# Explain why the pressure of a fixed amount of gas increases when its temperature is raised at constant volume.

> IB DP Chemistry Standard Level (2023 syllabus) — S1.1 Introduction to the particulate nature of matter · Explain · 4 marks

## Mark scheme (4 marks)

1. Increasing temperature increases the average kinetic energy (or speed) of the gas particles.
2. Faster-moving particles collide with the walls of the container more frequently.
3. Each collision imparts greater force to the walls because the particles are moving faster (greater momentum change per collision).
4. Greater frequency and force of collisions with the walls results in higher pressure (since volume is constant, the number of particles and their confinement remain unchanged).

## Key terms

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

## Related

- [Revision notes for IB DP Chemistry Standard Level (2023 syllabus)](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/explain-why-the-pressure-of-a-65c5b40f) · Published by Druglandscape Ltd.