Copper(II) sulfate pentahydrate can easily be produced by crystallization from solution as copper(II) sulfate, which is hygroscopic. When water is then added to the anhydrous compound, it turns back into the pentahydrate form, regaining its blue color. The pentahydrate form, which is blue, is heated, turning the copper sulfate into the anhydrous form which is white, while the water that was present in the pentahydrate form evaporates. It is used to demonstrate the principle of mineral hydration. Copper sulfate is often used to demonstrate an exothermic reaction, in which steel wool or magnesium ribbon is placed in an aqueous solution of CuSO 4. It is often used to grow crystals in schools and in copper plating experiments, despite its toxicity. Cu 2+ + 2e − → Cu (cathode), E ° cell = 0.34 VĬopper sulfate is commonly included in teenager chemistry sets and undergraduate experiments. For example, in a zinc/copper cell, copper ion in copper sulfate solution absorbs electron from zinc and forms metallic copper. In high school and general chemistry education, copper sulfate is used as an electrolyte for galvanic cells, usually as a cathode solution. Similarly treatment of such solutions with zinc gives metallic copper, as described by this simplified equation: CuSO 4 + Zn → Cu + ZnSO 4Ī further illustration of such single metal replacement reactions occurs when a piece of iron is submerged in a solution of copper sulfate: Thus, such solutions react with concentrated hydrochloric acid to give tetrachlorocuprate(II): The chemistry of aqueous copper sulfate is simply that of copper aquo complex, since the sulfate is not bound to copper in such solutions. It loses two water molecules upon heating at 63 ☌ (145 ☏), followed by two more at 109 ☌ (228 ☏) and the final water molecule at 200 ☌ (392 ☏). Chemical properties Ĭopper(II) sulfate pentahydrate decomposes before melting. Four types of crystal size are provided based on its usage: large crystals (10–40 mm), small crystals (2–10 mm), snow crystals (less than 2 mm), and windswept powder (less than 0.15 mm). Anhydrous copper sulfate is 39.81% copper and 60.19% sulfate by mass, and in its blue, hydrous form, it is 25.47% copper, 38.47% sulfate (12.82% sulfur) and 36.06% water by mass. Ĭommercial copper sulfate is usually about 98% pure copper sulfate, and may contain traces of water. Copper sulfate can also be produced by slowly leaching low-grade copper ore in air bacteria may be used to hasten the process. For laboratory use, copper sulfate is usually purchased.
Preparation of copper(II) sulfate by electrolyzing sulfuric acid, using copper electrodesĬopper sulfate is produced industrially by treating copper metal with hot concentrated sulfuric acid or copper oxides with dilute sulfuric acid.
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