# A sealed metal container holds a fixed quantity of gas. When the container is placed in hot water, the pressure of the gas inside increases. Use kinetic theory to explain why the pressure of the gas increases when its temperature is raised.

> WJEC GCSE Physics (Wales) — 2.2 The kinetic theory and gas pressure · Explain · 4 marks

## Mark scheme (4 marks)

1. Increasing temperature increases the average kinetic energy (and speed) of the gas molecules
2. The gas molecules collide with the walls of the container more frequently
3. Each collision exerts a greater force on the walls because the molecules are moving faster
4. Greater force per unit area on the walls means pressure increases (and volume is constant so pressure must rise)

## Key terms

- [kinetic theory](https://www.gradenine.co.uk/glossary/kinetic-theory)
- [pressure](https://www.gradenine.co.uk/glossary/pressure)
- [temperature](https://www.gradenine.co.uk/glossary/temperature)

## Related

- [Revision notes for WJEC GCSE Physics (Wales)](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-sealed-metal-container-holds-a-5cc701d8) · Published by Druglandscape Ltd.