Chapter 3 Chemical Formulae and Equations Paper 1 Answer all the questions. 1
The number of molecules in one mole of a gas is x. What is the number molecules in 8 g of oxygen gas? [Relative atomic mass: O, 16] A 8 x B 0.25 x C x D 0.5 x
2
How many water molecules are contained in 4.5 g of water? [Relative atomic mass: H, I; O,16] A 6 x 1023 B 4 x 1023 C 0.25 x 6 x 1023 D 1.5 x 6 x 1023
3
One mole of methane,CH4 and one of carbon dioxide,CO 2 have equal [Relative atomic mass: H, I; C,12; O,16] I volume at the same temperature and pressure II number of atoms III relative molecular mass IV number of molecules A IV only B I and IV only C II and IV only D I, II and IV only
4
What is the mass of one mole mole of chlorine molecules? molecules? [Relative atomic mass: CI, 35.5] A 35.5 g B 71.0 g C 6 x 1023 g D 24 g
5
How many moles of oxygen, O2, are needed for the complete combustion of one mole of propane, C3H8? A 3 B 5 C 8 D 10
6
What is the maximum mass of aluminium which can be obtained from 102 g of aluminium oxide, AI2O3? [Relative atomic mass: O,16; Al, 27] A 27 g B 51 g C 54 g D 108 g
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Chemistry SPM
7
The main ore of zinc is zinc blende, ZnS (Realative molecular mass: 97). When this ore is heated in air, the reaction is represented by the following equation. 2ZnS + 3O2
→
2ZnO + 2SO2
What is the volume of oxygen at room temperature and pressure would be needed to react completely with 97 g of ZnS? [Relative atomic mass: O,16; S, 32; Zn, 65] A 3 dm3 B 3 x 24 dm3 2 C 3 x 24 dm3 D 3 x 24 x 32 dm 3 8
The empirical formula of a liquid compound is known as C 2H4O. What other information is needed to work out its molecular formula? A The percentage composition of the compound B The relative molecular mass of the compound C The volume of the compound D The boiling point of the compound
9
How many moles of hydrogen atoms are there in 0.5 mole of glucose, C 6H12O6? A 6 B 3 C 1.5 D 0.5
gas, X 2, the compound formed 10 When hot iron gas fillings are heated in a stream of dry gas, X contains 34.5% by mass of iron. What is the empirical formula of the compound? [Relative atomic mass: X, 35.5; Fe, 56] A Fe X B Fe X 2 C Fe X 3 D Fe3 X 11 Methane reacts with steam according to the equation:
CH4(g) + H2O(g)
→
CO(g) + 3H2(g)
What is the volume of hydrogen obtained (at room temperature and pressure) when 16 g of methane is reacted with excess steam? [Relative atomic mass: C,12;O,16] A 24 dm3 B 48 dm3 C 60 dm3 D 72 dm3 12 Which of the following compounds has the similar empirical formula as ethene, C 2H4? A C6H12 B C6H6 C CH4 D C5H12
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Chemistry SPM
13 Potassium reacts with oxygen gas to form potassium oxide. Which of the following is a balanced chemical equation for the reaction? KO(s) A K(s) + O(g) K2O(s) B 2K(s) + O(g) KO2(s) C K(s) + O2(g) 2K2O(s) D 4K(s) + O2(g) →
→
→
→
14 Which of the following ions corresponds to the charges it carries? A B C D
Ion
Charges
P S NO3 Li
–3 +2 +1 –1
15 How many atoms are there in 1 mole of chlorine and 1 mole of argon? A B C D
1 mole of chlorine
1 mole of argon
6 x 1023 atoms 2 x 6 x 1023 atoms 2 x 6 x 1023 atoms 6 x 1023 atoms
6 x 1023 atoms 2 x 6 x 1023 atoms 6 x 1023 atoms 2 x 6 x 1023 atoms
16 Which of the following ions are cations? I Sulphate ions II Calcium ions III Ammonium ions IV Phosphate ions A I and II only B II and III only C III and IV only D I, II and III only 17 The following are the characteristics of an ion of element Q. • Consists of two negative negative charges• charges• • Consists of chromium and and oxygen atoms • Ratio of chromium chromium to oxygen oxygen atoms is 2:7 From the information above, it can be deduced that the ionic formula of the ion Q is A CrO2B Cr 2O72C CrO42D Cr 2O3 18 How many moles of ions are there in 1 mole of iron(III) oxide, Fe2O3? A 2 B 3 C 5 D 6
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Chemistry SPM
19 Ammonium phosphate is commonly used as a chemical fertiliser. What is the chemical formula of ammonia phosphate? A NH3PO4 B (NH4)2PO4 C NH4(PO4)3 D (NH4)3PO4
of X . 20 The figure below shows dry hydrogen gas is passed over a powdered oxide of X dry hydrogen
powdered X oxide
heat liquid
N
cold water
A liquid N N is is collected. The liquid N N would would A neutralise sodium hydroxide B turn white anhydrous copper(II) sulphate blue C has pH value greater than 7 D be a blue liquid
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Chemistry SPM
