# When water boils, it undergoes a physical change rather than a chemical change. Explain the difference between a physical change and a chemical change, and use particle theory to explain what happens to the particles of water when it boils.

> WJEC GCSE Chemistry (Wales) — 2.5 The production of important chemicals · Explain · 4 marks

## Mark scheme (4 marks)

1. A physical change involves a change in state but the chemical composition remains the same / no new substance is formed
2. A chemical change requires a chemical reaction and produces substances with a different chemical composition to the reactants
3. When water boils, the forces between the particles are overcome / broken
4. The particles gain energy and move apart / spread out / move freely / become a gas

## Key terms

- [physical change](https://www.gradenine.co.uk/glossary/physical-change)
- [chemical change](https://www.gradenine.co.uk/glossary/chemical-change)

## Related

- [Revision notes for WJEC GCSE Chemistry (Wales)](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-water-boils-it-undergoes-a-030e473d) · Published by Druglandscape Ltd.