# Explain what happens to the pressure of a fixed mass of gas when it is heated at constant volume, in terms of the behaviour of the gas particles.

> Eduqas A-Level Physics — 4.1 Thermal physics · Explain · 5 marks

> A sealed metal canister contains a fixed mass of gas. The canister is placed in an oven and its temperature rises.

## Mark scheme (5 marks)

1. Heating the gas increases the temperature / gives the particles more energy
2. The particles move faster / have greater average speed
3. Particles collide with the walls more frequently / more often
4. Each collision exerts a greater force on the walls / particles hit the walls harder
5. Therefore the pressure increases / greater overall force on the walls increases pressure

## Key terms

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

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-what-happens-to-the-pressure-ef50900a) · Published by Druglandscape Ltd.