# A student carries out paper chromatography on two black inks, Ink A and Ink B, using the same solvent. Ink A produces a single spot and Ink B produces three separate spots. Explain what these results tell the student about the two inks, and describe the role of the mobile phase and the stationary phase in separating the components of Ink B.

> WJEC GCSE Chemistry (Wales) — 1.4 The ever-changing Earth · Explain · 4 marks

## Mark scheme (4 marks)

1. Ink A is a pure substance because it produces only one spot
2. Ink B is a mixture because it produces more than one spot / contains more than one substance
3. The mobile phase (solvent) carries the components of Ink B up the paper
4. The components separate because they have different solubilities in the mobile phase / travel different distances depending on how soluble they are

## Key terms

- [mobile phase](https://www.gradenine.co.uk/glossary/mobile-phase)
- [stationary phase](https://www.gradenine.co.uk/glossary/stationary-phase)
- [paper chromatography](https://www.gradenine.co.uk/glossary/paper-chromatography)

## Related

- [Revision notes for WJEC GCSE Chemistry (Wales)](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-carries-out-paper-chromatography-914eef6f) · Published by Druglandscape Ltd.