Electrolysis of Copper
Text Reference: Oxford Insight 10 pg. 155 Experiment 4.1.4 Electrolysis
Watch the video “Yr 10 Electrolysis of Copper Demo” and answer the questions below.
Submit your finished work on CANVAS.
1. What evidence was there that copper was formed in the reaction?
Copper was seen to form on the cathode, no matter what it was made of: graphite or
nickel. This was observed through the thin, visible layer of copper forming on the
cathode, which could even be taken off by some sand paper.
2. Is this an exothermic or endothermic process? Explain your choice.
Electrolysis is always endothermic, as energy is being inputted into the solution in
form of electricity.
3. Considering the structure of copper sulfate, describe the:
a. Role of water in the process.
Copper sulphate by itself is a solid powder, and the role of water is to make it liquid and into
a solution, making electrolysis possible. Copper sulfate is also more reactive and unstable by
itself, and when dissolved in a solution, it is safer and easier to work with.
b. Role of the electric circuit.
The electric circuit is needed for the electrolysis, providing the anode and the cathode,
attracting each ion. The circuit here breaks apart the Cu2+ to the cathode, and the SO42- to the
anode.
c. Reason that copper was only found on one of the carbon electrodes.
The copper was found only on the negatively charged electrode, as the copper ion was
positively charged, and opposite charges attract.
d. Reason why copper was only found on one side of the electrode.
This is because the electric field was only strongest directly in between the two electrodes,
and not the long way around the electrodes.
4. Attempt to write a balanced chemical equation for the reaction that is taking
place with the two graphite electrodes, given that they were in a pure copper
sulfate aqueous solution.
CuSO4 Cu2+ + SO42- Cu2+ + SO2 + O2
Text Reference: Oxford Insight 10 pg. 155 Experiment 4.1.4 Electrolysis
Watch the video “Yr 10 Electrolysis of Copper Demo” and answer the questions below.
Submit your finished work on CANVAS.
1. What evidence was there that copper was formed in the reaction?
Copper was seen to form on the cathode, no matter what it was made of: graphite or
nickel. This was observed through the thin, visible layer of copper forming on the
cathode, which could even be taken off by some sand paper.
2. Is this an exothermic or endothermic process? Explain your choice.
Electrolysis is always endothermic, as energy is being inputted into the solution in
form of electricity.
3. Considering the structure of copper sulfate, describe the:
a. Role of water in the process.
Copper sulphate by itself is a solid powder, and the role of water is to make it liquid and into
a solution, making electrolysis possible. Copper sulfate is also more reactive and unstable by
itself, and when dissolved in a solution, it is safer and easier to work with.
b. Role of the electric circuit.
The electric circuit is needed for the electrolysis, providing the anode and the cathode,
attracting each ion. The circuit here breaks apart the Cu2+ to the cathode, and the SO42- to the
anode.
c. Reason that copper was only found on one of the carbon electrodes.
The copper was found only on the negatively charged electrode, as the copper ion was
positively charged, and opposite charges attract.
d. Reason why copper was only found on one side of the electrode.
This is because the electric field was only strongest directly in between the two electrodes,
and not the long way around the electrodes.
4. Attempt to write a balanced chemical equation for the reaction that is taking
place with the two graphite electrodes, given that they were in a pure copper
sulfate aqueous solution.
CuSO4 Cu2+ + SO42- Cu2+ + SO2 + O2
