# A hand warmer is used by a person on a cold day. When the hand warmer is activated, it releases energy to the surroundings. Explain, in terms of bond breaking and bond forming, why the reaction in the hand warmer causes the temperature of the surroundings to increase.

> AQA GCSE Chemistry (8462) — 4.5.1 Exothermic and endothermic reactions · Explain · 4 marks

## Mark scheme (4 marks)

1. Energy is required / supplied to break bonds in the reactants
2. Energy is released when new bonds are formed in the products
3. The energy released from forming bonds is greater than the energy needed to break bonds
4. So overall energy is transferred to the surroundings, causing the temperature of the surroundings to increase

## Key terms

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

## Related

- [Revision notes for AQA GCSE Chemistry (8462)](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-hand-warmer-is-used-by-f15cf2fa) · Published by Druglandscape Ltd.