# Water exists as a solid, liquid or gas depending on temperature. Using the particle model, explain what happens to the particles in liquid water as it is heated to its boiling point and then changes into a gas.

> Eduqas GCSE Chemistry — 2.5 The production of important chemicals · Explain · 4 marks

## Mark scheme (4 marks)

1. Particles in the liquid gain (kinetic) energy as they are heated
2. At the boiling point, the forces between the particles are overcome / broken
3. This is a physical change — the chemical composition of the water remains the same
4. In the gas state, particles are the most spread apart / move freely and have the most energy

## Key terms

- [particle model](https://www.gradenine.co.uk/glossary/particle-model)
- [boiling point](https://www.gradenine.co.uk/glossary/boiling-point)

## Related

- [Revision notes for Eduqas GCSE Chemistry](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/water-exists-as-a-solid-liquid-2f5e2477) · Published by Druglandscape Ltd.