Activity 5.3 To obtain pure crystals of copper sulphate by the process of crystallization. Class 9

Activity 5.3 To obtain pure crystals of copper sulphate by the process of crystallization. Class 9

Activity 5.3

Aim: To obtain pure crystals of copper sulphate by the process of crystallization.

Materials Required: 1g Copper sulphate powder, Water, Beaker, Glass rod, Filter paper, Funnel, Burner (or heat source).

Procedure:

1. Take 100 Ml of water in a beaker and heat it gently.
2. Add 1g of copper sulphate powder and stir until no more dissolves (make a hot saturated solution).
3. Add 25ml of water to the beaker and add a drop of dilute sulfuric acid, heat the mixture while stirring continuosly.
4. Gradually add more copper sulfate until the solution becomes saturated, as in fig. (a)
5. Filter the solution to remove impurities, as in fig. (b)
6. Allow the clear solution to cool undisturbed, as in fig. (c)
7. After some time, blue crystals of copper sulphate will form.

Observation:

On cooling the hot saturated solution, large, shiny, well-shaped blue crystals of copper sulfate are formed.

Conclusion:

Crystallization is a useful method for the purification of solid and is based on the change in solubility with temperature.