How to obtain pure, dry copper(II) sulphate crystals?
Since it is available commercially, copper sulfate is usually purchased and not prepared in the laboratory. It can be made by the action of sulfuric acid on a variety of copper(II) compounds, for example copper(II) oxide; this oxide can be generated with the addition of hydrogen peroxide to the acid. It may also be prepared by electrolyzing sulfuric acid, using copper electrodes. The problem with copper sulphate is that it is hygroscopic. So once you have your blue crystals, you need to heat them up in a test tube untill the turn white. This is then Pure Dry Copper II sulphate. However, they will quickly absorb water from the surroundings turning blue again.
