# "Explain" questions — Eduqas A-Level Chemistry

> 115 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. [The reaction between hydrogen and iodine reaches a dynamic equilibrium in a closed container.

H₂(g) + I₂(g) ⇌ 2HI(g)

W…](https://www.gradenine.co.uk/q/the-reaction-between-hydrogen-and-iodine-00cbad39)
2. [Ethene (C₂H₄) is a hydrocarbon. A student states: 'When ethene burns completely in oxygen, the total mass of the product…](https://www.gradenine.co.uk/q/ethene-c-h-is-a-hydrocarbon-a-0281afee)
3. [A student uses paper chromatography to separate the coloured pigments in a sample of black ink. After running the chroma…](https://www.gradenine.co.uk/q/a-student-uses-paper-chromatography-to-0293441e)
4. [Pent-2-ene can exist as cis and trans stereoisomers. Explain why pent-2-ene can form cis and trans isomers, and state on…](https://www.gradenine.co.uk/q/pent-2-ene-can-exist-as-cis-and-052d4f56)
5. [Elements in the periodic table are arranged in periods and groups. Explain what is meant by the terms 'period' and 'grou…](https://www.gradenine.co.uk/q/elements-in-the-periodic-table-are-089e4e57)
6. [Zinc reacts with sulfuric acid according to the equation: Zn + H₂SO₄ → ZnSO₄ + H₂. A student adds a small amount of zinc…](https://www.gradenine.co.uk/q/zinc-reacts-with-sulfuric-acid-according-0900233d)
7. [When copper carbonate is heated, it decomposes to form copper oxide and carbon dioxide gas. A student heats 6.2 g of cop…](https://www.gradenine.co.uk/q/when-copper-carbonate-is-heated-it-09da6a60)
8. [Aldehydes and ketones are two families of organic compounds that contain the carbonyl group. Explain how the structure o…](https://www.gradenine.co.uk/q/aldehydes-and-ketones-are-two-families-0b472d6f)

## Related

- [Eduqas A-Level Chemistry revision notes](https://www.gradenine.co.uk/learn/eduqas-a-level-chemistry)
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