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

> Edexcel GCSE Chemistry (1CH0) — 5.3 Dynamic equilibria, calculations involving volumes of gases (Chem only) · Explain · 4 marks

> In the Haber process, nitrogen and hydrogen react to form ammonia. This is a reversible reaction that can reach dynamic equilibrium in a closed system.

## Mark scheme (4 marks)

1. A reversible reaction reaches dynamic equilibrium when the rate of the forward reaction equals the rate of the backward reaction.
2. Both the forward and backward reactions continue to occur (the reactions do not stop).
3. The concentrations of the reactants remain constant at dynamic equilibrium.
4. The concentrations of the products remain constant at dynamic equilibrium.

## 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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-what-is-meant-by-dynamic-a1a0c175) · Published by Druglandscape Ltd.