# Describe what happens to the particles in a substance when it changes from a liquid to a gas, and explain why substances with stronger forces between their particles have higher boiling points.

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

## Mark scheme (4 marks)

1. Particles in a liquid gain energy (when heated to the boiling point)
2. The forces between the particles are overcome / broken, allowing particles to separate and move freely / independently
3. Stronger forces between particles require more energy to overcome
4. Therefore a higher temperature (boiling point) is needed to supply enough energy to overcome these stronger forces

## Key terms

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

## Related

- [Revision notes for WJEC GCSE Chemistry (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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/describe-what-happens-to-the-particles-8fd95e4c) · Published by Druglandscape Ltd.