Purifying copper by electrolysis
Copper is purified by The decomposition (breakdown) of a compound using an electric current.. Electricity is passed through solutions containing copper compounds, such as copper sulfate. The The positive electrode during electrolysis. (positive A conductor used to establish electrical contact with a circuit. The electrode attached to the negative terminal of a battery is called a negative electrode, or cathode. The electrode attached to the positive terminal of a battery is the positive electrode, or anode.) is made from impure copper and the The negative electrode during electrolysis. (negative electrode) is made from pure copper.
Pure copper forms on the cathode. The slideshow shows how this works:
Image caption, Purifying copper by electrolysis
1. A beaker with pure and impure copper rods dipped into copper sulfate solution
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During electrolysis, the anode loses mass as copper dissolves, and the cathode gains mass as copper is deposited.
The slideshow shows what happens during the purification of copper by electrolysis:
Image caption, The purification of copper by electrolysis
1. Four Cu ions are attached to the rod on the right, and four Cu²+ ions are floating in the space between the rods
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