# Hand warmers are an everyday example of an exothermic reaction. Explain, in terms of bond breaking and bond forming, why the temperature of the surroundings increases when a hand warmer is used.

> Eduqas GCSE Chemistry — C5 Energy changes · Explain · 4 marks

## Mark scheme (4 marks)

1. Energy is released when new bonds are formed in the products
2. Energy is taken in / supplied to break bonds in the reactants
3. The energy released from forming new bonds is greater than the energy needed to break existing bonds
4. This surplus / extra energy is transferred to the surroundings, causing the temperature to increase

## Key terms

- [exothermic reaction](https://www.gradenine.co.uk/glossary/exothermic-reaction)
- [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 Eduqas GCSE Chemistry](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/hand-warmers-are-an-everyday-example-970357fc) · Published by Druglandscape Ltd.