# Explain why instrumental methods of analysis are often preferred over traditional chemical tests when identifying substances in a sample. In your answer, refer to the speed, sensitivity and accuracy of instrumental methods.

> Eduqas A-Level Chemistry — 2.8 Instrumental analysis · Explain · 5 marks

> Scientists working in a forensic laboratory need to identify very small traces of unknown substances found at a crime scene. They must produce reliable results quickly.

## Mark scheme (5 marks)

1. Instrumental methods are faster / give results more quickly than traditional chemical tests
2. Instrumental methods can detect very small / tiny amounts (traces) of a substance — they are more sensitive
3. Instrumental methods are more accurate / more reliable than traditional tests
4. Instrumental methods can identify substances that traditional chemical tests cannot distinguish between / can identify mixtures of substances
5. Instrumental methods produce data that can be stored / compared to a database / reference library to identify an unknown substance

## Key terms

- [instrumental methods](https://www.gradenine.co.uk/glossary/instrumental-methods)
- [sensitivity](https://www.gradenine.co.uk/glossary/sensitivity)
- [accuracy](https://www.gradenine.co.uk/glossary/accuracy)

## Related

- [Revision notes for Eduqas A-Level Chemistry](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/explain-why-instrumental-methods-of-analysis-314900c4) · Published by Druglandscape Ltd.