# Explain what is meant by dynamic equilibrium in a reversible reaction, and describe what happens to the concentrations of reactants and products once dynamic equilibrium has been reached.

> Edexcel GCSE Chemistry (1CH0) — 4.2 Reversible reactions and equilibria · Explain · 4 marks

## Mark scheme (4 marks)

1. A reversible reaction is one in which the products can react together to reform the reactants.
2. At dynamic equilibrium, the rate of the forward reaction is equal to the rate of the backward reaction.
3. Both the forward and backward reactions are still occurring (the equilibrium is dynamic/active).
4. The concentrations of reactants and products remain constant once dynamic equilibrium is reached.

## Key terms

- [dynamic equilibrium](https://www.gradenine.co.uk/glossary/dynamic-equilibrium)
- [reversible reaction](https://www.gradenine.co.uk/glossary/reversible-reaction)
- [concentration](https://www.gradenine.co.uk/glossary/concentration)

## 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-what-is-meant-by-dynamic-b1d4ee56) · Published by Druglandscape Ltd.