# Explain, using particle theory, what happens to the particles in a gas when it is cooled until it becomes a solid.

> Edexcel GCSE Chemistry (1CH0) — 2.1 States of matter · Explain · 4 marks

## Mark scheme (4 marks)

1. As the gas cools, the particles lose energy / move more slowly
2. The gas condenses / particles come closer together to form a liquid
3. The liquid freezes / particles lose further energy so they can no longer move past each other
4. In the solid, the particles hold a regular arrangement and vibrate about fixed positions

## Key terms

- [particle theory](https://www.gradenine.co.uk/glossary/particle-theory)
- [gas](https://www.gradenine.co.uk/glossary/gas)
- [solid](https://www.gradenine.co.uk/glossary/solid)

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-using-particle-theory-what-happens-5078f190) · Published by Druglandscape Ltd.