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Extraction of Metals

Extraction of Copper - Purification by Electrolysis.

High purity copper is needed to make electrical wires.

The anode is a block of impure copper.
The cathode is a thin piece of pure copper.
The electrolyte is copper sulfate.

When electricity is passed through the cell
copper is dissolved at the anode by oxidation
and Cu²⁺ ions go into solution.

Cu_(s)  -  2e^-       Cu²⁺_(aq)

At the cathode, copper is deposited by reduction.

Cu²⁺_(aq)  +  2e^-       Cu_(s)

As copper ions move from the anode to the cathode
the anode gets smaller as the cathode gets bigger.
This is a redox reaction (continued).

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