# "Explain" questions — Pearson Edexcel International GCSE Chemistry (4CH1)

> 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. [A student prepares a sample of copper(II) sulfate solution by adding dilute sulfuric acid to an excess of copper(II) car…](https://www.gradenine.co.uk/q/a-student-prepares-a-sample-of-0504bf78)
2. [When ammonium chloride dissolves in water, the temperature of the water decreases. Explain what this temperature change …](https://www.gradenine.co.uk/q/when-ammonium-chloride-dissolves-in-water-099af3fa)
3. [Explain why two atoms of the same element can have different mass numbers.](https://www.gradenine.co.uk/q/explain-why-two-atoms-of-the-0b0253bc)
4. [The reaction between hydrogen and iodine vapour is reversible. In a closed container, the following reaction reaches dyn…](https://www.gradenine.co.uk/q/the-reaction-between-hydrogen-and-iodine-0dfc1d68)
5. [Ethene and ethane are both hydrocarbons that can be produced from crude oil. Explain why ethene is described as an unsat…](https://www.gradenine.co.uk/q/ethene-and-ethane-are-both-hydrocarbons-0eb8a6d7)
6. [Magnesium oxide is an ionic compound with a giant lattice structure. Explain why magnesium oxide has a high melting poin…](https://www.gradenine.co.uk/q/magnesium-oxide-is-an-ionic-compound-0f589620)
7. [Explain why a substance in the gaseous state diffuses much more quickly than the same substance in the liquid state.](https://www.gradenine.co.uk/q/explain-why-a-substance-in-the-0f841413)
8. [Lead, carbon and gold are three substances found in the reactivity series. A student heats lead oxide with carbon in a c…](https://www.gradenine.co.uk/q/lead-carbon-and-gold-are-three-10164569)

## Related

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