# "Explain" questions — OCR GCSE Chemistry A: Gateway Science (J248)

> 68 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. [A food scientist is investigating whether a sample of red food colouring is pure or a mixture of dyes. She uses paper ch…](https://www.gradenine.co.uk/q/a-food-scientist-is-investigating-whether-0a28ccd7)
2. [A scientist carries out electrolysis of molten lead bromide using inert electrodes. Explain what happens at each electro…](https://www.gradenine.co.uk/q/a-scientist-carries-out-electrolysis-of-12d38ed2)
3. [Explain why phytomining is considered a more sustainable method of metal extraction than traditional mining, and describ…](https://www.gradenine.co.uk/q/explain-why-phytomining-is-considered-a-255707a0)
4. [Explain why graphite can conduct electricity but most other giant covalent structures, such as diamond, cannot.](https://www.gradenine.co.uk/q/explain-why-graphite-can-conduct-electricity-282d900a)
5. [A student tests three unknown solutions to identify the halide ions present. They add a few drops of silver nitrate solu…](https://www.gradenine.co.uk/q/a-student-tests-three-unknown-solutions-3e0e187e)
6. [Carboxylic acids are a homologous series of organic compounds. Explain the typical acidic properties of carboxylic acids…](https://www.gradenine.co.uk/q/carboxylic-acids-are-a-homologous-series-44a24ddd)
7. [A student burns a piece of wood in a fireplace. The room feels warmer after the wood has been burning for a few minutes.…](https://www.gradenine.co.uk/q/a-student-burns-a-piece-of-515ef917)
8. [The contact process is used industrially to manufacture sulfuric acid. Explain why the conditions used in the contact pr…](https://www.gradenine.co.uk/q/the-contact-process-is-used-industrially-532dc1fa)

## Related

- [OCR GCSE Chemistry A: Gateway Science (J248) revision notes](https://www.gradenine.co.uk/learn/ocr-gcse-chemistry-a-gateway-science-j248)
- [OCR GCSE Chemistry A: Gateway Science (J248) past papers](https://www.gradenine.co.uk/past-papers/ocr-gcse-chemistry-a-gateway-science-j248)
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