AQA GCSE Combined Science: Trilogy — Chemistry Paper 2 (Foundation Tier)

Total marks: 70 · Duration: 75 minutes · Tier: Foundation

Instructions to candidates

Answer all questions in the spaces provided.
You are expected to use a calculator where appropriate.
This paper covers Topics 13–17: The Rate and Extent of Chemical Change, Organic Chemistry, Chemical Analysis, Chemistry of the Atmosphere, and Using Resources.
The maximum mark for this paper is 70. The marks for each question are shown in brackets.

Paper

Section A — Multiple Choice (5 marks)

For each question, choose the one correct answer.

1. Which of these will speed up a chemical reaction? (1 mark) A) Lowering the temperature B) Adding a catalyst C) Using larger lumps D) Using a lower concentration

2. Crude oil is a mixture that is separated by… (1 mark) A) filtration B) fractional distillation C) crystallisation D) chromatography

3. Which gas makes up about 78% of clean dry air? (1 mark) A) Oxygen B) Carbon dioxide C) Nitrogen D) Argon

4. Which substance is produced when a hydrocarbon burns completely? (1 mark) A) Carbon monoxide B) Carbon dioxide and water C) Hydrogen only D) Soot

5. Drinking water that is safe to drink is described as… (1 mark) A) pure B) distilled C) potable D) salty

Section B — Structured Questions (65 marks)

6. A student investigated the rate of reaction between marble chips and dilute hydrochloric acid. (a) Name the gas produced in this reaction. (1 mark) (b) Describe two ways the student could measure the rate of this reaction. (2 marks) (c) Explain why the reaction goes faster when the temperature is increased. (3 marks) (d) The student repeated the experiment using powdered marble instead of chips. Explain why the reaction is faster with powder. (2 marks)

7. A catalyst can change the rate of a reaction. (a) What is a catalyst? (2 marks) (b) Explain why catalysts are useful in industry. (2 marks)

8. Crude oil is an important raw material. (a) Crude oil is mostly made of compounds called hydrocarbons. What is a hydrocarbon? (2 marks) (b) The fractions from crude oil have different boiling points. Explain why short-chain hydrocarbons have lower boiling points than long-chain ones. (2 marks) (c) Name the process that breaks long hydrocarbon molecules into smaller, more useful ones. (1 mark) (d) Give one use of a fraction obtained from crude oil. (1 mark)

9. Chemical analysis is used to identify substances. (a) A gas relights a glowing splint. Name this gas. (1 mark) (b) Describe the test, and the result, for carbon dioxide gas. (2 marks) (c) A student used paper chromatography to separate the dyes in an ink. Explain why one dye travels further up the paper than another. (2 marks) (d) State one advantage of using an instrumental method of analysis rather than a chemical test. (1 mark)

10. The Earth's atmosphere has changed over time. (a) Name the gas, released by early volcanoes, that made up most of the early atmosphere. (1 mark) (b) Explain how the amount of oxygen in the atmosphere increased over millions of years. (2 marks) (c) Carbon dioxide and methane are greenhouse gases. Describe how greenhouse gases cause global warming. (3 marks) (d) Give one human activity that increases the amount of carbon dioxide in the atmosphere. (1 mark)

11. Burning fuels can release pollutants. (a) Name the gas, produced by incomplete combustion, that is poisonous because it reduces the blood's ability to carry oxygen. (1 mark) (b) Sulfur dioxide from burning fuels causes a type of pollution. Name it. (1 mark)

12. The Earth's resources are used to make useful products. (a) Explain the difference between a finite resource and a renewable resource. (2 marks) (b) Give two reasons why metals such as aluminium are recycled. (2 marks)

13. This question is about reducing the use of resources. A company wants to reduce the environmental impact of making and using a glass bottle. Explain how reusing and recycling glass bottles can reduce the use of resources and energy. In your answer, compare reusing with recycling. (6 marks)

14. This question is about organic chemistry, the atmosphere and resources. (a) What is a hydrocarbon? (2 marks) (b) Name the process used to separate crude oil into fractions. (1 mark) (c) Explain why short-chain hydrocarbons make better fuels than long-chain ones. (2 marks) (d) Write the word equation for the complete combustion of methane. (2 marks) (e) Name the gas that turns limewater cloudy, and state what this gas is. (2 marks) (f) Describe the test, and result, that shows a liquid contains water (using anhydrous copper sulfate). (2 marks) (g) Explain how carbon dioxide acts as a greenhouse gas. (3 marks) (h) Give two possible effects of climate change. (2 marks) (i) What is meant by potable water? (1 mark) (j) Describe how potable water is produced from fresh water. (3 marks) (k) Give two ways the use of resources can be reduced. (2 marks)

Mark Scheme

1. B 2. B 3. C 4. B 5. C [5 × 1 = 5]

6. (a) carbon dioxide B1 (b) any two: measure volume of gas with a gas syringe; measure loss of mass on a balance; time for a cross to disappear (n/a here) B1 B1 (c) particles have more energy / move faster (1); collide more frequently (1); more collisions have enough energy to react (1) B1 B1 B1 (d) powder has a larger surface area (1); so more frequent collisions / faster rate (1) B1 B1 [8]

7. (a) a substance that speeds up a reaction (1) without being used up (1) B1 B1 (b) any two ideas: lower temperatures/energy needed → saves energy/money; faster production B1 B1 [4]

8. (a) a compound (1) of hydrogen and carbon only (1) B1 B1 (b) short chains have weaker intermolecular forces (1) so less energy is needed to separate them (1) B1 B1 (c) cracking B1 (d) any one: petrol/diesel as fuel, bitumen for roads, etc. B1 [6]

9. (a) oxygen B1 (b) bubble through limewater (1); it turns cloudy/milky (1) B1 B1 (c) it is more soluble in the solvent / less strongly attracted to the paper (1) so it is carried further (1) B1 B1 (d) any one: faster, more accurate, works on tiny samples B1 [6]

10. (a) carbon dioxide B1 (b) algae and plants evolved (1); photosynthesis released oxygen (1) B1 B1 (c) gases absorb the heat (long-wave/infrared radiation) radiated from the Earth (1); re-radiate it back (1); so the atmosphere warms up (1) B1 B1 B1 (d) any one: burning fossil fuels, deforestation B1 [7]

11. (a) carbon monoxide B1 (b) acid rain B1 [2]

12. (a) finite resources are being used up faster than they form / will run out (1); renewable resources can be replaced/reformed (1) B1 B1 (b) any two: saves energy, saves finite ore/resources, less mining/landfill, cheaper B1 B1 [4]

13. Levels-marked, 6 marks. Indicative content: reuse — wash and refill the same bottle; very little energy; no need to remake the bottle. Recycle — crush and melt the glass to make new bottles; saves raw materials (sand) but still needs energy to melt. Both reduce the use of finite resources and landfill; reuse generally uses less energy than recycling.

Level 3 (5–6): both reuse and recycle explained and compared, linked to resources/energy.

Level 2 (3–4): both covered with some correct detail.

Level 1 (1–2): isolated relevant points.

0: nothing relevant. [6]

14. (a) a compound (1) containing only hydrogen and carbon (1) B1 B1 (b) fractional distillation B1 (c) short chains are more flammable / ignite more easily / less viscous (1+1) B1 B1 (d) methane + oxygen → carbon dioxide + water B1 B1 (e) carbon dioxide (1); identified by limewater turning cloudy/milky (1) B1 B1 (f) anhydrous copper sulfate (1); turns from white to blue (1) B1 B1 (g) absorbs heat/infrared radiated from the Earth (1); re-radiates it back (1); warming the atmosphere (1) B1 B1 B1 (h) any two: ice melting, sea-level rise, extreme weather, habitat loss B1 B1 (i) water that is safe to drink B1 (j) choose a fresh-water source (1); filter to remove solids (1); sterilise e.g. with chlorine (1) B1 B1 B1 (k) any two: reduce, reuse, recycle B1 B1 [22]

AQA GCSE Combined Science (Trilogy) — Chemistry Paper 2 (Foundation Tier)