# "Explain" questions — Eduqas GCSE Chemistry

> 83 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. [Copper has two naturally occurring isotopes: copper-63 and copper-65. Explain why the relative atomic mass of copper is …](https://www.gradenine.co.uk/q/copper-has-two-naturally-occurring-isotopes-013f0743)
2. [Silicon has three naturally occurring isotopes: silicon-28, silicon-29, and silicon-30. The relative atomic mass of sili…](https://www.gradenine.co.uk/q/silicon-has-three-naturally-occurring-isotopes-022fad3e)
3. [A student has an unknown solution that may contain one or more of the following ions: carbonate ions, sulfate ions, or h…](https://www.gradenine.co.uk/q/a-student-has-an-unknown-solution-0723f0e2)
4. [Magnesium has three naturally occurring isotopes: magnesium-24, magnesium-25, and magnesium-26. The relative atomic mass…](https://www.gradenine.co.uk/q/magnesium-has-three-naturally-occurring-isotopes-0e6598f4)
5. [A student adds a small piece of marble (calcium carbonate) to excess hydrochloric acid. The reaction produces carbon dio…](https://www.gradenine.co.uk/q/a-student-adds-a-small-piece-10a884f6)
6. [Ethene (C₂H₄) is a hydrocarbon produced during the cracking of long-chain alkanes. Ethene can react with bromine water. …](https://www.gradenine.co.uk/q/ethene-c-h-is-a-hydrocarbon-produced-1151431b)
7. [Boron has two naturally occurring isotopes, boron-10 and boron-11. The relative atomic mass of boron is 10.8. Explain wh…](https://www.gradenine.co.uk/q/boron-has-two-naturally-occurring-isotopes-19d02f17)
8. [A chemist is given two samples of a liquid. Sample A is described as pure ethanol. Sample B is described as a mixture of…](https://www.gradenine.co.uk/q/a-chemist-is-given-two-samples-1be6edb3)

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