Practice exam 9 · 28 pages · 120 marks · 15 minutes reading, 2 hours 30 minutes writing

Chemistry – Practice exam 9

Methanol from captured CO2, designing a cell to light an LED, the NOCl equilibrium, a zinc–bromine flow battery, propyl propanoate, isomers of C4H10O, glutamic acid and MSG, and a calcium chloride hand warmer.

Marks by area of study

Unit 3 AOS 1: 39 marksUnit 3 AOS 2: 25 marksUnit 4 AOS 1: 18 marksUnit 4 AOS 2: 28 marksSustainability: 5 marksKey science skills: 6 marks

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

Q	Context	Marks
1	‘E-methanol’ is made by reacting carbon dioxide captured from the exhaust of a cement factory with hydrogen pr	12
2	Students were asked to build a single galvanic cell that would light a small LED, which needs a potential diff	11
3	Nitrosyl chloride, NOCl, is an orange-yellow gas that decomposes when heated.	11
4	Zinc–bromine flow batteries are used to store energy from solar farms	11
5	Propyl propanoate, which smells of pears, can be synthesised using propan-1-ol as the only organic starting ma	11
6	There are four alcohols with the molecular formula C4H10O: butan-1-ol, butan-2-ol, 2-methylpropan-1-ol and 2-m	11
7	Glutamic acid is a 2-amino acid found in many proteins	11
8	Students investigated whether anhydrous calcium chloride is suitable for a self-heating hand warmer	12

Section A: what each question tests (30 marks)

Q	Key knowledge	Area of study
1	refining crude oil	Unit 3 AOS 1
2	energy released per mole of CO₂	Unit 3 AOS 1
3	mass–mass stoichiometry	Unit 3 AOS 1
4	energy and temperature change	Unit 3 AOS 1
5	identifying redox reactions	Unit 3 AOS 1
6	oxidation half-equations in acidic solution	Unit 3 AOS 1
7	predicting reactions from E° values	Unit 3 AOS 1
8	fuel cell half-equations for an unfamiliar electrolyte	Unit 3 AOS 1
9	rate and amount of product	Unit 3 AOS 2
10	using K_c to find a concentration	Unit 3 AOS 2
11	removing a product	Unit 3 AOS 2
12	electroplating	Unit 3 AOS 2
13	mass changes in a rechargeable cell	Unit 3 AOS 2
14	Faraday’s laws in industry	Unit 3 AOS 2
15	presenting data	Units 3–4 Key science skills
16	precision	Units 3–4 Key science skills
17	naming compounds with two functional groups	Unit 4 AOS 1
18	semi-structural formulas	Unit 4 AOS 1
19	solubility and functional groups	Unit 4 AOS 1
20	formation of amides	Unit 4 AOS 1
21	hydrolysis of amides	Unit 4 AOS 1
22	percentage yield with a limiting reactant	Unit 4 AOS 1
23	green chemistry principles	Units 3–4 Cross-study
24	titration technique	Unit 4 AOS 2
25	concentration units	Unit 4 AOS 2
26	improving separation in HPLC	Unit 4 AOS 2
27	fragmentation in mass spectra	Unit 4 AOS 2
28	using IR to detect impurities	Unit 4 AOS 2
29	¹H NMR chemical shifts	Unit 4 AOS 2
30	carbohydrate polymers	Unit 4 AOS 2