated by double decomposition reaction. An aqueous solution containing SO42–/ Cl–/ I– anion is used to detect the presence of Al3+ and Pb2+. Al3+ dan Pb2+ boleh dibezakan dengan menggunakan tindak balas pernguraian ganda dua. Larutan akueus yang mengandungi anion SO42–/ Cl– / I– digunakan untuk mengesan kehadiran Al3+ dan Pb2+.
– Precipitate is formed when solution containing SO42–/ Cl–/ I– added to Pb2+. Mendakan terbentuk apabila larutan mengandungi SO42–/ Cl–/ I– ditambah kepada Pb2+. – No precipitate when solution containing SO42–/ Cl– / I– added to Al3+.
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Tiada mendakan terbentuk apabila larutan mengandungi SO42–/ Cl–/ I– ditambah keepada Al3+.
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Chemistry Form 4 • MODULE
(g) Write the ionic equations for the formation of precipitates: Tuliskan persamaan ion bagi pembentukan mendakan:
Al3+ and Pb2+ Al3+ dan Pb2+
Add sodium sulphate solution
Add potassium iodide solution
Tambahkan larutan natrium sulfat
No changes
Add sodium chloride solution
White precipitate
Tiada perubahan
Mendakan putih
Pb2+ + SO42–
No changes Tiada perubahan
Tambahkan larutan natrium klorida
Pb2+
Al3+
Tambahkan larutan kalium iodida
Yellow precipitate Mendakan kuning
Pb2+
Al3+ Pb2+ + 2I–
PbSO4 No changes
PbI2
White precipitate
Tiada perubahan
Mendakan putih
Al3+
Pb2+ Pb2+ + 2Cl–
PbCl2
Confirmatory tests for Anions Ujian Pengesahan untuk Anion Anion/Anion
Procedure/Prosedur
Remark/Catatan
– 2 cm3 of dilute hydrochloric acid / nitric acid /sulphuric acid is added to 2 cm3 of carbonate salt. 2 cm3 asid nitrik/asid sulfurik cair ditambah kepada 2 cm3 garam karbonat.
– The gas given off is passed through lime water: Gas yang terbebas dilalukan air kapur.
Carbonate ion, CO32–
Draw a labelled diagram to conduct the test:
Ion karbonat, CO32–
Lukiskan gambar rajah berlabel untuk menjalankan ujian:
Acid Carbonate salt
Pembuakan berlaku dan air kapur menjadi keruh.
Inference: / Inferens: The gas is carbon dioxide. Gas tersebut ialah karbon dioksida.
Ionic equation: / Persamaan ion: H2O + CO2 CO32– + 2H+
Lime water
– 2 cm3 of dilute nitric acid is added to 2 cm3 solution of chloride ions followed by 2 cm3 of silver nitrate solution. 2 cm3 asid nitrik cair ditambah kepada 2 cm3 larutan ion klorida diikuti dengan 2 cm3 larutan argentum nitrat.
Chloride ion, Cl–
Observation: / Pemerhatian: Effervescence occurs and lime water turns chalky.
Ion klorida, Cl–
Observation: / Pemerhatian: A white precipitate is formed. Mendakan putih terbentuk.
Inference: / Inferens: The precipitate is silver chloride Mendakan ialah argentum klorida.
Ionic equation: / Persamaan ion: AgCl Ag+ + Cl– – 2 cm3 of dilute hydrochloric / nitric acid is added to 2 cm3 of sulphate solution followed by 2 cm3 of barium chloride solution / barium nitrate solution. Sulphate ion, SO4 Ion sulfat SO4
2–
2–
2 cm3 asid sulfurik asid/asid nitrik cair ditambah kepada 2 cm3 larutan sulfat diikuti dengan 2 cm3 larutan barium klorida/larutan barium nitrat.
Observation: / Pemerhatian: A white precipitate is formed. Mendakan putih terbentuk.
Inference: / Inferens: The precipitate is barium sulphate Mendakan tersebut ialah barium sulfat.
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Ionic equation: / Persamaan ion: BaSO4 Ba2+ + SO42–
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MODULE • Chemistry Form 4
– 2 cm3 of dilute sulphuric acid is added to 2 cm3 solution of nitrate ions followed by 2 cm3 of iron(II) sulphate solution. 2 cm3 larutan ion nitrat ditambah kepada 2 cm3 asid sulfurik cair diikuti dengan 2 cm3 larutan ferum(II) sulfat.
Nitrate ion, NO3
–
Ion nitrat, NO3–
– – –
The mixture is shaken. Campuran digoncang.
The test tube is slanted and held with a test tube holder.
Observation: / Pemerhatian: A brown ring is formed between two layers. Cincin perang terbentuk di antara dua lapisan.
Inference: / Inferens: Nitrate ion present. Ion nitrat hadir.
Tabung uji dicondongkan dan diapit dengan pemegang tabung uji.
A few drops of concentrated H2SO4 acid is dropped along the wall of the test tube and is held upright. Beberapa titis H2SO4 pekat dititiskan melalui dinding tabung uji dan ditegakkan.
EXERCISE / LATIHAN
(a) Substance A is white in colour. When A is strongly heated, a brown gas, B and gas C are released. These gases lighted a glowing wooden splinter. Residue D which is yellow in colour when hot and white when cold is formed.
1
Bahan A berwarna putih. Apabila A dipanaskan dengan kuat, gas berwarna perang B dan gas C dibebaskan. Gas C menyalakan kayu uji berbara. Baki D yang berwarna kuning apabila sejuk dan putih apabila sejuk terbentuk.
(i)
Name substances A, B, C and D. Namakan bahan A, B, C dan D.
A:
Zinc nitrate
B:
Nitrogen dioxide
C:
(ii) Write the chemical equation when substance A is heated. Tuliskan persamaan kimia apabila bahan A dipanaskan. 2Zn(NO3)2 2ZnO + 4NO2 + O2
Oxygen
D:
Zinc oxide
(b) Write the chemical equation when substance E is heated. Larutan tanpa warna E memberi keputusan berikut apabila dijalankan beberapa siri ujian:
S1 – Add sodium hydroxide solution, a white precipitate is formed. The precipitate is soluble in excess sodium hydroxide solution. L1 – Apabila ditambah dengan larutan natrium hidroksida, mendakan putih terbentuk. Mendakan ini larut apabila ditambah natrium hidroksida berlebihan.
S2 – Add ammonia solution, a white precipitate is formed. The precipitate is insoluble in excess ammonia solution. L2 – Apabila ditambah larutan ammonia, mendakan putih terbentuk dan mendakan ini tidak larut dalam larutan ammonia berlebihan.
S3 – Add potassium iodide solution, a yellow precipitate F, is formed. L3 – Apabila ditambah dengan larutan kalium iodida, mendakan kuning F terbentuk.
(i)
What are the possible cations present in substance E as a result of S1 test? Apakah kation-kation yang mungkin hadir dalam bahan E hasil ujian L1?
Pb2+, Al3+ and Zn2+
(ii) What are the possible cations present in solution E as a result from S1 and S2 tests? Apakah kation yang mungkin hadir dalam larutan E hasil ujian L1 dan L2? Pb2+ and Al3+
m
2+ Ion present /Ion hadir : Pb
Ionic equation/Persamaan ion : Pb2+ + 2I–
PbI2
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(iii) What is the ion present in E after S3 test has been done? Write an ionic equation for the formation of substance F. Apakah ion yang disahkan hadir dalam E setelah dilakukan ujian L3? Tulis persamaan ion bagi pembentukan bahan F.
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Chemistry Form 4 • MODULE
2
The diagram below shows the flow chart for Test I and Test II on colourless solution P. Rajah di bawah menunjukkan carta aliran bagi ujian I dan ujian II ke atas larutan tanpa warna P. Gas Q with a pungent smell is released and turns moist red litmus paper blue.
Test I Ujian I
Gas Q berbau sengit terbebas dan menukarkan warna kertas litmus merah lembap kepada biru.
Test II
Effervescence occurs and gas S is released
Colourless solution P
Ujian II
Larutan tanpa warna P
Add dilute hydrochloric acid
Pembuakan berlaku dan membebaskan gas S.
Tambah asid hidroklorik cair
(a) Identify gas Q and state its chemical properties. Kenal pasti gas Q dan nyatakan sifat kimia yang ditunjukkan oleh gas Q.
Ammonia, alkaline gas (b) State the reagent used in test I and state how the test is carried out. Nyatakan bahan uji yang digunakan dalam ujian I serta huraikan bagaimana ujian dilakukan.
Add sodium hydroxide solution, heat it. Name gas S and write the ionic equation that occurred in Test II:
(c) (i)
Namakan gas S dan tuliskan persamaan ion bagi tindak balas yang berlaku dalam ujian II:
Gas S/Gas S : Carbon dioxide
+ 2– Ionic equation/Persamaan ion: CO3 + 2H
H2O + CO2
(ii) Explain how you confirmed gas S. Terangkan bagaimana anda mengesahkan gas S.
Pass the gas through lime water, lime water turns chalky.
(iii) Name salt P based on the results of tests I and II. Namakan garam P berdasarkan keputusan ujian I dan II.
Ammonium carbonate 3
The table below shows the colour of five solutions labelled A, B, C, D and E added with small amount until excess of ammonia solution and sodium hydroxide solution. Jadual di bawah menunjukkan warna lima larutan berlabel A, B, C, D dan E yang ditambah dengan larutan natrium hidroksida dan larutan ammonia sedikit demi sedikit sehingga berlebihan. Solution
Colour
Larutan
With sodium hydroxide solution
Warna
A B C
Dengan larutan natrium hidroksida
With ammonia solution Dengan larutan ammonia
Blue
Blue precipitate insoluble in excess
Blue precipitate soluble in excess
Biru
Mendakan biru tidak larut dalam berlebihan
Mendakan biru larut dalam berlebihan
Colourless
White precipitate soluble in excess
White precipitate soluble in excess
Tanpa warna
Mendakan putih larut dalam berlebihan
Mendakan putih larut dalam berlebihan
Light green
Green precipitate
Dirty green precipitate
Hijau muda
Mendakan hijau kotor
Mendakan hijau kotor
D
Colourless
White precipitate soluble in excess
White precipitate insoluble in excess
Tanpa warna
Mendakan putih larut dalam berlebihan
Mendakan putih tidak larut dalam berlebihan
E
Colourless
White precipitate insoluble in excess
White precipitate insoluble in excess
Tanpa warna
Mendakan putih tidak larut dalam berlebihan
Mendakan putih tidak larut dalam berlebihan
(a) What are the cations present in Apakah kation yang terdapat dalam A: Cu
2+
2+ B: Zn
2+ C: Fe
2+ E: Mg
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MODULE • Chemistry Form 4
(b) State another test to identify C. Nyatakan satu lagi ujian bagi mengenali C.
Add potassium hexacyanoferrate(II) solution, light blue precipitate formed (c) What are the possible cations present in solution D? Apakah kation-kation yang mungkin terdapat dalam larutan D?
Al3+, Pb2+ (d) Describe briefly a test that can differentiate the cations present in solution D. Terangkan secara ringkas satu ujian yang boleh digunakan untuk membezakan kation-kation yang hadir dalam larutan D.
– Add a few drops of potassium iodide / sodium chloride / sodium sulpahte solution into 1 cm3 of solution D. – Yellow/white precipitate formed, lead(II) ion / Pb2+ present – No precipitate, aluminium ion / Al3+ present. You are given lead(II) carbonate, zinc(II) carbonate and copper(II) carbonate. Without using any reagents, describe how you can differentiate the three substances in the laboratory.
4
Anda diberi plumbum(II) karbonat, zink(II) karbonat dan kuprum(II) karbonat. Tanpa menggunakan sebarang bahan uji, terangkan bagaimana anda membezakan ketiga-tiga bahan tersebut di dalam makmal.
•
Heat
strongly
kuat
Panaskan dengan bakinya:
boiling tube
one spatula of each salt in a
satu spatula setiap jenis garam dalam
and observe the residue: tabung didih
dan perhatikan baki-
– If the residue is yellow when hot and white when cold, then zinc oxide is formed. The salt is zinc carbonate . Jika baki berwarna kuning apabila panas dan putih apabila sejuk, maka zink karbonat . adalah
– If the residue is black, then
copper(II) oxide
Jika baki berwarna hitam, maka
zink oksida
terbentuk. Garam tersebut
is formed. The salt is copper(II) carbonate .
kuprum(II) oksida
kuprum(II) karbonat
terbentuk. Garam tersebut adalah
– If the residue is brown when hot and yellow when cold, then lead(II) carbonate . Jika baki berwarna perang apabila panas dan kuning apabila sejuk, maka plumbum(II) karbonat . tersebut adalah
lead(II) oxide
.
formed. The salt is
plumbum(II) oksida
terbentuk. Garam
The diagram below shows the flow chart of changes that took place beginning from solid M. Solid M is a zinc salt. When solid M is heated strongly, it decomposes into solid Q which is yellow when hot and white when cold.
5
Rajah di bawah menunjukkan carta aliran bagi perubahan yang berlaku bermula daripada pepejal M. Pepejal M adalah suatu garam bagi zink. Apabila pepejal M dipanaskan dengan kuat, ia terurai kepada suatu pepejal Q yang berwarna kuning apabila panas dan putih apabila sejuk. Reaction I Tindak balas I
Solid M Pepejal M
Reaction II Tindak balas II
Add dilute nitric acid/Tambah asid nitrik cair
Panaskan Heat
Solid Q + carbon dioxide gas Pepejal Q + gas karbon dioksida
Solution S Larutan S
+
Carbon dioxide gas Gas karbon dioksida
+
Water Air
Reaction III + Magnesium Tindak balas III + Magnesium
Zinc metal + Magnesium nitrate solution / Logam zink + Larutan magnesium nitrat
(a) (i)
Berikan satu ujian kimia bagi gas karbon dioksida.
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Passed the gas through lime water, lime water turns chalky
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Chemistry Form 4 • MODULE
(ii) Draw a diagram of the apparatus set-up to carry out reaction I. Lukiskan gambar rajah susunan radas untuk menjalankan tindak balas I. Solid M Heat
Lime water
(b) Name solids M and Q. Nyatakan nama pepejal M dan Q.
M : Zinc carbonate
Q: Zinc oxide
(c) State the observations made when excess ammonia solution is added to solution S. Nyatakan pemerhatian yang dibuat apabila larutan ammonia berlebihan ditambahkan kepada larutan S.
White precipitate, soluble in excess of ammonia solution (d) (i)
Write the chemical equation for reaction II. Tuliskan persamaan kimia bagi tindak balas II.
ZnCO3 + 2HNO3
Zn(NO3)2 + H2O + CO2
(ii) For reaction II, calculate the volume of carbon dioxide gas released at room condition if 12.5 g solid M decomposes completely. [Relative atomic mass: C =12, O =16, Zn = 65, 1 mole of gas occupies 24 dm3 at room condition] Bagi tindak balas II, hitungkan isi padu gas karbon dioksida yang dibebaskan pada keadaan bilik, jika 12.5 g pepejal M terurai dengan lengkap. [Jisim atom relatif: C = 12, O = 16, Zn = 65, 1 mol gas menempati 24 dm3 pada suhu bilik]
12.5 = 0.1 mol 125 From the equation, 1 mol M : 1 mol CO2 0.1 mol M : 0.1 mol CO2 Volume of CO2 = 0.1 mol × 24 dm3 mol–1 = 2.4 dm3 Mol of solid M =
(e) Name reaction III. Namakan tindak balas III.
Displacement reaction (f) Describe a chemical test to determine the presence of anion in the magnesium nitrate solution. Huraikan ujian kimia untuk menentukan kehadiran anion dalam larutan magnesium nitrat.
– About Masukkan
2
cm3 of magnesium nitrate solution is poured into a test tube.
2
cm3 larutan magnesium nitrat ke dalam tabung uji.
– 2 cm3 of dilute sulphuric acid is added to the solution followed by 2 cm3 of 2 cm
asid sulfurik
3
shaken
– The mixture is Campuran
digoncang
– The test tube is Tabung uji
cair ditambah kepada larutan diikuti dengan larutan
iron(II) sulphate
ferum(II) sulfat
solution.
.
. .
slanted
and held with a test tube holder.
dicondongkan
dan dipegang dengan pemegang tabung uji.
– A few drops of concentrated sulphuric acid is dropped along the wall of the test tube and is held upright. pekat
Beberapa titis asid sulfurik
– A
dititiskan melalui dinding tabung uji dan ditegakkan.
brown ring is formed between two layers. Gelang perang
– Anion present is
terbentuk antara dua lapisan.
nitrate
ion.
nitrat
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MODULE • Chemistry Form 4
The diagram below shows list of chemical substances.
6
Rajah di bawah menunjukkan senarai bahan-bahan kimia. Hydrochloric acid, 1.0 mol dm–3
Barium chloride solution, 1.0 mol dm–3
Larutan asid hidroklorik, 1.0 mol dm
Larutan barium klorida, 1.0 mol dm–3
Iron(II) sulphate solution, 1.0 mol dm–3
Solid copper(II) oxide
Solid calcium carbonate
Larutan ferum(II) sulfat, 1.0 mol dm–3
Pepejal kuprum(II) oksida
Pepejal kalsium karbonat
–3
(a) (i)
Choose two solutions that can be used to prepare insoluble salts. Pilih dua larutan yang digunakan untuk menyediakan garam tak terlarutkan.
Barium chloride and iron(II) sulpahate
(ii) What is the type of reaction for the preparation of the salt in (a)(i)? Apakah jenis tindak balas bagi penyediaan garam di (a)(i)?
Double decomposition reaction
(iii) Write the ionic equation for the production of the salt in (a)(i). Tulis persamaan ion bagi penghasilan garam di (a)(i).
Ba2+ + SO42–
BaSO4
(iv) Describe how to collect the pure salt produced. Huraikan bagaimana anda mendapatkan pepejal garam tulen yang terhasil.
Filter the mixture and rinse with distilled water (b) State the observations when sodium hydroxide solution is added in small amount until in excess into iron(II) sulphate solution./ Nyatakan pemerhatian anda apabila larutan natrium hidroksida ditambah sedikit sehingga berlebihan kepada larutan ferum(II) sulfat.
Green precipitate formed, insoluble in excess of sodium hydroxide solution (c) (i)
Choose two chemical substances that can react to produce carbon dioxide gas. Pilih dua bahan yang boleh bertindak balas untuk menghasilkan gas karbon dioksida.
Calcium carbonate and hydrochloric acid
(ii) Write a balanced chemical equation for the reaction in (c)(i). Tulis persamaan kimia seimbang bagi tindak balas di (c)(i).
CaCO3 + 2HCl
CaCl2 + H2O + CO2
You are given zinc chloride crystals. Describe how you would conduct a chemical test in the laboratory to identify the ions presence ions in zinc chloride crystals./ Anda diberi hablur zink klorida. Huraikan bagaimana anda boleh menjalankan ujian kimia di
7
dalam makmal untuk mengenal pasti ion-ion yang hadir dalam hablur zink klorida.
Dissolve
–
1 spatula zinc chloride crystals in 10 cm3 of 2
distilled
water.
1 spatula hablur zink klorida di dalam 10 cm3 air suling . 2 Larutan solution is poured in three test tubes./ tersebut dituang ke dalam tiga tabung uji.
Larutkan
– The
– Add a few drops sodium hydroxide solution are added to zinc chloride precipitate soluble in excess of sodium hydroxide solution. natrium hidroksida Tambahkan beberapa titik larutan ke dalam Mendakan putih natrium hidroksida larut dalam larutan
larutan
solution
until excess. A white
zink klorida sehingga
berlebihan
.
berlebihan.
ammonia solution solution are added to another zinc chloride until excess. A white – Add a few drops excess ammonia zinc ions precipitate soluble in of solution. Ions present are . ammonia Tambahkan beberapa titik larutan Mendakan putih larut dalam larutan
ke dalam ammonia
larutan
zink klorida yang lain sehingga ion zink berlebihan. Ion yang hadir adalah
berlebihan
.
.
nitric acid is added to 2 cm3 solution of chloride ions followed by 2 cm3 of silver nitrate – About 2 cm3 of dilute solution. White precipitate formed. Ions present are chloride ions.
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asid nitrik 2 cm3 cair ditambahkan kepada 2 cm3 larutan ion klorida diikuti dengan 2 cm3 larutan Mendakan putih terbentuk. Ion yang hadir adalah ion klorida.
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Chemistry Form 4 • MODULE
8
The diagram below shows the formation of zinc nitrate and the changes to other compounds. Rajah berikut menunjukkan pembentukan zink nitrat dan perubahannya kepada sebatian lain. Heat
+ Substance X Zinc oxide
+ Bahan X
Zink oksida
Panaskan
Zinc nitrate Zink nitrat
Brown gas Gas perang
+ Potassium carbonate solution/ + Larutan kalium karbonat Precipitate Z + Potassium nitrate Mendakan Z
(a) (i)
Kalium nitrat
Zinc oxide reacts with substance X to form zinc nitrate. State the name of substance X. Zink oksida bertindak balas dengan bahan X untuk membentuk zink nitrat. Namakan sebatian X.
Nitric acid
(ii) Write the chemical equation for the reaction in (a)(i). Tuliskan persamaan kimia untuk tindak balas dalam (a)(i).
(b) (i)
ZnO + HNO3 → Zn(NO3)2 + H2O State the name of the brown gas formed. Namakan gas perang yang terbentuk.
Nitrogen dioxide
(ii) Write the chemical equation for the reaction in (b)(i). Tuliskan persamaan kimia untuk tindak balas dalam (b)(i).
2Zn(NO3)2 → 2ZnO + 2NO2 + O2 (c) When potassium carbonate solution added to zinc nitrate solution, precipitate Z and potassium nitrate formed. Apabila larutan kalium karbonat ditambah kepada larutan zink nitrat, mendakan Z dan kalium nitrat terbentuk.
(i)
State the type of reaction occurs. Namakan jenis tindak balas yang berlaku.
Precipitation
(ii) Write the ionic equation for the formation of compound Z. Tulis persamaan ion untuk pembentukan sebatian Z.
Zn2+ + CO32– → ZnCO3
(iii) State how the precipitate Z separated from potassium nitrate. Nyatakan bagaimana mendakan Z diasingkan daripada kalium nitrat.
Filtration
(d) Excess of zinc nitrate solution is added to 100 cm3 of 1 mol dm–3 potassium carbonate. Calculate the mass of zinc carbonate formed. [Relative atomic mass: Zn = 65, C = 12, O = 16] Larutan zink nitrat berlebihan ditambah kepada 100 cm3 larutan kalium karbonat 1 mol dm–3. Hitungkan jisim zink karbonat yang terbentuk. [Jisim atom relatif: Zn = 65, C = 12, O = 16]
Zn(NO3)2 + K2CO3 → ZnCO3 + 2KNO3 100 Mol of K2CO3 = 1× = 0.1 mol 1 000 From the equation, 1 mol K2CO3 : 1 mol ZnCO3 0.1 mol K2CO3 : 0.1 mol ZnCO3 Mass of ZnCO3 = 0.1 mol × 125 g mol–1 = 12.5 g
(e) Sodium hydroxide solution is added until excess to zinc nitrate solution. State the observation that can be made. Larutan natrium hidroksida ditambah sedikit demi sedikit hingga berlebihan kepada larutan zink nitrat. Nyatakan pemerhatian yang dapat dibuat.
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White precipitate soluble in excess of sodium hydroxide solution.
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MODULE • Chemistry Form 4
Objective Questions / Soalan Objektif Which of the following is a salt?
1
5
Antara berikut, yang manakah adalah garam? A Lead(II) oxide Plumbum(II) oksida B Calcium hydroxide Kalsium hidroksida C Barium sulphate Barium sulfat D Tetrachloromethane Tetraklorometana
Antara tindak balas berikut, yang manakah akan menghasilkan kuprum(II) klorida?
I
Kuprum dan asid hidroklorik Kuprum(II) oksida dan asid hidroklorik
III Copper(II) carbonate and hydrochloric acid Kuprum(II) karbonat dan asid hidroklorik
IV Copper(II) sulphate and sodium chloride Kuprum(II) sulfat dan natrium klorida
Antara garam berikut, yang manakah larut dalam air? A Iron(II) sulphate Ferum(II) sulfat B Silver chloride Argentum klorida C Calcium carbonate Kalsium karbonat D Lead(II) bromide Plumbum(II) bromida
Which of the following salts can be prepared by double decomposition reaction?
3
Antara garam berikut, yang manakah boleh disediakan dengan kaedah pemendakan? A Copper(II) chloride Kuprum(II) klorida B Lead(II) nitrate Plumbum(II) nitrat C Barium sulphate Barium sulfat D Zinc sulphate Zink sulfat
Which pair of substances represented by the following formulae react to produce salt?
4
Antara pasangan bahan tindak balas berikut, yang manakah dapat bertindak balas menghasilkan garam?
I II III IV
HNO3(aq) + NaOH(aq) HCl(aq) + NaCl(aq) H2SO4(aq) + MgSO4(aq) H2CO3(aq) + KOH(aq) A I and II only I dan II sahaja B
I and IV only
C
I, II and IV only
I dan IV sahaja I, II dan IV sahaja
D
I, II, III and IV
m
A
I and II only
B
II and III only
C
III and IV only
D
I, II, III and IV
I dan II sahaja II dan III sahaja III dan IV sahaja I, II, III dan IV
6
If 0.2 mole of calcium carbonate is heated until no further change, what is the mass of calcium oxide produced? [Relative atomic mass of C=12, O=16, Ca=40] Jika 0.2 mol kalsium karbonat dipanaskan sehingga tiada perubahan, berapakah jisim kalsium oksida, CaO yang terhasil? [Jisim atom relatif: C = 12, O = 16, Ca = 40] A 5.6 g B 11.2 g C 16.8 g D 22.4 g
7
The diagram below shows observations when white solid X heated strongly. Rajah di bawah menunjukkan pemerhatian apabila pepejal X dipanaskan dengan kuat. White solid X / Pepejal putih X Heat strongly/Panaskan dengan kuat – Brown gas is released/ Gas perang terbebas – Residue is a solid which is yellow when hot and white when cold/ Baki perang apabila panas dan kuning apabila sejuk.
Which of the following substance is X? Antara berikut, yang manakah adalah bahan X? A Zinc nitrate Zink nitrat B Zinc carbonate Zink karbonat C Lead(II) nitrate Plumbum(II) nitrat D Lead(II) carbonate Plumbum(II) karbonat
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I, II, III dan IV
Copper and hydrochloric acid
II Copper(II) oxide and hydrochloric acid
Which of the following salts is soluble in water?
2
Which of the following reactions will produce copper(II) chloride?
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Chemistry Form 4 • MODULE
8
The diagram below shows a series of tests carried out on solution Y. Rajah di bawah menunjukkan satu siri ujian kimia ke atas larutan Y. Solution Larutan
Y
Sodium hydroxide solution
Green precipitate
Larutan natrium hidroksida
Mendakan hijau
10 The diagram below shows the reaction between 20 cm3 of 0.5 moldm–3 of sodium chloride solution is and to 20 cm3 of 1.0 moldm–3 silver to produce silver chloride precipitate and solution X. Rajah di bawah menunjukkan tindak balas antara 20 cm3 larutan natrium klorida 0.5 mol dm–3 dengan 20 cm3 larutan argentum nitrat 1.0 mol dm–3 untuk menghasilkan mendakan argentum klorida dan larutan X. 20 cm3 of 1.0 moldm–3 silver nitrate solution
Dilute nitric acid followed by silver nitrate solution
20 cm3 argentum nitrat 1.0 mol dm–3
Asid nitrik cair diikuti dengan larutan argentum nitrat
White precipitate/Mendakan putih
Which of the following is solution Y? Antara berikut, yang manakah adalah bahan Y? A Iron(II) chloride C Copper(II) chloride Ferum(II) klorida Kuprum(II) klorida B Iron(II) sulphate D Copper(II) carbonate Ferum(II) sulfat Kuprum(II) karbonat
9
The diagram below shows two bottles of aqueous solutions. Rajah di bawah menunjukkan dua botol mengandungi larutan garam aluminium nitrat dan larutan plumbum(II) nitrat.
20 cm3 of 0.5 moldm–3 of sodium chloride solution 20 cm3 larutan natrium klorida 0.5 mol dm–3
Solution X Larutan X
Silver chloride precipitate Mendakan argentum klorida
Which of the following ions are present in the solution X? Antara ion berikut, yang manakah yang hadir dalam larutan X?
Aluminium nitrate solution Larutan aluminium nitrat
Lead(II) nitrate solution Larutan plumbum(II) nitrat
Which of the following substances can be used to differentiate between and aluminium nitrate solution and lead(II) nitrate solution? Antara bahan berikut, yang manakah dapat digunakan untuk membezakan larutan aluminium nitrat dan larutan plumbum(II) nitrat?
A
Sodium hydroxide solution
B
Ammonia solution
C
Potassium chloride solution
D
Barium nitrate solution
I II III IV
Na+ Ag+ NO3– Cl– A I and III only I dan III sahaja B
II and III only
C
I, II and III only
D
I, II, and IV only
II dan III sahaja I, II dan III sahaja I, II dan IV sahaja
Larutan natrium hidroksida Larutan ammonia Larutan kalium klorida
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Larutan barium nitrat
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MODULE • Chemistry Form 4
8
MANUFACTURED SUBSTANCES IN INDUSTRY BAHAN KIMIA DALAM INDUSTRI
• SULPHURIC ACID/ASID SULFURIK – Write an equation for Contact process and Haber process, stating the temperature, pressure and catalyst required. Menulis persamaan untuk Proses Sentuh dan Proses Haber, menyatakan suhu, tekanan dan mangkin yang diperlukan.
• AMMONIA/AMMONIA – List the uses of sulphuric acid and ammonia. Menyenaraikan kegunaan asid sulfurik dan ammonia.
– Explain how sulphur dioxide causes environmental pollution. Menerangkan bagaimana sulfur dioksida menyebabkan pencemaran alam.
• – – – –
ALLOY/ALOI State the meaning of an alloy. / Menyatakan maksud aloi. Draw the arrangement of atoms in metals and alloys. / Melukis susunan atom di dalam aloi dan logam. Explain why an alloy is stronger than its pure metal. / Menerangkan mengapa aloi lebih kuat daripada logam tulennya. Design an experiment to investigate the hardness of a material and its alloy. Mereka bentuk eksperimen untuk mengkaji kekerasan aloi dan logam tulennya.
– List the examples of alloys, compositions and properties of alloys. / Menyenaraikan contoh aloi, komposisi dan sifat aloi. – Relate properties of alloys to their uses. / Mengaitkan sifat aloi dengan kegunaannya.
• – – – –
POLYMERS/POLIMER Sate the meaning of polymers. / Menyatakan maksud polimer. List naturally occurring polymers and synthetic polymers. / Menyenaraikan polimer semula jadi dan polimer sintetik. State the uses of synthetic polymers. / Menyatakan kegunaan polimer sintetik. Explain the effect of environmental pollution caused by the disposal of synthetic polymers. Menghuraikan kesan pembuangan polimer sintetik ke atas pencemaran alam sekitar.
– Ways to reduce pollution caused by synthetic polymers. / Cara-cara mengurangkan pencemaran yang disebabkan polimer sintetik.
• – – –
GLASS AND CERAMICS/KACA DAN SERAMIK List uses of glass and ceramics. / Menyenaraikan kegunaan kaca dan seramik. List types of glass and their properties. / Menyenaraikan jenis-jenis kaca dan kegunaannya. State properties of ceramics. / Menyenaraikan sifat-sifat seramik.
• COMPOSITE MATERIALS/BAHAN KOMPOSIT – State the meaning of composite materials. / Menyatakan maksud bahan komposit. – List examples of composite materials and their components and uses. Menyenaraikan contoh-contoh bahan komposit dan komponen dan kegunaannya.
– Compare and contrast properties of composite materials with those of their original component Membanding dan membezakan sifat bahan komposit dengan bahan asalnya.
– Design an experiment to produce composite materials.
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Chemistry Form 4 • MODULE
Sulphuric Acid / Asid Sulfurik 1
Sulfuric acid is manufactured through the Contact Process. This process consists of three stages. Asid sulfurik dihasilkan melalui Proses Sentuh. Proses ini terdiri daripada tiga peringkat. Sulphur Sulfur
Sulphur dioxide SO2
Sulphur trioxide SO3
Oxygen
Sulfur dioksida SO2
Sulfur trioksida SO3
Oleum H 2 S2 O7
Asid sulfurik H2SO4
Oleum H2 S2 O7
Oksigen
Stage I/Peringkat I
Sulphuric acid H2SO4
Stage II/Peringkat II
Stage III/Peringkat III Concentrated sulphuric acid Asid sulfurik pekat
Waste gas Gas terbuang
Molten sulphur Sulfur lebur
SO3
Dry air Udara kering
Burner Pembakar
SO2 + O2
H2S2O7 (Oleum)
Catalytic converter Bekas mangkin
H2S2O7 (Oleum)
Water/Air H2SO4
Stage I/Peringkat I 2
Stage II/Peringkat II
Stage III/Peringkat III
Based on the above diagram, explain each stage and state the conditions required. Include all the balanced chemical equations involve in each stage. Berdasarkan rajah di atas, terangkan setiap peringkat serta keadaan yang diperlukan. Sertakan semua persamaan kimia yang seimbang yang terlibat dalam setiap peringkat. Stage
Explanation/Equation
Peringkat
Stage I: / Peringkat I: Production of sulphur dioxide Penghasilan
sulfur dioksida
Stage II: / Peringkat II: Production of sulphur trioxide Penghasilan
sulfur trioksida
Penerangan/Persamaan kimia
– Molten sulphur is burnt in dry air to produce sulphur dioxide. Sulfur lebur dibakar dalam udara kering untuk menghasilkan sulfur dioksida. Balanced equation: / Persamaan seimbang:
S + O2
SO2
– In a converter, sulphur dioxide and excess oxygen are passed through vanadium(V) oxide . Di dalam bekas mangkin, sulfur dioksida dan oksigen dialirkan melalui Balanced equation: / Persamaan seimbang:
2SO2 + O2
vanadium(V) oksida
.
2SO3
– Optimum conditions for maximum amount of product are: Keadaan optimum untuk penghasilan sulfur trioksida yang maksimum adalah:
Temperature / Suhu:
450 – 500 °C 2 – 3 atm
Catalyst / Mangkin:
vanadium(V) oxide, V2O5
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Pressure / Tekanan:
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MODULE • Chemistry Form 4
Stage III: / Peringkat III: sulphuric acid Production of Penghasilan
–
Sulphur trioxide Sulfur trioksida
asid sulfurik
is dissolved in concentrated sulphuric acid to form oleum.
Balanced equation: / Persamaan seimbang:
SO3 + H2SO4
Oleum
–
Oleum
.
H2S2O7
is diluted in water to produce concentrated sulphuric acid. asid sulfurik pekat
dilarutkan dalam air untuk menghasilkan
Balanced equation: / Persamaan seimbang:
H2O + H2S2O7
*
oleum
dilarutkan dalam asid sulfurik pekat untuk menghasilkan
.
2H2SO4
Note that directly dissolving SO3 in water is impractical due to the highly exothermic nature of the reaction. Acidic vapour or mists are formed instead of a liquid.
Melarutkan sulfur dioksida dalam air secara terus tidak dapat dilakukan kerana pembebasan haba yang sangat banyak. Ini kerana tindak balas tersebut adalah eksotermik. Asid yang terhasil adalah dalam bentuk wap air dan bukannya cecair.
State five main uses of sulphuric acid.
3
Nyatakan lima kegunaan utama asid sulfurik.
(i) To manufacture detergents
(iv) As electrolyte in car batteries
(ii) To manufacture fertilizers
(v) To manufacture synthtetic fibers
(iii) To manufacture paints
Sulphur dioxide and environmental pollution:
4
Sulfur dioksida dan pencemaran alam:
(a) Major sources of sulphur dioxide in the air is combustion of fuel in power station or factories. Punca utama kehadiran sulfur dioksida di udara adalah pembakaran bahan bakar di stesen janakuasa dan kilang.
(b) Sulphur dioxide dissolve in rainwater to form sulphurous acid which will cause acid rain, balanced equation: Sulfur dioksida larut dalam air hujan untuk membentuk asid sulfurus yang menghasilkan hujan asid, persamaan seimbang:
SO2 + H2O
H2SO3
Oxidation of sulphurous acid in the air will produce sulphuric acid which will also cause acid rain. Pengoksidaan asid sulfurus di udara akan menghasilkan asid sulfurik yang juga merupakan penyebab kepada hujan asid.
(c) Effect of acid rain: Kesan hujan asid:
corrodes building, monuments and statues made from marble (calcium carbonate) because – Acid rain calcium carbonate react with acid to produce salt, water and carbon dioxide, balanced equation: mengkakis Hujan asid bangunan, monumen dan tugu yang diperbuat daripada marmar (kalsium karbonat) kerana kalsium karbonat bertindak balas dengan asid menghasilkan garam, air dan karbon dioksida, persamaan seimbang:
CaCO3 + H2SO4
CaSO4 + H2O + CO2
corrodes structures of the buildings or bridges which are made from – Acid rain iron rusts faster with the presence of sulphuric acid.
metal
. The
mengkakis Hujan asid struktur bangunan-bangunan dan jambatan-jambatan yang diperbuat daripada logam. Besi berkarat lebih cepat dengan kehadiran asid sulfurik.
– Acid rain Hujan asid
– Acid rain Hujan asid
increases
the acidity of lakes and river that causes aquatic organism to die.
meningkatkan
increases
keasidan tasik-tasik dan sungai-sungai yang menyebabkan kematian hidupan akuatik.
the acidity of soil. Acidic soil is not suitable for the growth of plants.
meningkatkan
keasidan tanah. Tanah yang berasid tidak sesuai untuk pertumbuhan tanam-tanaman.
(d) Ways to reduce production of sulphur dioxide and effect of acid rain: Cara-cara mengurangkan penghasilan sulfur dioksida dan kesan-kesan hujan asid:
– Gas released from power station and factories are sprayed with powdered limestone ( calcium carbonate ). Gas yang dilepaskan dari stesen janakuasa dan kilang boleh disembur dengan serbuk batu kapur (
– Add lime (
calcium oxide
m
).
) and limestone ( calcium carbonate ) to the lake or river.
kalsium oksida
) dan batu kapur (
kalsium karbonat
) ke tasik atau sungai.
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kalsium karbonat
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Chemistry Form 4 • MODULE
Ammonia / Ammonia 1
In industry, ammonia is manufactured through the Haber Process: Dalam industri, ammonia dihasilkan melalui Proses Haber.
N2 + 3H2
Balanced equation of reaction / Persamaan seimbang tindak balas: Ferum
400 – 500°C
Catalyst / Mangkin : Temperature / Suhu : Pressure / Tekanan : 2
2NH3
200 atm
Ammonia is used in the manufacture of: Ammonia digunakan dalam pembuatan:
(a) Synthetic fertilizer such as ammonium sulphate, ammonium nitrate, ammonium phosphate and urea Baja sintetik seperti ammonium sulfat, ammonium nitrat, ammonium fosfat dan urea.
(b) Nitric acid in Ostwald Process. Asid nitrik dalam Proses Ostwald.
(c) Synthetic fiber and nylon. Gentian kaca sintetik dan nilon.
(d) Liquid form of ammonia is used as cooling agent in refrigerators. Cecair ammonia digunakan sebagai penyejuk dalam peti sejuk.
(e) Prevent coagulation of latex. Mencegah penggumpalan lateks. 3
Ammonia is a colourless gas with pungent smell and very soluble in water. Ammonia adalah gas yang tidak berwarna dengan bau yang sengit dan sangat larut di dalam air.
4
Chemical properties of ammonia: Sifat-sifat kimia ammonia: Property Sifat
Dissolve in water to form weak alkali Larut di dalam air membentuk alkali lemah
Effect on moist red litmus paper Kesan ke atas kertas litmus merah
Neutralise any acid to form ammonium salt Meneutralkan asid untuk membentuk garam ammonium
Chemical equation / Observation Persamaan kimia / Pemerhatian
NH3(g) + H2O(ce)
NH4+(ak) + OH –(ak)
The presence of hydroxide ions causes aqueous solution of ammonia to become alkaline. Kehadiran ion hidroksida menyebabkan larutan ammonia akueus menjadi alkali.
Turn moist red litmus paper to blue Ammonia reacts with sulphuric acid to form ammonium sulphate salt. Ammonia bertindak balas dengan asid sulfurik untuk membentuk garam ammonium sulfat. Balanced equation: / Persamaan seimbang:
2NH3 + H2SO4
(NH4)2SO4
Alloy / Aloi 1
Complete the following table: Lengkapkan jadual di bawah: Questions Soalan
1 What is the meaning of alloy? Apakah maksud aloi?
Facts / Elaboration / Drawing Fakta / Penerangan / Lukisan
mixture elements of two or more with a certain Alloy is a fixed/specific composition. The major component in the mixture is a metal. tetap
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campuran unsur dua atau lebih dengan komposisi yang Aloi ialah logam Komponen utama dalam campuran tersebut ialah .
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MODULE • Chemistry Form 4
2 Relate the arrangement of atoms in pure metals to their ductile and malleable properties. Nyatakan hubungan antara susunan atom dalam logam tulen dengan sifat mulur dan mudah ditempa.
Force/Daya
Pure metals/Logam tulen atoms
.
Pure metal is made up of one type of
atom
Logam tulen terbentuk daripada satu jenis
Atoms in pure metals are all the same The same
size
layers saiz
Atom-atom dalam logam tulen mempunyai
.
. yang sama.
atoms are orderly arranged in layers. saiz
Atom-atom yang mempunyai
lapisan
yang sama ini tersusun dalam
force is applied to the pure metal, layers of atoms When easily over one another. daya Apabila sama lain.
3 Draw the arrangement of atoms in Lukiskan susunan atom dalam
(a) (b)
dikenakan ke atas logam tulen, lapisan atom
menggelongsor
.
slide
di antara satu
(b) Steel / Keluli
(a) Bronze / Gangsa
Bronze (90% copper and 10% tin) Gangsa (90% kuprum dan 10% timah)
Carbon
Steel (99% iron and 1% of carbon) Keluli (99% besi dan 1% karbon)
[Relative atomic mass: Cu = 64, Sn = 119, Fe = 56; C = 12] [Jisim atom relatif: Cu = 64, Sn = 119, Fe = 56, C = 12]
4 Explain why an alloy is stronger than its pure metal in terms of the arrangement of atoms in metals and alloys. Terangkan mengapa aloi lebih kuat daripada logam tulen dari segi susunan atom dalam logam dan aloi.
Iron
Copper
Tin
Atoms of other element added to the pure metal to make an alloy are different in size. Atom-atom unsur lain yang ditambah dalam logam tulen membentuk aloi yang terdiri daripada atom-atom berlainan saiz. yang
These atoms Atom-atom ini
disrupts
the orderly arrangement of atoms in pure metal.
mengganggu
susunan atom yang teratur dalam logam tulen.
force is applied to an alloy, the presence of added other atoms When prevent layers of atoms from sliding . daya dikenakan ke atas aloi, kehadiran atom-atom asing ini Apabila menggelongsor atom-atom ini daripada .
5 State three reason why pure metals are alloyed before used. Nyatakan tiga sebab mengapa logam tulen dialoikan sebelum digunakan.
strength
(a) To increase the
kekuatan
Meningkatkan
and dan
(b) To increase the resistance to Mencegah
kakisan
(c) To improve the Membaiki
lapisan
hardness of pure metals.
kekerasan
corrosion
logam tulen.
of a pure metals.
logam tulen.
appearance
rupa
menghalang
of a pure metal.
logam tulen.
Experiment to compare the hardness of brass and pure copper.
5
Eksperimen untuk membandingkan kekerasan loyang dengan kuprum tulen.
(a) Hypothesis: / Hipotesis: Brass is harder than copper (b) Manipulated variable: / Pemboleh ubah dimanipulasi: Copper and brass block (c) Responding variable: / Pemboleh ubah bergerak balas: Hardness of the copper and brass block (d) Fixed variable: / Pemboleh ubah dimalarkan:
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Chemistry Form 4 • MODULE
(e) Apparatus: / Alat radas: Retort stand and clamp, 1 kg weight, string, metre ruler.
Materials: / Bahan-bahan: Steel ball, copper block, brass block
(f) Procedure: / Prosedur: 1. A steel ball bearing is tapped onto a copper block. Set-up of the apparatus: / Susunan alat radas:
Satu bola keluli dilekatkan di atas sebuah bongkah kuprum.
2. A 1 kg weight is hung at a height of 50 cm above the copper block as shown in the diagram. Sebiji pemberat 1 kg digantung setinggi 50 cm di atas bongkah kuprum seperti yang ditunjukkan.
Retort stand
3. Drop the 1 kg weight on the steel ball. Pemberat 1 kg dijatuhkan ke atas bebola keluli.
String
4. Measure the diameter of the dent formed on the copper block with a ruler.
1 kg weight
Diameter lekuk yang terbentuk di atas bongkah kuprum diukur dengan pembaris.
5. Repeat the experiment three times on the other part of the copper block.
Steel ball
Eksperimen diulang tiga kali, pada ruang berbeza pada bongkah kuprum yang sama.
Cellophane tape
6. Steps 1 to 5 are repeated using a brass block to replace the copper block.
Copper block
Langkah 1 hingga 5 diulang dengan menggunakan bongkah loyang, menggantikan bongkah kuprum.
(g) Results: / Keputusan: Experiment
Average diameter/cm
Eksperimen
1
2
3
Diameter of dent on copper block/cm
a
b
c
a + b + c = x 3
Diameter of dent on brass block/cm
d
e
f
d + e + f = y 3
Diameter purata / cm
(h) Discussion: / Perbincangan: The average diameter of dent on copper, x is larger than the average diameter of dent on brass, y. (i) Conclusion: / Kesimpulan:
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Brass is harder than copper// alloy is harder than pure metal.
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MODULE • Chemistry Form 4
Flow chart shows the composition, properties and uses of some alloys. Carta aliran di bawah menunjukkan komposisi, sifat-sifat dan kegunaan aloi-aloi. ALLOY / ALOI Major component / Komponen utama
COPPER / KUPRUM
IRON / FERUM Type of alloy/Jenis aloi
Type of alloy/Jenis aloi
BRONZE/GANGSA (90% Cu, 10% Sn) – Hard and strong,
does not corrode, (shiny surface)
–
BRASS/LOYANG (70% Cu, 30% Zn) – Hard and strong.
STEEL/KELULI (99% Fe, 1% C) – Hard and strong.
Keras dan kuat. Uses: / Kegunaan:
–
Keras dan kuat. Tidak berkarat (permukaan bersinar) Uses: / Kegunaan:
–
Musical instrument and Kitchenware
KELULI TAHAN KARAT
(74% Fe, 8% C, 18% Cr) – Shiny, strong and does
Keras dan kuat. Uses: / Kegunaan:
not rust
Construction of building and bridge and railway tracks
Alat muzik dan perkakas dapur
Building statue or monuments, medal, swords and artistic materials
STAINLESS STEEL
–
Bersinar, kuat dan tidak berkarat. Uses: / Kegunaan:
Making cutlery and surgical instrument
Pembinaan bangunan dan jambatan serta landasan keretapi.
Membuat sudu, garpu dan alat-alat pembedahan.
Pembuatan tugu atau monumen pingat, pedang dan bahan hiasan
ALUMINIUM / ALUMINIUM Type of alloy Jenis aloi
CUPRONICKEL KUPRONIKEL
(75% Cu, 25% Ni) – Shiny, hard and does
–
TIN / TIMAH Type of alloy Jenis aloi
DURALUMIN DURALUMIN
not corrode
(93% Al, 3% Cu & 1% Mn) – Light and strong
Making coins
– Uses: / Kegunaan: Building body of aeroplane and bullet train.
Bersinar, keras dan tidak berkarat. Uses: / Kegunaan: Membuat duit syiling
Ringan dan kuat.
Membuat rangka kapal terbang dan keretapi laju.
PEWTER / PEWTER (96% Sn, 3% Cu, 1% Sb) – Luster, shiny and strong
–
Berkilau, bersinar dan kuat. Uses: / Kegunaan:
Making souvenirs. Membuat cenderamata.
SYNTHETIC POLYMERS / POLIMER SINTETIK Polymer is a long chain molecules made up of a monomer.
1
large
number of small repeating
Polimer ialah molekul berantai panjang yang terbentuk daripada gabungan monomer. 2
Monomer is small identical
repeating
Monomer adalah unit kecil yang
berulang
banyak
unit kecil yang
identical sama
unit of dipanggil
units in the polymer. dalam polimer.
Polymers can be naturally occurring or synthetic.
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Polimer boleh didapati secara semula jadi atau sintetik.
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Chemistry Form 4 • MODULE
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Example of naturally occurring polymers and their monomers are: Contoh polimer semula jadi dan monomernya:
5
Synthetic Polymer / Polimer
Monomer / Monomer
Protein / Protein
Amino Acid / Asid amino
Starch / Kanji
Glucose / Glukosa
Rubber / Getah
Isoprene / Isoprena
Synthetic polymers are made polymers. The monomers are usually obtained from petroleum after refining and cracking process. Polimer sintetik adalah polimer buatan. Monomer biasanya adalah daripada petroleum yang telah mengalami penyulingan dan peretakan.
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Example of synthetic polymers, their monomers and uses: Contoh polimer sintetik, monomernya dan kegunaannya: Synthetic polymer
Monomer
Polimer sintetik
Example of uses
Monomer
Contoh kegunaan
Ethene, C2H4
Polythene Politena
Polypropene Polipropena
Plastic bags, shopping bags, plastic containers and plastic toys
Etena, C2H4
Beg plastik, beg membeli belah, bekas plastik dan permainan plastik
Propene, C3H6
Plastic bottles, plastic tables and chairs, car batteries casing and ropes Botol plastik, meja dan kerusi plastik, bekas bateri kereta dan tali
Propena, C3H6
Waterproof materials such as rain clothes, bags, shoes, artificial leather. Polyvinylchloride (PVC) Polivinil klorida (PVC)
Bahan kalis air seperti baju hujan, beg, kasut dan kulit tiruan.
Chloroethene, C2H3Cl
Insulation for electric wiring. Bahan penebat pendawaian wayar elektrik.
Kloroetena, C2H3Cl
Making water pipes because it does not rust. Paip air sebab ia tidak berkarat.
Styrene, C2H3C6H5
Polystyrene Polistirena
Packaging materials, disposable cups and plates
Stirena, C2H3C6H5
Bahan pembungkus, cawan dan pinggan pakai buang.
Perspex
Methylmetacrylate
Safety glass, car lamps and lens
Perspeks
Metil metakrilat
Kaca keselamatan, lampu kereta dan kanta
Hexane-1, 6-diol Terylene (polyester) Terilena (poliester)
Heksana-1, 6-diol
Clothing, sails, sleeping bags, ropes and fishing net
Benzene-1, 4-dicarboxylic acid
Pakaian, kain layar, tali dan jala
Benzena-1, 4-dikarboksilik asid
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joining
Polymerisation is the process of Pempolimeran ialah proses
penggabungan
together the large number of monomers to form a polymer. monomer-monomer untuk membentuk polimer.
Example: / Contoh: (a) Polymerisation of ethene: Pempolimeran etena:
n
H C H
H = C H
H – C – H n, n is large number up to a few thousands
Polythene
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H – C H
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MODULE • Chemistry Form 4
(b) Polymerisation of propene:
(c) Polymerisation of chloroethene:
Pempolimeran propena:
n
H C H
Pempolimeran kloroetena:
CH3 = C H
H – C H
Propene / Propena
CH3 – C – H n
Polypropene
n
H C H
H = C Cl
H – C H
Chloroethene / Kloroetena
Polyvinylchloride
Complete the following table related to issues of the use of polymers in everyday life.
8
H – C – Cl n
Lengkapkan jadual di bawah berkaitan isu penggunaan polimer sintetik dalam kehidupan seharian. Advantages of synthetic polymers
Environmental pollution from synthetic polymers Pencemaran alam sekitar dari penggunaan polimer sintetik
Kebaikan polimer sintetik
(a) Very stable and do not corrode . Sangat stabil dan tidak berkarat .
(b) Inert to chemical reaction.
(a) Disposal of synthetic polymers such as plastic bottles and containers cause blockage of drainage systems and river thus causing flash floods . Pembuangan polimer sintetik seperti botol plastik dan bekas tersekat yang menyebabkan sistem saliran dan sungai banjir kilat mengakibatkan .
Reducing pollution of synthetic polymers
Pengurangan pencemaran dari polimer sintetik
recycle and (a) Reduce, reuse the synthetic polymers. Mengurangkan, mengitar semula dan mengguna semula polimer sintetik.
biodegradable Lengai terhadap tindak balas (b) Open burning of polymers will release acidic and poisonous (b) Using polimer. kimia gas that will cause air pollution: . Menggunakan polimer Pembakaran polimer sintetik secara terbuka membebaskan gas strong . (c) Light and berasid dan beracun yang menyebabkan pencemaran udara: terbiodegradasi . kuat . Ringan dan – Burning most of the synthetic polymers will produce: Pembakaran kebanyakan polimer sintetik menghasilkan: (c) On-going research to produce (d) Cheap.
cheap biodegradable polymers. (i) carbon dioxide gas which cause green house effect . Penyelidikan berterusan kesan rumah hijau . karbon dioksida yang menyebabkan untuk menghasilkan polimer (ii) carbon monoxide which is poisonous . terbiodegradasi yang murah. beracun . karbon monoksida yang (d) Disintegrate plastics by – Burning of PVC will release hydrogen chloride gas which pyrolysis : Plastic can will cause acid rain . be disintegrated by heating at Pembakaran PVC membebaskan gas hidrogen klorida yang temperature between hujan asid . menyebabkan 400 – 800°C without oxygen. – Burning of synthetic polymers contains carbon and Penguraian plastik secara pirolisis : Plastik boleh diuraikan nitrogen such as nylon will produce highly poisonous dengan pemanasan pada suhu gas such as hydrogen cynide .
Murah.
shaped (e) Easily and coloured.
dibentuk Mudah dan diwarnakan.
Pembakaran polimer sintetik mengandungi karbon dan nitrogen seperti nilon membebaskan gas sangat beracun seperti hidrogen sianida .
antara 400 – 800 °C tanpa oksigen.
(c) Plastic containers that are left in open area collect rain water will become breeding ground for mosquito which will cause diseases such as dengue fever. Bekas plastik yang ditinggalkan di tempat terbuka menakung air nyamuk yang menyebabkan hujan menjadi tempat pembiakan penyebaran penyakit seperti demam denggi.
Glass / Kaca 1 Name the element which forms the major component of glass. Namakan unsur yang membentuk komponen utama kaca.
2 List the property of glass. Senaraikan sifat-sifat kaca.
Silicon dioxide
, SiO2 which exist naturally in
sand
Silikon dioksida
, SiO2 yang boleh didapati secara semula jadi di dalam
. pasir
.
Properties: / Sifat-sifat: Transparent, hard but brittle, non-porous, heat insulator, electric insulator, resistant to
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Chemistry Form 4 • MODULE
Complete the table below. Lengkapkan jadual di bawah. Types of glass Jenis kaca
Soda-lime glass Kaca soda kapur
Composition Komposisi Silicon dioxide, sodium carbonate or calcium calcium carbonate
Special properties Sifat istimewa
Borosilicate glass Kaca borosilikat
Silikon dioksida, boron dioksida, natrium oksida, aluminium oksida
durability kimia
Tahan kakisan bahan
High
–
tinggi
Pekali pengembangan haba haba Tidak tahan .
chemical
– Good
Low
mirrors, glass containers
.
kimia
.
Making cookware and laboratory
thermal expansion. rendah
Pekali pengembangan haba
heat
haba
.
glassware such as boiling tube and
when heated to
– Resistant to high temperature. Tahan tinggi.
Making flat glass, electrical bulbs,
durability
Tahan kakisan bahan
–
.
termal expansion but does not heat .
withstand
Silikon dioksida, natrium karbonat, kalsium karbonat
Silicion dioxide, boron dioxide, sodium oxide, aluminum oxide
chemical
– Good
Uses Kegunaan
beakers.
apabila dipanaskan pada suhu
– Optically transparent. Lut sinar.
chemical
– Good Fused glass Kaca silika terlakur
durability kimia
Tahan kakisan bahan
Silicon dioxide
– Low thermal expansion
Silikon dioksida
Pekali pengembangan haba
.
Laboratory glassware, lenses,
rendah
telescope mirrors, optical fibres.
.
high temperature – Can be heated to and resistance to thermal shock. tinggi Boleh dipanaskan pada suhu yang tahan terhadap pertukaran suhu yang cepat.
Lead glass Kaca plumbum
Silicon dioxide, sodium oxide, lead(II) oxide Silikon dioksida, natrium oksida, plumbum(II) oksida
– High
refractive index and
Indeks
biasan
Glittering
–
Kelihatan
dan
density
ketumpatan
appearance.
berkilat
,
.
yang tinggi
Tableware, crystal glass ware and decorative glassware.
.
Ceramics / Seramik 1
Name the elements found in ceramic. Namakan unsur-unsur yang terkandung dalam seramik.
Aluminium, silicon, oxygen and hydrogen 2
Ceramics are made from clay. Name the main component of clay. Seramik dibuat daripada tanah liat. Namakan komponen utama tanah liat.
which is rich in
hydrated aluminium silicate
Kaolin
yang mengandungi
aluminium silikat terhidrat
, Al2O32SiO2.2H2O. , Al2O32SiO2.2H2O.
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MODULE • Chemistry Form 4
Complete the following table for the properties and uses of ceramic.
3
Lengkapkan jadual berikut untuk menunjukkan sifat-sifat dan kegunaan seramik. Property/Sifat
Uses/Kegunaan
Hard and strong.
Building materials such as
Keras dan kuat.
Bahan binaan seperti
Chemically inert and non-corrosive.
cement
simen
tiles
, jubin
,
– Kitchenware such as cooking pots and plates. periuk
Perkakas dapur seperti
pinggan
dan
Tidak reaktif secara kimia dan tidak mudah menghakis.
– Decorative items such as vases and pottery.
Have high melting point and good insulator of heat, remain stable under high temperature.
Insulation such as parts.
lining
Penebat haba seperti enjin bahagian
melapik
Mempunyai takat lebur yang tinggi dan penebat haba yang baik serta stabil dalam suhu yang tinggi.
Penebat elektrik yang baik.
.
Barang hiasan seperti pasu dan lain-lain.
of furnace, wall of nuclear reactor and dinding
dinding relau,
engine
bagi reaktor nuklear dan
.
Electric insulator in electrical items such as electric cables .
Good insulator electric.
, bricks, roof and toilet bowl.
, batu-bata, atap dan tandas.
Penebat elektrik bagi alat-alat elektrik seperti kabel elektrik .
electric plugs
plug elektrik
,
oven
and
ketuhar
,
dan
Medical dental and apparatus such as orthopedic joint replacement, dental restoration and bone implants.
Non compressible.
perubatan Alat-alat palsu dan pemindahan tulang.
Tidak boleh dimampatkan.
pergigian
dan
seperti penukaran sendi ortopedik, gigi
Composite Materials / Bahan Komposit (a) Composite materials are structural materials that are formed by combining two or more different substances such as metal alloys ceramic glass polymer , , , and .
1
Bahan-bahan komposit adalah bahan yang diperbuat daripada gabungan dua atau lebih bahan berbeza seperti aloi seramik kaca polimer , , dan .
superior
(b) Composite materials have properties that are Bahan-bahan komposit mempunyai sifat-sifat yang
logam
,
than those of the original components.
lebih baik
berbanding dengan komponen-komponen asal.
Complete the table below:
2
Lengkapkan jadual di bawah: Types of composite materials
Components
Special properties
Komponen
Sifat istimewa
Example of uses Contoh kegunaan
Jenis bahan komposit
Superconductors Super konduktor
Reinforced concrete Konkrit yang diperkukuhkan
Copper(II) oxide, barium carbonate and Yttrium oxide heated to form a type of ceramic known as perovoskyte
Conduct electricity with no resistance when it is cooled at low temperature.
Kuprum(II) oksida, barium karbonat dan natrium oksida dipanaskan membentuk sejenis seramik dipanggil perovoskit
amat rendah.
Concrete ( cement , sand and pebbles) reinforced with steel and polymer fibers
m
Very
strong
moulded
and can be
into any shape.
devices(MRI), generators, transformers, computer parts and bullet train
Construction of building, bridges and oil platforms
kuat dan boleh Sangat dibentuk menjadi pelbagai bentuk.
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Konkrit ( simen , pasir dan batu kerikil) diperkukuhkan dengan keluli dan polimer gentian.
Boleh mengalirkan arus elektrik tanpa rintangan pada suhu yang
Used in medical magnetic-imaging
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Chemistry Form 4 • MODULE
High tensile strength, low density, easily moulded in
Plastic reinforced with glass fiber .
Fibre glass Plastik yang diperkukuhkan dengan kaca
Plastik yang diperkukuhkan dengan gentian kaca .
thin
Kaca fotokromik
boats, helmets
layers.
regangan tinggi, ketumpatan Daya rendah , mudah dibentuk menjadi nipis
lapisan
Photochromic glass
Making water storage tanks,
.
Darken
Photochromic substance like silver chloride embedded in glass/transparent polymers
when exposed to bright clear when light and becomes exposed to dim light.
Bahan fotokromik seperti argentum klorida digabungkan
gelap apabila dikenakan Menjadi cerah cahaya cerah dan menjadi dalam cahaya malap.
dengan kaca atau polimer lut sinar.
Making optical lens, car wind shield light intensity meters
EXERCISE / LATIHAN 1
The diagram below shows the reaction involve in the production of fertilizer Z in industry. Rajah berikut menunjukkan tindak balas yang terlibat dalam pembuatan baja Z dalam industri.
Ammonia
Process X Proses X
Ammonia
Process Y
Sulphuric acid
Compound Z Sebatian Z
Asid sulfurik
Proses Y
(a) (i)
Reaction P Tindak balas P
Name Process X and Process Y. Namakan Proses X dan Proses Y.
Haber process
Process X / Proses X:
(ii) Complete the following table related to process X and Y.
Process Y / Proses Y:
Contact process
Lengkapkan jadual berikut yang berkaitan dengan proses X dan Y. Process Proses
Catalyst Mangkin
Process X
Iron
Proses X
Besi
Process Y
Vandaium(V) oxide
Proses Y
Vanadium(V) oksida
Temperature/°C Suhu/°C
Pressure/ atm
Tekanan / atm
Balanced equation for the reaction that Involve a catalyst
Persamaan kimia tindak balas yang melibatkan mangkin
400 – 500
200
N2 + 3H2
2NH3
450 – 500
2 – 3
2SO2 + O2
2SO3
(b) Ammonia react with sulphuric acid through reaction P to produce compound Z. Ammonia bertindak balas dengan asid sulfurik melalui tindak balas P menghasilkan sebatian Z.
(i)
Write a balance equation for reaction P. Tuliskan persamaan seimbang bagi tindak balas P.
NH3 + H2SO4
(NH4 )2SO4
(ii) What is the type of reaction that takes place? Apakah jenis tindak balas yang berlaku?
Neutralisation
(iii) State one important use of compound Z. Nyatakan satu kegunaan penting sebatian Z.
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MODULE • Chemistry Form 4
(iv) Calculate the percentage by mass of nitrogen in compound Z. [Relative atomic mass: N = 14, S = 32, O = 16, H = 1] Hitungkan peratusan jisim nitrogen dalam sebatian Z. [Jisim atom relatif: N = 14, S = 32, O = 16, H = 1]
%N =
2 × 14 × 100% = 21.2% 2(14 + 4 × 1) + 32 + 4 × 16
The table shows the examples and component of four types of manufactured substances in industry.
2
Jadual berikut menunjukkan contoh-contoh dan komponen bagi empat jenis bahan buatan dalam industri. Type of manufactured substances
Example
Jenis bahan buatan
P
Component
Contoh
Komponen
Cement, sand, small pebbles and steel
Reinforced concrete Konkrit yang diperkukuhkan
Q
Bronze / Gangsa
Polymer / Polimer
R
Glass / Kaca
S
Simen, pasir, batu kecil dan keluli
Copper and tin / Kuprum dan stanum Chloroethene / Kloroetena Silicon dioxide, sodium carbonate, calcium carbonate Silikon dioksida, natrium karbonat, kalsium karbonat
(a) State the name of P, Q, R and S. Namakan P, Q, R dan S.
P: Composite materials
Q: Alloy
R: Polyvinyl chloride
S: Soda-lime glass
(b) (i)
State two uses of reinforced concrete. Nyatakan dua kegunaan konkrit yang diperkukuhkan.
To make framework of buildings and bridges.
(ii) What is the advantage of using reinforced concrete compared to concrete? Apakah kelebihan konkrit yang diperkukuhkan berbanding dengan konkrit?
Reinforced concrete can withstand higher pressure/support heavier loads/ stronger/ higher tensile strength than concrete. (c) (i)
Draw the arrangement of particles in Lukis susunan atom dalam
Pure copper / Kuprum tulen
Bronze / Gangsa Copper
Copper
Tin
(ii) Bronze is harder than pure copper. Explain. Gangsa lebih keras daripada kuprum. Terangkan. – Atoms of pure copper metal are the of same size, they arranged orderly in layers. – Layers of atoms are easily slide over each other when external force is applied on them. – The size of tin atoms which are bigger than copper in bronze disrupt the orderly arrangement of copper atoms.
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– Layers of metal atoms are prevented from sliding each other when external force is applied.
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Chemistry Form 4 • MODULE
(d) The diagram shows the structure of R. / Rajah berikut merupakan struktur bagi R.
(i)
H C H
H – C C1
n
Draw the structural formula for monomer R. / Lukiskan formula struktur bagi monomer R.
H H C = C H C1
(ii) State one use of polymer R.
Nyatakan satu kegunaan polimer R.
Pipe / wire cables / bags / footwear
(iii) State two ways how R causes environmental pollution.
Nyatakan dua cara R menyebabkan pencemaran alam.
– R is non biodegradable, it can cause blockage of drainage system and flash flood. – Burning of R produces hydrogen chloride gas which is poisonous and acidic. (e) (i)
Explain why glass containers are more suitable for storing acid in the laboratory. Terangkan mengapa bekas kaca lebih sesuai digunakan untuk menyimpan asid di dalam makmal.
Glass is chemically inert/ glass is non-reactive
(ii) Soda-lime glass cannot withstand high temperature. State the name of another type of glass that is more heat resistant.
Kaca soda kapur tidak tahan suhu yang tinggi. Namakan jenis kaca lain yang lebih tahan haba.
Borosilicate glass
Objective Questions / Soalan Objektif 1
Which of the following are the uses of sulphuric acid? Antara berikut, yang manakah adalah kegunaan asid sulfurik?
I Detergent II
Cat
Fertiliser
IV Synthetic fiber
Baja
A B 2
Gentian sintetik
C
I and II only I dan II sahaja
D
III and IV only III dan IV sahaja
I, II dan IV sahaja
I, II, III and IV I, II, III dan IV
SO2
II
SO3
III
H2S2O7
IV
Fe
2NH3
Which of the following is the function of iron, Fe in the process? Antara berikut, yang manakah adalah fungsi besi, Fe dalam proses itu?
Rajah di bawah menunjukkan peringkat I, II, III dan IV dalam Proses Sentuh.
I
N2 + 3H2
I, II and IV only
The diagram below shows the stages I, II, III and IV in the Contact Process.
S
The equation below shows chemical equation to produce ammonia in Haber Process. Persamaan tindak balas berikut menunjukkan persamaan kimia untuk menghasilkan ammonia dalam Proses Haber.
III Paint
Detergen
3
H2SO4
Which of the following stages requires the use of a catalyst?
A B C D
To lower the pressure required for the process. Merendahkan tekanan yang diperlukan untuk proses itu.
To lower the temperature required for the process. Merendahkan suhu yang diperlukan untuk proses itu.
To increase the rate of production of ammonia. Untuk meningkatkan kadar pengeluaran ammonia.
To increase the percentage of production of ammonia. Untuk meningkatkan peratus penghasilan ammonia.
Antara peringkat berikut, yang manakah memerlukan mangkin?
I II
C D
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MODULE • Chemistry Form 4
4
The diagram below shows the arrangement of atoms in alloy X.
8
Rajah di bawah menunjukkan susunan atom dalam aloi X.
Which of the following are the characteristics of synthetic polymers that causes environmental pollution? Antara berikut, yang manakah adalah ciri-ciri polimer sintetik yang menyebabkan pencemaran alam sekitar?
I
Copper/Kuprum
Polymers are non biodegradable Polimer adalah tidak terbiodegradasi
II
Zinc/Zink
Polymers dissolve in water and increase pH of water Polimer larut dalam air dan meningkatkan pH air
III Burning of polymers release toxic gas Pembakaran polimer membebaskan gas beracun
What is alloy X?
IV Disposal of polymers promote excessive growth of algae
Apakah aloi X?
A B 5
C
Brass Loyang
D
Bronze Gangsa
Pembuangan polimer meningkatkan pertumbuhan alga berlebihan
Cupronickel
A
Kupronikel
Duralumin
B
Duralumin
C
An alloy Y is used to make a body of an aeroplane. Which of the following is alloy Y and its major component?
D
Aloi Y digunakan untuk membuat badan kapal terbang. Antara berikut, yang manakah adalah aloi Y dan komponen utamanya?
Alloy Y
Major component
Duralumin
Magnesium
Duralumin
Magnesium
Duralumin
Aluminium
Duralumin
Aluminium
Bronze
Copper
Gangsa
Kuprum
C
Cupronickel
Copper
Kupronikel
Kuprum
D
Aloi Y
A B C D 6
Komponen utama
Which type of glass is suitable for making beakers and test tubes that can be used for heating? Kaca yang manakah adalah sesuai untuk membuat bikar dan tabung uji yang boleh digunakan untuk pemanasan?
A B 7
Lead glass Kaca plumbum
Soda-lime glass Kaca soda kapur
C D
9
A B
What is glass X?
Hard and strong Keras dan kuat
Good insulator electric Penebat elektrik yang baik
Remain stable under high temperature Kekal stabil pada suhu tinggi
Chemically inert and non corrosive Lengai terhadap bahan kimia dan tidak terkakis
Maklumat berikut adalah berkaitan dengan bahan Z yang digunakan dalam keretapi laju.
Conducts electricity with no resistance at low temperature.
Photochromic glass
Apabila kaca X dipanaskan dengan kuat dan seterusnya dimasukkan ke dalam air sejuk, kaca itu tidak pecah.
II, III and IV only II, III dan IV sahaja
10 The following information is about substance Z which is used in bullet train.
Mengkonduksi elektrik tanpa rintangan pada suhu rendah.
Kaca fotokromik
When the glass X is heated to a high temperature and plunged into cold water, the glass does not crack.
I, III and IV only I, III dan IV sahaja
Seramik digunakan untuk membuat dinding reaktor nuklear. Antara berikut, yang manakah adalah ciri seramik untuk penggunaan itu?
Borosilicate glass
Maklumat di bawah menunjukkan sifat kaca X.
II and III only II dan III sahaja
Ceramic is used to make wall of reactor nuclear. Which of the following is the characteristic of ceramic for the usage?
Kaca borosilikat
The information below shows the property of a glass X.
I and III only I dan III sahaja
What is substance Z? Apakah bahan Z?
A B C D
Fiber glass Duralumin
Superconductors Super konduktor
Polyvinylchloride Polivinil klorida
Fibre glass Plastik yang diperkukuhkan dengan kaca
Apakah kaca X?
A
m
Soda-lime glass Kaca soda kapur
C D
Fused glass Kaca silika terlakur
Borosilicate glass Kaca borosilikat
Publica
n Sdn.
182
tio
Nil a
B
Lead crystal glass Kaca plumbum
d. Bh
08-Chem F4 (3p).indd 182
12/9/2011 5:54:33 PM