# Explain how increasing the concentration of a reactant in solution increases the rate of a chemical reaction, using collision theory.

> IB DP Chemistry Standard Level (2023 syllabus) — R2.2 How fast? The rate of chemical change · Explain · 4 marks

## Mark scheme (4 marks)

1. Increasing concentration means more particles (molecules/ions) per unit volume
2. This leads to a greater frequency of collisions between reactant particles
3. A greater proportion / larger number of collisions exceed the activation energy
4. Therefore the rate of reaction increases

## Key terms

- [concentration](https://www.gradenine.co.uk/glossary/concentration)
- [collision theory](https://www.gradenine.co.uk/glossary/collision-theory)

## Related

- [Revision notes for IB DP Chemistry Standard Level (2023 syllabus)](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/explain-how-increasing-the-concentration-of-8b975e4f) · Published by Druglandscape Ltd.