# Describe how increasing the surface area of a solid reactant affects the rate of reaction. Use ideas about particles in your answer.

> OCR GCSE Chemistry A: Gateway Science (J248) — C5.1 Monitoring chemical reactions · Describe · 4 marks

> A student is investigating how the size of marble chips affects the rate of reaction with hydrochloric acid. She uses large marble chips in one experiment and crushed marble powder in another, keeping all other conditions the same.

## Mark scheme (4 marks)

1. Increasing surface area means more (reacting) particles are exposed at the surface
2. Collisions between reactant particles happen more frequently / there are more frequent collisions
3. There are more successful collisions (per unit time)
4. Therefore the rate of reaction increases / the reaction is faster

## Key terms

- [surface area](https://www.gradenine.co.uk/glossary/surface-area)
- [rate of reaction](https://www.gradenine.co.uk/glossary/rate-of-reaction)

## Related

- [Revision notes for OCR GCSE Chemistry A: Gateway Science (J248)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-increasing-the-surface-area-5554be69) · Published by Druglandscape Ltd.