# Explain why increasing the concentration of a dissolved reactant increases the rate of a chemical reaction.

> Cambridge International IGCSE Chemistry (0620) — 6.2 Rate of reaction · Explain · 4 marks

## Mark scheme (4 marks)

1. Higher concentration means more particles (of reactant) in the same volume
2. Particles collide more frequently / there are more collisions per unit time
3. More collisions result in successful / effective collisions
4. Therefore the rate of reaction increases

## Key terms

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

## Related

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