Practice exam 7 · 30 pages · 120 marks · 15 minutes reading, 2 hours 30 minutes writing

Chemistry – Practice exam 7

Rocket propellants, a microbial fuel cell, the PCl5 equilibrium, the Downs cell, biodiesel from canola oil, identifying a carboxylic acid, starch and amylase, and hydrogen peroxide by titration.

Marks by area of study

Unit 3 AOS 1: 38 marksUnit 3 AOS 2: 27 marksUnit 4 AOS 1: 15 marksUnit 4 AOS 2: 31 marksSustainability: 5 marksKey science skills: 5 marks

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

Q	Context	Marks
1	Rocket engines carry both a fuel and an oxidant	12
2	In a microbial fuel cell, bacteria growing on the anode oxidise organic matter in wastewater, such as ethanoat	11
3	Phosphorus pentachloride decomposes when heated.	10
4	Sodium metal is manufactured by electrolysing molten sodium chloride in a Downs cell	12
5	Biodiesel is made from canola oil by reacting it with methanol in the presence of a sodium hydroxide catalyst	11
6	An unknown compound, W, has the molecular formula C5H10O2	11
7	Starch is a mixture of amylose (an unbranched polymer of α-glucose) and amylopectin (a branched polymer)	12
8	A hair bleach is labelled ‘6.0% w/v hydrogen peroxide’ (6.0 g of H2O2 per 100 mL)	11

Section A: what each question tests (30 marks)

Q	Key knowledge	Area of study
1	comparing fossil fuels	Unit 3 AOS 1
2	complete and incomplete combustion	Unit 3 AOS 1
3	volume–mass stoichiometry	Unit 3 AOS 1
4	q = mcΔT	Unit 3 AOS 1
5	redox in respiration	Unit 3 AOS 1
6	combining half-equations	Unit 3 AOS 1
7	energy transformations in redox reactions	Unit 3 AOS 1
8	calculating cell potentials	Unit 3 AOS 1
9	efficiency of fuel cells	Unit 3 AOS 1
10	measuring rates of reaction	Unit 3 AOS 2
11	dynamic equilibrium	Unit 3 AOS 2
12	pressure changes with equal numbers of gas particles	Unit 3 AOS 2
13	products of aqueous electrolysis	Unit 3 AOS 2
14	energy transformations in secondary cells	Unit 3 AOS 2
15	Faraday’s laws: cells in series	Unit 3 AOS 2
16	choosing measuring equipment	Unit 4 AOS 2
17	random and systematic errors	Units 3–4 Key science skills
18	naming ketones	Unit 4 AOS 1
19	chirality of amino acids	Unit 4 AOS 1
20	viscosity and intermolecular forces	Unit 4 AOS 1
21	addition of hydrogen halides to alkenes	Unit 4 AOS 1
22	substitution reactions of haloalkanes	Unit 4 AOS 1
23	atom economy and reaction type	Unit 4 AOS 1
24	test for unsaturation	Unit 4 AOS 2
25	preparing standard solutions	Unit 4 AOS 2
26	principles of HPLC	Unit 4 AOS 2
27	molecular ion peaks	Unit 4 AOS 2
28	IR identification of amines	Unit 4 AOS 2
29	the TMS reference in NMR	Unit 4 AOS 2
30	enzyme–substrate interactions	Unit 4 AOS 2