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.
Electrolysis cell for the purification of copper
Edexcel GCSE Chemistry Notes
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