# Explain, using the kinetic model of an ideal gas, why two identical containers holding the same mass of gas but at different temperatures exert different pressures on their walls, and identify which container exerts the greater pressure.

> IB DP Physics Higher Level (2023 syllabus) — B.3 Gas laws · Explain · 4 marks

> Container A holds a fixed mass of ideal gas at 300 K. An identical container B holds the same mass of the same ideal gas at 600 K. Both containers have rigid walls and the same volume.

## Mark scheme (4 marks)

1. At higher temperature, gas molecules have greater average kinetic energy / move faster on average.
2. Faster-moving molecules exert a greater force per collision on the container walls.
3. Molecules also collide with the walls more frequently (per unit area per unit time) at higher temperature.
4. Container B (at 600 K) exerts the greater pressure because pressure is proportional to absolute temperature at constant volume and fixed amount of gas (Gay-Lussac's / pressure law).

## Key terms

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

## Related

- [Revision notes for IB DP Physics 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-using-the-kinetic-model-of-2ca77338) · Published by Druglandscape Ltd.