Dexter C. Canalita
THE
STUDY OF MATTER – its composition, structure, properties, transformation from one form to another and the energy that accompanies this transformation.
Chemistry is the central science dealing with the composition of matter and the changes in composition that matter undergoes. Chemistry is also concerned with energy and energy changes of matter.
Copyright 2012 John Wiley & Sons, Inc
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The
ANSWER is that chemistry, by its very nature, is the CENTRAL SCIENCE, central to a fundamental understanding of other sciences and technologies.
“The Central Science” Astronomy Nuclear ChemistryHealth and Medicine Biology Physics
Biology Geology
Plant Sciences
Biochemistry Environmental Science
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ORGANIC CHEMISTRY – study of most carbon-based compounds. INORGANIC CHEMISTRY – deals with all substances which are not considered organic PHYSICAL CHEMISTRY - deals with the application of physical laws of chemical change and chemical systems. BIOCHEMISTRY – concerned with the chemistry of life processes and living organisms. ANALYTICAL CHEMISTRY – concerned mainly with the various techniques and laboratory methods to determine the composition of matter.
Collect the facts or data relevant to the problem.
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Done with carefully designed observations and experimentation.
Formulate a hypothesis that accounts for the data and that can be tested further. Plan and do additional experiments to test the hypothesis. Modify the hypothesis as necessary.
The Scientific Method Law: Statements of natural phenomena to which there are no known exceptions.
Hypothesis: A tentative explanation of the facts that can be tested further Theory: Well-tested hypothesis.
SOLIDS
LIQUIDS
GASES
Definite shape
Indefinite shape
Indefinite shape
Definite volume
Definite volume
Indefinite volume
Essentially incompressible
Only slightly compressible
Compressible
Particles are tightly packed together
Particles are mobile, able to move around each other
Particles are far apart and are small compared to the volume they occupy
Particles are held together by very strong forces of attraction
Particles are held together by strong forces of attraction
The attractive forces are so weak that the particles are independent of each other
Physical States of Matter
Classifications of Matter
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Chemistry is the study of matter and the changes it undergoes Matter is anything that occupies space and has mass.
A pure substance is a form of matter that has a definite composition and distinct properties.
Water
Sugar
Gold
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An element is a substance that cannot be separated into simpler substances by chemical means. • 114 elements have been identified • 82 elements occur naturally on Earth
gold, aluminum, lead, oxygen, carbon • 32 elements have been created by scientists technetium, americium, seaborgium
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A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions. Compounds can only be separated into their pure components (elements) by chemical means.
Water (H2O)
Glucose (C6H12O6)
Ammonia (NH3)
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A mixture is a combination of two or more substances in which the substances retain their distinct identities.
1. Homogenous mixture – composition of the mixture is the same throughout. soft drink, sea water
2. Heterogeneous mixture – composition is not uniform throughout. cement, fruit salad iron filings in sand 1.4
Physical means can be used to separate a mixture into its pure components.
distillation
magnet
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decantation - the process of pouring out the liquid leaving heavier solids to settle at bottom of container
filtration – separation of an insoluble solid from the liquid using a porous substance or filter paper
evaporation - separating a soluble solid from a liquid by transforming solvent to gaseous form
distillation – converting the liquid to gas, then collecting the liquid components by condensation
Physical or Chemical? A physical change does not alter the composition or identity of a substance. sugar dissolving ice melting in water A chemical change alters the composition or identity of the substance(s) involved.
hydrogen burns in air to form water 1.6
PROPERTIES OF MATTER • PHYSICAL PROPERTIES CLASSIFICATION EXTENSIVE PROPERTIES – properties that depends on the amount of material like mass, length and volume. INTENSIVE PROPERTIES – depend on the quality of material. Examples: odor, color, specific gravity, solubility, boiling point, melting point and electrical conductivity. • CHEMICAL PROPERTIES Describes a chemical change that a substances undergoes. Examples: burning,
Extensive and Intensive Properties An extensive property of a material depends upon how much matter is is being considered. • mass
• length • volume
An intensive property of a material does not depend upon how much matter is is being considered. • density • temperature • color
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SELF-CHECK • USING THE CLASSIFICATION SCHEME FOR MATTER, CLASSIFY THE FOLLOWING: ANSWERS: 1. VINEGAR 1. HOMOGENEOUS 2. HALO – HALO 2. HETEROGENEOUS 3. SALT WATER 3. HOMOGENEOUS 4. SAND IN WATER 4. HETEROGENEOUS 5. SUGAR 5. COMPOUND 6. ELEMENT 6. COPPER WIRE
SELF CHECK WHAT KIND OF CHANGE (PHYSICAL OR CHEMICAL) DOES EACH PROCESS BELOW UNDERGOES?
a) b) c) d) e) f) g) h)
Formation of clouds Corrosion of iron Tanning of leather Melting of sugar Burning of plastic Making of ice candy Ripening of papaya Cooking/boiling of eggs
ANSWER
a) b) c) d) e) f) g) h)
Physical Chemical Chemical Physical Chemical Physical Chemical Chemical
Matter - anything that occupies space and has mass. mass – measure of the quantity of matter
SI unit of mass is the kilogram (kg) 1 kg = 1000 g = 1 x 103 g weight – force that gravity exerts on an object weight = c x mass
A 1 kg bar will weigh
on earth, c = 1.0
1 kg on earth
on moon, c ~ 0.1
0.1 kg on moon 1.7
International System of Units (SI)
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Volume – SI derived unit for volume is cubic meter (m3)
1 cm3 = (1 x 10-2 m)3 = 1 x 10-6 m3 1 dm3 = (1 x 10-1 m)3 = 1 x 10-3 m3 1 L = 1000 mL = 1000 cm3 = 1 dm3
1 mL = 1 cm3
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Density – SI derived unit for density is kg/m3 1 g/cm3 = 1 g/mL = 1000 kg/m3 mass density = volume
m d= V
A piece of platinum metal with a density of 21.5 g/cm3 has a volume of 4.49 cm3. What is its mass? m d= V m = d x V = 21.5 g/cm3 x 4.49 cm3 = 96.5 g 1.7
K = 0C + 273.15 273 K = 0 0C 373 K = 100 0C
0F
= 9 x 0C + 32 5
32 0F = 0 0C 212 0F = 100 0C
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Convert 172.9 0F to degrees Celsius. 9 = x 0C + 32 5 0F – 32 = 9 x 0C 5 0F
5 x (0F – 32) = 0C 9 0C = 5 x (0F – 32) 9 0C = 5 x (172.9 – 32) = 78.3 9
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Dimensional Analysis Method of Solving Problems 1. Determine which unit conversion factor(s) are needed 2. Carry units through calculation 3. If all units cancel except for the desired unit(s), then the problem was solved correctly.
given quantity x conversion factor = desired quantity
given unit x
desired unit given unit
= desired unit
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Dimensional Analysis Method of Solving Problems
How many mL are in 1.63 L?
Conversion Unit 1 L = 1000 mL 1000 mL 1.63 L x = 1630 mL 1L 2 1L L 1.63 L x = 0.001630 1000 mL mL
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The speed of sound in air is about 343 m/s. What is this speed in miles per hour? conversion units meters to miles seconds to hours 1 mi = 1609 m
1 min = 60 s
1 mi 60 s m x x 343 s 1609 m 1 min
1 hour = 60 min
60 min mi x = 767 hour 1 hour
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