Copper Sulfate from Copper Oxide and Dilute Sulfuric Acid

Copper sulfate is made industrially by dissolving copper oxides in dilute sulfuric acid (or copper metal in hot concentrated acid). CuO + H₂SO₄ → CuSO₄ + H₂O. From the solution it crystallises in its blue hydrous form, the pentahydrate, which is about 25% copper, 38% sulfate and 36% water by mass. Commercial copper sulfate is about 98% pure. It is used as a fungicide, for etching zinc, aluminium and copper printing plates, and to make ferrous sulfate.