# Exothermic reaction

A reaction that gives out energy to the surroundings, usually as heat, so the temperature goes up.

Chemistry (school) · Part 04: Chemical reactions · Card 5 of 9 · Last updated 2026-10-19

## Analogy

Like a campfire. It warms everything nearby.

## In practice

Burning fuels, neutralisation and hand warmers are exothermic.

## Practice

### Flashcards

- **Is an energy-releasing reaction exothermic or endothermic?** Exothermic. The temperature of the surroundings rises.

## Questions people ask

### What are everyday examples of exothermic reactions?

Burning fuels such as gas or petrol, the reaction of acids with alkalis, rusting, and the respiration that keeps your body warm. Hand warmers and self-heating food cans also use exothermic reactions. They give out energy, which warms the surroundings.

### Why does an exothermic reaction release energy?

Breaking bonds in the reactants takes in energy, while making bonds in the products gives out energy. In an exothermic reaction, more energy is released making the new bonds than was needed to break the old ones. The extra energy leaves as heat.

## Related concepts

- [Endothermic reaction](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-4/chemistry-school-part-4-concept-6)

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