# "Explain" questions — AQA A-Level Chemistry (7405)

> 101 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. [Explain why cracking is an important industrial process. In your answer, refer to both the feedstock used and the produc…](https://www.gradenine.co.uk/q/explain-why-cracking-is-an-important-0226f2d6)
2. [Explain how increasing the concentration of sodium thiosulfate solution increases the rate of its reaction with hydrochl…](https://www.gradenine.co.uk/q/explain-how-increasing-the-concentration-of-024276db)
3. [Explain why ammonia solution is classified as a weak base and describe how this affects the pH of a 0.1 mol/dm³ ammonia …](https://www.gradenine.co.uk/q/explain-why-ammonia-solution-is-classified-02dc8724)
4. [A student dissolves ammonium nitrate in water. The temperature of the solution decreases. Explain why the temperature de…](https://www.gradenine.co.uk/q/a-student-dissolves-ammonium-nitrate-in-04033396)
5. [Bromine water decolourises when it reacts with propene. A student investigates how the initial concentration of bromine …](https://www.gradenine.co.uk/q/bromine-water-decolourises-when-it-reacts-05654567)
6. [Crude oil is described as a finite resource. Explain what is meant by the term 'finite resource' and describe the origin…](https://www.gradenine.co.uk/q/crude-oil-is-described-as-a-071bf8a0)
7. [Explain why increasing the concentration of hydrochloric acid increases the rate of reaction between hydrochloric acid a…](https://www.gradenine.co.uk/q/explain-why-increasing-the-concentration-of-09f65385)
8. [Ethanol vapour can be produced by the reaction of ethene with steam in a closed container. The equation for the reaction…](https://www.gradenine.co.uk/q/ethanol-vapour-can-be-produced-by-0b914513)

## Related

- [AQA A-Level Chemistry (7405) revision notes](https://www.gradenine.co.uk/learn/aqa-a-level-chemistry-7405)
- [AQA A-Level Chemistry (7405) past papers](https://www.gradenine.co.uk/past-papers/aqa-a-level-chemistry-7405)
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