# Cold packs are used by athletes to treat injuries. When a cold pack is activated, a chemical reaction occurs inside that causes the pack to feel cold. Explain why the pack feels cold, using ideas about bond breaking and bond forming.

> Edexcel GCSE Chemistry (1CH0) — 7.2 Heat energy changes in chemical reactions · Explain · 4 marks

> Cold packs contain chemicals that react together when the pack is activated. Athletes press on the pack to start the reaction, and the surface of the pack rapidly drops in temperature.

## Mark scheme (4 marks)

1. The reaction taking place is endothermic
2. More energy is needed/absorbed to break bonds in the reactants than is released when new bonds form in the products
3. Energy is taken in from the surroundings (the pack / the athlete's skin)
4. This causes the temperature of the surroundings / the pack to decrease, so it feels cold

## Key terms

- [bond breaking](https://www.gradenine.co.uk/glossary/bond-breaking)
- [bond forming](https://www.gradenine.co.uk/glossary/bond-forming)

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](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-28878923) · Published by Druglandscape Ltd.