Specification Point 2.49:
Describe a test for the presence of water using anhydrous Copper (II) Sulfate
Chemical Test for Water
Test for Water using Anhydrous Copper (II) Sulfate
- Add liquid to anhydrous copper (II) sulfate
- Colour change is observed and recorded
- If liquid is water, the white powder will turn blue
- This is because hydrated copper (II) sulfate is formed and is a blue crystal
- Does not indicate whether water is pure
| CuSO4 (s) + 5H2O (l) → CuSO4.5H2O (s) |
Specification Point 2.50:
Describe a physical test to show whether a sample of water is pure
Physical Test for Pure Water
The process to measure the boiling point of water
- Boil the liquid and measure temperature as liquid starts to boil – its boiling point
- Freeze the liquid to measure its freezing point (same as melting point)
- Boiling point of pure water is 100°C
- Freezing point (melting point) of water is 0°C
- If either are increased or decreased water sample contains impurities
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Jamie got a First class degree in Chemistry from Oxford University before going on to teach chemistry full time as a professional tutor. He’s put together these handy revision notes to match the Edexcel IGCSE Chemistry specification so you can learn exactly what you need to know for your exams.
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