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

Chemistry – Practice exam 2

Sugarcane bioethanol, a methanol fuel cell, hydrogen iodide equilibrium, lithium-ion batteries, an amide pathway, an ester's spectra, lactase and iron tablets.

Marks by area of study

Unit 3 AOS 1: 34 marksUnit 3 AOS 2: 29 marksUnit 4 AOS 1: 19 marksUnit 4 AOS 2: 29 marksSustainability: 5 marksKey science skills: 5 marks

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

Q	Context	Marks
1	In Brazil, sugarcane is crushed and the sugars are fermented by yeast to produce bioethanol, which is used as	14
2	A direct methanol fuel cell (DMFC) is being developed to power portable electronic devices	11
3	Hydrogen and iodine vapour react in a sealed container to form hydrogen iodide	11
4	A mobile phone is powered by a lithium-ion battery	11
5	An industrial chemist plans to make compound E from ethene using the pathway below.	11
6	Compound Q is a colourless liquid with a fruity odour and molecular formula C4H8O2	10
7	Lactose, C12H22O11, is the main sugar in milk	10
8	An iron supplement is labelled ‘each tablet contains 65 mg of iron as iron(II) sulfate’	12

Section A: what each question tests (30 marks)

Q	Key knowledge	Area of study
1	comparison of biofuels and fossil fuels	Unit 3 AOS 1
2	converting ΔH between kJ mol⁻¹ and kJ g⁻¹	Unit 3 AOS 1
3	limiting reactant and energy released	Unit 3 AOS 1
4	efficiency of heating water with a fuel	Unit 3 AOS 1
5	comparison of respiration and combustion	Unit 3 AOS 1
6	balancing half-equations in acidic conditions	Unit 3 AOS 1
7	oxidation numbers	Unit 3 AOS 1
8	calculating standard cell potentials	Unit 3 AOS 1
9	limitations of predictions using the electrochemical series	Unit 3 AOS 1
10	efficiency of fuel cells compared with combustion	Unit 3 AOS 1
11	Faraday’s laws in fuel cells	Unit 3 AOS 2
12	the universal gas equation	Unit 3 AOS 1
13	energy profiles; activation energy with a catalyst	Unit 3 AOS 2
14	collision theory: surface area	Unit 3 AOS 2
15	units of equilibrium constants	Unit 3 AOS 2
16	effect of temperature on Kc and yield	Unit 3 AOS 2
17	electrolysis of molten salts	Unit 3 AOS 2
18	Faraday’s laws: time for electrodeposition	Unit 3 AOS 2
19	independent, dependent and controlled variables	Units 3–4 Key science skills
20	accuracy and precision	Units 3–4 Key science skills
21	naming esters	Unit 4 AOS 1
22	boiling points and intermolecular forces	Unit 4 AOS 1
23	addition reactions of alkenes	Unit 4 AOS 1
24	structural isomers	Unit 4 AOS 1
25	melting point as a test of purity	Unit 4 AOS 2
26	HPLC retention time	Unit 4 AOS 2
27	fragments in mass spectra	Unit 4 AOS 2
28	¹³C NMR: number of environments	Unit 4 AOS 2
29	fatty acids: saturation and melting point	Unit 4 AOS 2
30	chirality and medicines	Unit 4 AOS 1