Final answer:
The extraction of copper from chalcocite involves roasting to form copper oxide, dissolving in nitric acid to form copper sulfate, and electrolytic refining to obtain pure copper. The chemical equations for these reactions are balanced and represent the transformation of copper sulfide into copper metal.
Step-by-step explanation:
Extraction of Copper from its Ore
The extraction of copper from its sulfide ore, such as chalcocite (Cu2S), involves several steps:
- Roasting: Chalcocite is roasted in the presence of oxygen to form copper and sulfur dioxide. The reaction can be represented by the balanced equation 2Cu2S(s) + 3O2(g) → 2Cu2O(s) + 2SO2(g).
- Dissolving in Nitric Acid: The copper is then reacted with nitric acid to form copper sulfate and nitrogen monoxide. The balanced equation is Cu(s) + 4HNO3(aq) → CuSO4(aq) + 2NO2(g) + 2H2O(l).
- Electrolytic Refining: Lastly, the process of electrolytic refining is used to further purify copper. In this step, impure copper is used as the anode, and pure copper acts as the cathode. An aqueous solution of copper sulfate is used as the electrolyte. When electricity is applied, copper ions from the solution are deposited onto the cathode, resulting in pure copper.
Another method involves the direct reaction of copper sulfide with nitric acid to oxidize sulfide to sulfate and reduce nitric acid to nitrogen monoxide, as shown in the balanced equation CuS(s) + 4HNO3(aq) → CuSO4(aq) + 4NO(g) + 2H2O(l).