# A sealed container holds a fixed amount of gas. The temperature of the gas is increased. Explain, using kinetic theory, why the pressure of the gas increases when its temperature is increased.

> WJEC A-Level Physics (Wales) — 3.3 Kinetic theory · Explain · 5 marks

## Mark scheme (5 marks)

1. Gas consists of particles that are in constant random motion
2. Increasing temperature increases the kinetic energy of the particles
3. Particles collide with the walls of the container more frequently
4. Each collision exerts a greater force on the walls (because particles hit harder / with greater momentum)
5. Greater force on the same area of wall means greater pressure

## 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 A-Level 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-container-holds-a-fixed-c0da14b2) · Published by Druglandscape Ltd.