AQA GCSE Chemistry Paper 2 practice questions

What is on Paper 2?

• Paper 2 covers rates, equilibrium, organic chemistry, analysis, the atmosphere and using resources.
• It is a written paper of 1 hour 45 minutes, worth 100 marks — 50% of the GCSE.
• Questions are a mix of multiple choice, structured, closed short answer and extended response.
• Required practicals and maths or data skills from anywhere in the course can appear, so they are worth revising alongside the main topics.

Paper 2 practice questions with answers

12 original questions across the 6 Paper 2 topics. Try each one before reading the answer.

1. Rates of reaction and energy changes

   1. Which change always increases the rate of reaction?

   • • Cooling the mixture
   • • Using larger lumps
   • • Increasing concentration
   • • Adding water

   Answer: Increasing concentration

   More particles per volume means more frequent successful collisions.

2. Rates of reaction and energy changes

   2. Define activation energy.

   Answer: The minimum energy particles must have for a collision to result in a reaction.

   Say 'minimum energy' for the mark.

3. Reversible reactions and equilibrium

   3. What symbol shows a reaction is reversible?

   • • →
   • • ⇌
   • • =
   • • ≠

   Answer: ⇌

   A double-headed arrow shows the reaction can go both forward and backward.

4. Reversible reactions and equilibrium

   4. What is true about the rates of forward and backward reactions at equilibrium?

   Answer: They are equal

   At dynamic equilibrium, both reactions occur at the same rate.

5. Organic chemistry: hydrocarbons, alkenes, alcohols and polymers

   5. What elements make up a hydrocarbon?

   • • Carbon and oxygen
   • • Hydrogen and carbon
   • • Hydrogen and nitrogen
   • • Carbon and chlorine

   Answer: Hydrogen and carbon

   Hydrocarbons are compounds containing only hydrogen and carbon atoms.

6. Organic chemistry: hydrocarbons, alkenes, alcohols and polymers

   6. What is the general formula for alkanes?

   • • CnH2n
   • • CnH2n+2
   • • CnH2n-2
   • • CnHn

   Answer: CnH2n+2

   Alkanes follow the formula CnH2n+2 as they are saturated hydrocarbons.

7. Chemical analysis: purity, chromatography and tests

   7. What defines a pure substance in chemistry?

   • • A substance found in nature
   • • A single element or compound with no other substances mixed in
   • • Any liquid that looks clear
   • • A substance with a low boiling point

   Answer: A single element or compound with no other substances mixed in

   Chemical purity refers strictly to composition, not appearance or origin.

8. Chemical analysis: purity, chromatography and tests

   8. How does the melting behaviour of an impure substance differ from a pure one?

   Answer: It melts over a range of temperatures rather than at one sharp temperature

   Impurities disrupt the regular structure, causing melting over a range.

9. Chemistry of the atmosphere

   9. What was the early Earth's atmosphere thought to be mostly composed of?

   • • Oxygen
   • • Carbon dioxide
   • • Nitrogen
   • • Methane

   Answer: Carbon dioxide

   Volcanic activity released gases forming an early atmosphere thought to be mostly carbon dioxide, similar to Mars and Venus today.

10. Chemistry of the atmosphere

    10. Name the process that removed carbon dioxide and produced oxygen in the early atmosphere.

    Answer: Photosynthesis

    Algae and later plants used photosynthesis, absorbing CO2 and releasing O2 over billions of years.

11. Using resources: water, life-cycle assessment and sustainability

    11. What does 'potable' mean when describing water?

    • • Chemically pure
    • • Safe to drink
    • • Free from all dissolved solids
    • • Distilled

    Answer: Safe to drink

    Potable water is safe to drink but still contains low levels of dissolved minerals and salts.

12. Using resources: water, life-cycle assessment and sustainability

    12. Name two methods used to sterilise fresh water to make it potable.

    Answer: Chlorination and use of ozone or ultraviolet light.

    These methods kill microorganisms that could otherwise cause illness.

Where Paper 2 marks are usually lost

• Explaining rate changes with 'more collisions' without saying why — link concentration or temperature to collision frequency or energy.
• Forgetting that equilibrium predictions need both the direction of shift and the reason.
• Drawing organic structures with the wrong number of bonds on carbon.
• Naming a test without its positive result — both are needed for the mark.
• Describing a life-cycle assessment in general terms instead of comparing the specific materials asked about.

How to pick up the extended-answer marks

• Spend the first 30 seconds underlining the command word — 'describe', 'explain' and 'evaluate' are marked differently.
• Plan one point per mark, each carrying a scientific term and a consequence. Short linked sentences beat one long paragraph.
• For 'evaluate' questions, include a benefit, a drawback and a judgement sentence at the end.
• For required practical questions, name the control variable and how the result was measured — method detail is where the marks sit.

Timing that works under pressure

• Work at roughly one mark per minute so you keep spare time for checking at the end.
• Bank the short recall questions first, then return to the longer answers with your remaining time.
• If a question stalls for more than two minutes, write down what you know and move on — partial marks still count.
• Leave five minutes to check units, significant figures and whether any question part was skipped over a page break.

Revise each Paper 2 topic

• Rates of reaction and energy changes (82 questions)
• Reversible reactions and equilibrium (77 questions)
• Organic chemistry: hydrocarbons, alkenes, alcohols and polymers (82 questions)
• Chemical analysis: purity, chromatography and tests (81 questions)
• Chemistry of the atmosphere (81 questions)
• Using resources: water, life-cycle assessment and sustainability (81 questions)

AQA Chemistry Paper 2 FAQs

What topics are on AQA GCSE Chemistry Paper 2?

Paper 2 assesses rates of reaction, equilibrium, organic chemistry, chemical analysis, chemistry of the atmosphere and using resources. Required practicals and data skills linked to these topics can also be examined.

How long is AQA GCSE Chemistry Paper 2?

It is a 1 hour 45 minute written exam worth 100 marks, which is 50% of the GCSE. Working at about one mark per minute leaves time to check your answers.

How should I revise for Chemistry Paper 2?

Practise answering questions rather than rereading notes. Short daily sets of five questions per topic, marked straight away, expose weak areas faster than a long passive revision session.