# State and explain why salt dissolved in water is classified as a mixture rather than a compound.

> Cambridge International IGCSE Chemistry (0620) — 2.1 Elements, compounds and mixtures · State and explain · 4 marks

> Sea water contains sodium chloride (common salt) dissolved in water. A student claims that salt water is a compound because it contains more than one substance.

## Mark scheme (4 marks)

1. The composition (ratio of salt to water) can vary / the proportions of the substances are not fixed
2. The substances are not chemically combined / no chemical bonds form between salt and water
3. The salt and water can be separated by a physical method / properties of the individual substances are retained
4. A compound has a fixed composition / substances are chemically combined in a compound, which is not the case here

## Key terms

- [mixture](https://www.gradenine.co.uk/glossary/mixture)
- [compound](https://www.gradenine.co.uk/glossary/compound)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "State and 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/state-and-explain-why-salt-dissolved-84f71a97) · Published by Druglandscape Ltd.