# Describe what is meant by diffusion and explain why diffusion occurs more quickly in gases than in liquids.

> Cambridge International IGCSE Chemistry (0620) — 1.2 Diffusion · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration
2. Diffusion involves random movement of particles
3. In gases, particles are further apart / have greater spaces between them than in liquids
4. Gas particles move faster / have higher kinetic energy than liquid particles (at the same temperature), so collisions are less frequent, allowing particles to travel further before being impeded

## Key terms

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

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/describe-what-is-meant-by-diffusion-87c4b3e2) · Published by Druglandscape Ltd.