Practice exam 6 · 30 pages · 120 marks · 15 minutes reading, 2 hours 30 minutes writing

Chemistry – Practice exam 6

Ammonia as a fuel, the zinc–air cell, the Deacon process, the chlor-alkali industry, lactic acid and ethyl lactate, identifying an aldehyde, aspirin from willow bark and vitamin C by titration.

Marks by area of study

Unit 3 AOS 1: 26 marksUnit 3 AOS 2: 27 marksUnit 4 AOS 1: 23 marksUnit 4 AOS 2: 30 marksSustainability: 8 marksKey science skills: 8 marks

Section B: short-answer and extended-response questions (90 marks)

Q	Context	Marks
1	Ammonia is being trialled as a carbon-free fuel for large ships	11
2	Zinc–air button cells are used in hearing aids	10
3	Hydrogen chloride is a by-product of the manufacture of some plastics	11
4	Chlorine and sodium hydroxide are produced by electrolysing concentrated sodium chloride solution (brine) in a	11
5	Lactic acid, CH3CH(OH)COOH, is produced by the bacterial fermentation of glucose from crops such as corn	11
6	Compound Z has the molecular formula C4H8O	11
7	Extracts of willow bark have been used to relieve pain for thousands of years	12
8	Vitamin C (ascorbic acid, C6H8O6, M = 176.0 g mol−1) can be determined by titration with iodine solution, usin	13

Section A: what each question tests (30 marks)

Q	Key knowledge	Area of study
1	renewable and non-renewable fuels	Unit 3 AOS 1
2	effect of the state of water on ΔH	Unit 3 AOS 1
3	mass–mass stoichiometry with density	Unit 3 AOS 1
4	systematic errors in calorimetry	Unit 3 AOS 1
5	energy content of food	Unit 3 AOS 1
6	oxidation numbers: disproportionation	Unit 3 AOS 1
7	comparing standard cell potentials	Unit 3 AOS 1
8	the role of the salt bridge	Unit 3 AOS 1
9	fuel cells with acidic electrolytes	Unit 3 AOS 1
10	collision theory	Unit 3 AOS 2
11	using Q to predict the direction of reaction	Unit 3 AOS 2
12	Le Châtelier: temperature and pressure	Unit 3 AOS 2
13	predicting products of aqueous electrolysis	Unit 3 AOS 2
14	recharging an unfamiliar secondary cell	Unit 3 AOS 2
15	Faraday’s laws: charge required	Unit 3 AOS 2
16	percentage uncertainty	Units 3–4 Key science skills
17	experimental controls	Units 3–4 Key science skills
18	naming amines	Unit 4 AOS 1
19	semi-structural formulas of esters	Unit 4 AOS 1
20	boiling points and intermolecular forces	Unit 4 AOS 1
21	controlling the products of oxidation	Unit 4 AOS 1
22	conditions for esterification	Unit 4 AOS 1
23	primary standards	Unit 4 AOS 2
24	titration with dilution	Unit 4 AOS 2
25	HPLC: retention time and peak area	Unit 4 AOS 2
26	fragmentation in mass spectra	Unit 4 AOS 2
27	using IR to distinguish compounds	Unit 4 AOS 2
28	¹³C NMR environments	Unit 4 AOS 2
29	levels of protein structure	Unit 4 AOS 2
30	enzymes as catalysts	Unit 4 AOS 2