# A reversible reaction reaches dynamic equilibrium in a closed container. Explain what is meant by the term 'dynamic equilibrium'.

> AQA A-Level Chemistry (7405) — 3.1.10 Equilibrium constant Kp (A-Level only) · Explain · 5 marks

> A chemist studies the reversible reaction between nitrogen and hydrogen to form ammonia. The reaction is carried out in a sealed vessel until equilibrium is reached.

## Mark scheme (5 marks)

1. The forward and reverse reactions are both still occurring / taking place
2. The rate of the forward reaction equals the rate of the reverse reaction
3. The concentrations / amounts of reactants and products remain constant
4. The system must be closed / no substances can enter or leave the container
5. The equilibrium is described as 'dynamic' because particles are continually reacting (not static)

## Key terms

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

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](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/a-reversible-reaction-reaches-dynamic-equilibrium-12420847) · Published by Druglandscape Ltd.