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Atoms and Ions
Electricity from chemicals
A simple electric cell (battery) can be made by immersing 2 different metals in an electrolyte (an aqueous solution of an ionic compound) and connecting them with a conducting wire. A current flows through the wire.
At the anode: The zinc metal is oxidized. It loses electrons and Zn2+ ions go into solution.
At the cathode: The copper ions (Cu2+) in solution are reduced. They accept electrons are are depositied as atoms of copper onto the cathode.
The migration of electrons causes an electric curent to flow from the anode to the cathode. The a reading on the voltmeter shows that chemical energy has been converted into electrical energy.
Electrolysis is the breakdown of a substance by electricity. You will have seen evidence of this in the experiment where aqueous solutions of ionic compounds conduct electricity.
Electrolytes are compounds which do not conduct electricity when solids, but do when molten or in aqueous solution.
Examples: Ionic compounds. The ions are free to move and hence carry electric charge.
As you can see above there is a flow of electrons from the negative to the positive.
The ions carry the electric charge through the solution to complete the circuit.
Electrolysis of Copper II Sulfate solution
Oxygen gas is liberated at the anode
Copper metal is plated onto the carbon cathode
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