Electrolysis: purifying copper
I can investigate what happens when a solution of copper sulfate is electrolysed with copper electrodes.
Electrolysis: purifying copper
I can investigate what happens when a solution of copper sulfate is electrolysed with copper electrodes.
Lesson details
Key learning points
- Purification of copper involves using copper electrodes in an electrolyte.
- The electrolyte must contain the same ions, in solution, as the metal being purified by electrolysis.
- Measuring the mass change in the copper electrodes demonstrates the transfer of copper.
- Impurities in the anode do not transfer to the cathode, leading to pure copper deposition.
- Other uses for this technique include electroplating, where you would use multiple metals e.g. gold.
Common misconception
Pupils do not always appreciate the difference between using inert carbon electrodes and metal electrodes, which will take part in the reaction.
Provide pupils with the opportunity to investigate the electrolysis of copper sulfate with both inert electrodes and with copper electrodes and then compare the results.
Keywords
Pure - a single element or compound that is not mixed with any other substance
Anode - a positively charged electrode, in an electrolysis cell, to which the anions are attracted
Cathode - a negatively charged electrode, in an electrolysis cell, to which the cations are attracted
Electrolyte - a liquid or an aqueous salt solution that contains freely moving ions
Electroplating - a process that uses electricity to deposit a thin layer of metal onto the surface of another conductive object
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
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