# A perfume manufacturer claims that a particular fragrance ingredient is a pure substance. Explain how melting point data could be used to evaluate whether the fragrance ingredient is pure or a mixture, and describe what the results would show in each case.

> OCR GCSE Chemistry A: Gateway Science (J248) — C2.1 Purity and separating mixtures · Explain · 4 marks

> A perfume manufacturer produces fragrance ingredients. Quality control staff need to check the purity of one ingredient before it is added to a new perfume.

## Mark scheme (4 marks)

1. A pure substance has a sharp/precise melting point (melts at one specific temperature)
2. A mixture melts over a range of temperatures (rather than at one fixed temperature)
3. The measured melting point of the pure substance would match the known/expected melting point for that substance
4. If the ingredient is a mixture, the melting point would be lower than/different from the expected value for the pure substance

## Key terms

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

## Related

- [Revision notes for OCR GCSE Chemistry A: Gateway Science (J248)](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-perfume-manufacturer-claims-that-a-902e9d77) · Published by Druglandscape Ltd.