A student planned to make copper sulfate crystals from excess copper oxide and dilute sulfuric acid.
The equation for the reaction is:
CuO(s) + H,SO (aq) -, CuSO (aq) + H20(1)
This is the method used.
1. Add 25 cm° of dilute sulfuric acid to a conical flask.
2. Gently warm the dilute sulfuric acid.
3. Add excess copper oxide to the dilute sulfuric acid.
4. Stir the mixture.
5. Heat to evaporate all the water from the mixture.
Suggest two improvements to the method
Explain why each improvement is needed.

A student plans a method to prepare pure crystals of copper sulfate.
The student's method is:
1. Add one spatula of calcium carbonate to dilute hydrochloric acid in a beaker.
2. When the fizzing stops, heat the solution with a Bunsen burner until all the liquid is gone.
The method contains several errors and does not produce copper sulfate crystals.
Explain the improvements the student should make to the method so that pure crystals of copper sulfate are produced.