Practice exam 10 · 30 pages · 120 marks · 15 minutes reading, 2 hours 30 minutes writing

Chemistry – Practice exam 10

A candle in a sealed jar, a direct ethanol fuel cell, the water–gas shift reaction, lithium production, ethane-1,2-diol, identifying an amine, omega-3 fatty acids and ethanol in wine.

Marks by area of study

Unit 3 AOS 1: 34 marksUnit 3 AOS 2: 27 marksUnit 4 AOS 1: 19 marksUnit 4 AOS 2: 31 marksSustainability: 7 marksKey science skills: 4 marks

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

Q	Context	Marks
1	A candle burns inside a sealed 2.00 L glass jar of air at 25 °C and 100 kPa	11
2	A direct ethanol fuel cell uses an aqueous solution of ethanol as the fuel and a proton-exchange membrane as t	11
3	In the water–gas shift reaction, carbon monoxide reacts with steam to produce more hydrogen.	11
4	Lithium metal is produced by electrolysing molten lithium chloride	11
5	Ethane-1,2-diol, HOCH2CH2OH, is used as antifreeze and to make polyester	12
6	An unknown liquid, T, has the molecular formula C3H9N	11
7	Linolenic acid is an omega-3 fatty acid found in flaxseed and canola oils	11
8	The ethanol content of a white wine labelled ‘12.0% alc/vol’ was determined by a back titration.	12

Section A: what each question tests (30 marks)

Q	Key knowledge	Area of study
1	sustainability of biofuels	Unit 3 AOS 1
2	thermochemical equations from energy per gram	Unit 3 AOS 1
3	molar volume of gases	Unit 3 AOS 1
4	bomb calorimetry	Unit 3 AOS 1
5	energy from respiration	Unit 3 AOS 1
6	oxidation numbers	Unit 3 AOS 1
7	overall equations for galvanic cells	Unit 3 AOS 1
8	comparing fuel cells with combustion	Unit 3 AOS 1
9	effect of catalysts on rate and yield	Unit 3 AOS 2
10	Maxwell–Boltzmann distributions	Unit 3 AOS 2
11	Le Châtelier: temperature and gas solubility	Unit 3 AOS 2
12	factors affecting K_c	Unit 3 AOS 2
13	electrolysis of water	Unit 3 AOS 2
14	overcharging of secondary cells	Unit 3 AOS 2
15	Faraday’s laws: mass deposited	Unit 3 AOS 2
16	ethics in investigations	Units 3–4 Key science skills
17	percentage error	Units 3–4 Key science skills
18	naming alcohols	Unit 4 AOS 1
19	chain isomers	Unit 4 AOS 1
20	hydrogen bonding in isomers	Unit 4 AOS 1
21	oxidation of primary alcohols	Unit 4 AOS 1
22	the circular economy	Units 3–4 Cross-study
23	distillation	Unit 4 AOS 2
24	choosing indicators	Unit 4 AOS 2
25	systematic errors in titrations	Unit 4 AOS 2
26	factors affecting retention time	Unit 4 AOS 2
27	¹³C NMR environments	Unit 4 AOS 2
28	the fingerprint region	Unit 4 AOS 2
29	classifying fatty acids	Unit 4 AOS 2
30	primary structure and protein shape	Unit 4 AOS 2