A campsite uses filtered river water to produce drinking water. The water must contain fewer than 5 harmful microbes per 100 cm³ after treatment.
The campsite compares two methods of sterilising the water.
| Method | Mean number of harmful microbes after treatment per 100 cm³ | Sterilising chemical added in mg per dm³ | Electrical energy used in kWh per 1000 dm³ |
|---|---|---|---|
| Chlorine | 1 | 0.50 | 0.05 |
| Ultraviolet light | 2 | 0.00 | 0.30 |
Evaluate which method the campsite should use to sterilise the water.
87 exam-style questions on AQA GCSE Chemistry 10.1 Using the Earth's resources and obtaining potable water, covering 10.1.1 Using the Earth's resources and sustainable development, 10.1.2 Potable water, 10.1.3 Waste water treatment, and 10.1.4 Alternative methods of extracting metals. Each one has a worked solution and a mark scheme showing where the marks go.