Write a half equation, with state symbols, for the reaction of copper at the anode.
Use data from the Data Booklet to explain why silver remains as the metal.
Use data from the Data Booklet to predict what happens to the nickel at the anode.
Write a half equation, with state symbols, for the main reaction at the cathode.
Use data from the Data Booklet to explain why zinc is not deposited on the cathode.
Suggest why the blue colour of the electrolyte slowly fades as the electrolysis proceeds.
Calculate the following, using appropriate data from the Data Booklet: the number of moles of copper produced at the cathode; the number of moles of electrons needed to produce this copper; the number of moles of electrons that passed through the cell.
Hence calculate the percentage of the current through the cell that has been wasted in dissolving the impurities at the anode.
Nickel is often found in ores together with iron. After the ore is first reduced with coke, a nickel-iron alloy is formed. Use data from the Data Booklet to explain why nickel can be purified by a similar electrolysis method to the one used for copper, using an impure nickel anode, a pure nickel cathode, and nickel sulfate as the electrolyte. Explain what would happen to the iron during this process.