# "Explain" questions — WJEC A-Level Chemistry (Wales)

> 113 questions · chemistry

## How to answer

WHAT + WHY. Every point paired with a because. Structure: X happens because Y. This causes Z because … Assessment Objective: AO2. Every "explain" answer on this spec is marked against exactly this pattern.

## Sample questions

1. [Sodium and potassium are both elements in Group 1 of the periodic table. When a small piece of potassium is placed on co…](https://www.gradenine.co.uk/q/sodium-and-potassium-are-both-elements-00031907)
2. [A pharmacist is checking whether a batch of a pain-relief tablet is a pure compound or a mixture. She dissolves a small …](https://www.gradenine.co.uk/q/a-pharmacist-is-checking-whether-a-00637120)
3. [Cyclohexene and benzene are both cyclic hydrocarbons with the molecular formula suggesting multiple carbon–carbon bonds.…](https://www.gradenine.co.uk/q/cyclohexene-and-benzene-are-both-cyclic-02ffe6f0)
4. [A student carries out oxidation reactions on two unknown organic compounds, X and Y. Compound X is oxidised by acidified…](https://www.gradenine.co.uk/q/a-student-carries-out-oxidation-reactions-03d781aa)
5. [Ethanoic acid is a carboxylic acid. Explain what happens when ethanoic acid is added to sodium carbonate solution, and d…](https://www.gradenine.co.uk/q/ethanoic-acid-is-a-carboxylic-acid-06d50612)
6. [A technician is investigating three paint samples — paint P, paint Q and paint R. He carries out paper chromatography on…](https://www.gradenine.co.uk/q/a-technician-is-investigating-three-paint-0a1033fa)
7. [Chlorine has two naturally occurring isotopes: chlorine-35 and chlorine-37. Explain what is meant by the term isotope an…](https://www.gradenine.co.uk/q/chlorine-has-two-naturally-occurring-isotopes-0a884a5d)
8. [Propane (C₃H₈) is a hydrocarbon used as a fuel in camping stoves. When propane burns completely in oxygen, the products …](https://www.gradenine.co.uk/q/propane-c-h-is-a-hydrocarbon-used-0b925923)

## Related

- [WJEC A-Level Chemistry (Wales) revision notes](https://www.gradenine.co.uk/learn/wjec-a-level-chemistry-wales)
- [WJEC A-Level Chemistry (Wales) past papers](https://www.gradenine.co.uk/past-papers/wjec-a-level-chemistry-wales)
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