Write a half equation, including state symbols, for copper reacting at the anode.
Use data from the Data Booklet to explain why silver stays as the metal.
Use data from the Data Booklet to predict what happens to the nickel at the anode.
Write a half equation, including 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 gradually fades as electrolysis continues.
Calculate the following, using appropriate data from the Data Booklet: number of moles of copper produced at the cathode; number of moles of electrons needed to produce this copper; 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 produced. Use data from the Data Booklet to explain why nickel can be purified by an electrolysis method similar 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.