# Cold packs are used by athletes to treat injuries. When a cold pack is activated, an endothermic reaction occurs inside it. Explain, using the concept of activation energy and a reaction profile, how a catalyst would affect this endothermic reaction, and describe the overall energy change that would be shown on the reaction profile.

> OCR A-Level Chemistry A (H432) — 5.2 Energy · Explain · 5 marks

> Cold packs contain chemicals that undergo an endothermic reaction when mixed. Athletes press the pack to activate it and apply it to an injury to reduce swelling. A sports scientist suggests that adding a catalyst to the cold pack would make it work more quickly.

## Mark scheme (5 marks)

1. A catalyst provides a different reaction pathway with a lower activation energy
2. A larger proportion of particles will have at least the activation energy, so the rate of reaction increases
3. The catalyst does not change the overall energy change of the reaction
4. On the reaction profile, the products have more energy than the reactants for an endothermic reaction
5. The cold pack absorbs energy from the surroundings / the surroundings (skin/injury) feel cold because energy is taken in by the reaction

## Key terms

- [activation energy](https://www.gradenine.co.uk/glossary/activation-energy)
- [catalyst](https://www.gradenine.co.uk/glossary/catalyst)
- [reaction profile](https://www.gradenine.co.uk/glossary/reaction-profile)
- [endothermic](https://www.gradenine.co.uk/glossary/endothermic)

## Related

- [Revision notes for OCR A-Level Chemistry A (H432)](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/cold-packs-are-used-by-athletes-633a908d) · Published by Druglandscape Ltd.