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Chapter 22
Revise Water
| Question | Answer |
|---|---|
| Is water a compound or an element? | A compound. |
| What elements make water? | Hydrogen and Oxygen. |
| How can you test a substance to see if it is water? | Copper sulphate anhydrous will turn blue in the presence of water. |
| What is the freezing point of water? | 0°C |
| What is the boiling point of water? | 100°C |
| What is the density of water? | 1g/cm2 |
| Why does ice float on water? | Ice is less dense than water. |
| Water is a good solvent. Why is this important? | We can use it to dissolve many different chemicals in it to make different compounds |
| What is the purest form of water? | Distilled, deionised water. |
| What is hard water? | Hard water is water that does not easily form a lather with sop. |
| What is soft water? | Soft water forms a lather easily with water. |
| What compounds are found in hard water? | Calcium carbonate. Calcium Hydrogen Carbonate, |
| When you boil water what do you remove? | Calcium Hydrogen carbonate. |
| How does an ion exchange resin get rid of hardness in water? | Using an anion exchange resin it replaces the calcium ions with sodium ions. |