# When a liquid is heated to its boiling point, it changes into a gas. Explain, in terms of particles, what happens to the arrangement and movement of particles during this change of state.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 1.1 States of matter · Explain · 4 marks

## Mark scheme (4 marks)

1. In a liquid, particles are close together / touching / in contact with each other, whereas in a gas the particles are far apart / spread out / much greater distances between them
2. In a liquid, particles move randomly but are able to flow / move past each other; in a gas, particles move randomly in all directions with no fixed positions
3. The particles gain energy (from heating), so the intermolecular forces between particles are overcome / broken
4. The particles in the gas have more energy / move faster than in the liquid, so there are no significant forces of attraction between them

## Key terms

- [liquid](https://www.gradenine.co.uk/glossary/liquid)
- [gas](https://www.gradenine.co.uk/glossary/gas)
- [particles](https://www.gradenine.co.uk/glossary/particles)

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](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/when-a-liquid-is-heated-to-a7c5e776) · Published by Druglandscape Ltd.