# Explain why a fixed mass of gas exerts a greater pressure on the walls of its container when the temperature of the gas is increased at constant volume.

> IB DP Chemistry Higher 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 container walls more frequently.
3. Each collision transfers greater momentum / force to the wall because particles are moving faster.
4. Pressure is the force per unit area exerted on the walls, so both greater frequency and greater force of collisions result in increased pressure.

## 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 Higher 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-a-fixed-mass-of-8312d3df) · Published by Druglandscape Ltd.