# A pharmaceutical company produces two batches of a painkiller. Batch 1 is described as a pure substance and Batch 2 is described as a mixture. Explain how melting point data could be used to distinguish between the two batches, and what the results would show about the purity of each batch.

> WJEC GCSE Chemistry (Wales) — 1.2 Atomic structure and the periodic table · Explain · 4 marks

## Mark scheme (4 marks)

1. A pure substance has a sharp (specific/precise) melting point
2. A mixture melts over a range of temperatures
3. Batch 1 (the pure substance) would produce a sharp/single melting point, confirming it is pure
4. Batch 2 (the mixture) would melt over a range of temperatures, confirming it is impure

## Key terms

- [pure substance](https://www.gradenine.co.uk/glossary/pure-substance)
- [mixture](https://www.gradenine.co.uk/glossary/mixture)
- [melting point data](https://www.gradenine.co.uk/glossary/melting-point-data)

## 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-pharmaceutical-company-produces-two-batches-7988bbe1) · Published by Druglandscape Ltd.