# A sealed metal canister contains gas at room temperature. The canister is placed in boiling water and left until the gas inside reaches the same temperature as the water. Explain, using kinetic theory, why the pressure of the gas inside the canister increases.

> WJEC A-Level Physics (Wales) — 4.2 Kinetic theory and gases (A-Level only) · Explain · 5 marks

> A sealed metal canister contains gas at room temperature. When placed in boiling water, the pressure gauge on the canister shows a higher reading than before.

## Mark scheme (5 marks)

1. The gas particles move faster / have greater kinetic energy at higher temperature
2. The particles collide with the walls of the canister more frequently
3. Each collision exerts a greater force on the walls / collisions are harder / more forceful
4. The volume of the canister stays the same / cannot expand because it is sealed and rigid
5. More force per unit area on the walls means greater pressure / pressure increases because of increased force on the same area

## Key terms

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

## Related

- [Revision notes for WJEC A-Level Physics (Wales)](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-metal-canister-contains-gas-7e299622) · Published by Druglandscape Ltd.