The copper(II) sulfate salt can be prepared using the filtration method.

Copper(II) oxide is added in excess to a fixed volume of dilute sulfuric acid.

Filter the mixture to remove the excess copper(II) oxide from the copper(II) sulfate solution.

The filtrate of copper(II) sulfate is then heated until saturated.

The saturated solution is allowed to cool so that crystals of copper(II) sulfate can be formed.

Filter the mixture to remove the excess water.

Wash the crystals with a little bit of cold distilled water and dry between two pieces of filter paper.