# Explain why decreasing the surface area of a solid reactant decreases the rate of reaction.

> Edexcel GCSE Chemistry (1CH0) — 7.1 Rates of reaction · Explain · 4 marks

> A student is investigating how the size of zinc pieces affects the rate of reaction between zinc and sulfuric acid. The student notices that large pieces of zinc react much more slowly than small pieces of zinc of the same total mass.

## Mark scheme (4 marks)

1. Decreasing surface area means fewer exposed reacting particles (on the surface of the zinc)
2. This means collisions between zinc and acid particles are less frequent
3. There are fewer successful collisions per unit time
4. Therefore the rate of reaction decreases

## 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 Edexcel GCSE Chemistry (1CH0)](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-why-decreasing-the-surface-area-cd509e30) · Published by Druglandscape Ltd.