Electrolysis of Copper Sulfate Solution

Specification Point 3.30:
  • Explain the formation of the products in the electrolysis of copper sulfate solution, using copper electrodes, and how this electrolysis can be used to purify copper.
  • The electrolysis of CuSO4 using graphite rods produces oxygen and copper.
  • By changing the electrodes from graphite to pure and impure copper, the products can be changed at each electrode.
  • Electrolysis can be used to purify metals by separating them from their impurities.
  • In the set-up, the impure metal is always the anode, in this case the impure copper.
  • The cathode is a thin sheet of pure
  • The electrolyte used is an aqueous solution of a soluble salt of the pure metal at the anode, e.g: CuSO4.
  • Copper atoms at the anode lose electrons, go into solution as ions and are attracted to the cathode where they gain electrons and form now purified copper atoms.
  • The anode thus becomes thinner due to loss of atoms and the impurities fall to the bottom of the cell as sludge.
  • The cathode gradually becomes thicker.

Refining Copper, Edexcel GCSE Chemistry

Electrolysis cell for the purification of copper

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.