# A student sets up a closed container in which the following reversible reaction reaches dynamic equilibrium: N₂(g) + 3H₂(g) ⇌ 2NH₃(g). The forward reaction is exothermic. Explain what is meant by dynamic equilibrium and predict the effect on the equilibrium position of increasing the temperature.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 3.3 Reversible reactions and equilibria · Explain · 4 marks

## Mark scheme (4 marks)

1. At dynamic equilibrium, the rate of the forward reaction is equal to the rate of the backward reaction.
2. The concentrations of reactants and products remain constant (not that reactions have stopped).
3. Increasing temperature shifts the equilibrium position in the direction of the endothermic reaction.
4. The equilibrium position shifts to the left / towards the reactants, so the yield of NH₃ decreases.

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](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-student-sets-up-a-closed-78b873b1) · Published by Druglandscape Ltd.