Calculations

Question 1

Explain water of crystallisation

Answer 1

• Hydrated crystals contain molecules of water trapped within the Crystal lattice
• the water can be evaporated by heating
• when all the water has been removed the Crystal is said to be anhydrous
• this process is called dehydration

Question 2

Method for water of crystallisation

Answer 2

1. Weigh an empty evaporating basin
2. Add 5 heaped spatula measures of copper(II) sulfate and weigh again
3. Gently heat and stir continually with a glass rod
4. When colour change is complete, stop heating, cool the basin and weigh it.
5. Heat the basin for a further 2 minutes until the mass is constant.