# A water company routinely monitors the quality of drinking water supplied to homes. Chemists at the treatment plant use instrumental methods of analysis to check for trace amounts of metal ions and organic contaminants in water samples. Explain why instrumental methods are used for this purpose rather than traditional chemical tests.

> WJEC A-Level Chemistry (Wales) — 2.8 Instrumental analysis · Explain · 5 marks

> Water companies are legally required to ensure drinking water meets strict safety standards, including limits on certain metal ions measured in parts per million (ppm).

## Mark scheme (5 marks)

1. Instrumental methods are more sensitive than traditional chemical tests
2. Instrumental methods can identify/detect very small quantities (traces) of substances that traditional tests cannot
3. Instrumental methods give faster/quicker results than traditional chemical tests
4. Instrumental methods are more accurate/reliable than traditional chemical tests
5. Instrumental methods can analyse many samples or handle large numbers of samples automatically/at the same time

## Key terms

- [instrumental methods](https://www.gradenine.co.uk/glossary/instrumental-methods)
- [trace amounts](https://www.gradenine.co.uk/glossary/trace-amounts)
- [traditional chemical tests](https://www.gradenine.co.uk/glossary/traditional-chemical-tests)

## Related

- [Revision notes for WJEC A-Level 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-water-company-routinely-monitors-the-a03a1f9f) · Published by Druglandscape Ltd.