# A sealed rigid container holds a fixed quantity of gas. The container is placed in a freezer, causing the temperature of the gas to decrease. Explain, in terms of particles, what happens to the pressure of the gas as its temperature decreases.

> Eduqas A-Level Physics — 2.3 Capacitance (A-Level only) · Explain · 5 marks

## Mark scheme (5 marks)

1. As temperature decreases, the average kinetic energy of the gas particles decreases
2. The particles move more slowly
3. The particles collide with the container walls less frequently
4. Each collision exerts a smaller force on the walls (particles hit with less force)
5. Therefore the pressure decreases (because pressure is force per unit area and both force and collision frequency are reduced)

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Physics](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-rigid-container-holds-a-a4e9b21e) · Published by Druglandscape Ltd.