# A student uses paper chromatography to investigate two food colourings, X and Y. Food colouring X produces three spots and food colouring Y produces one spot. Explain what the chromatography results tell the student about the composition of each food colouring.

> AQA GCSE Chemistry (8462) — 4.8.2 Identification of common gases · Explain · 4 marks

## Mark scheme (4 marks)

1. Food colouring X is a mixture (not a pure compound)
2. Because it produces more than one spot / three spots indicate three different components/compounds are present
3. Food colouring Y is a pure substance / a single compound
4. Because a pure compound produces a single spot (in all solvents) / one spot shows only one component is present

## Key terms

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

## 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-student-uses-paper-chromatography-to-efd1adbf) · Published by Druglandscape Ltd.