ELECTROLYSIS

Decomposition using an electric current

Electrolysis Cell

Battery – provides power to start reaction Wires – carry the current Electrodes – carry the electric current into the

electrolyte, does not react Cathode – negative electrode, attracts positive

ions Anode – positive electrode, attracts negative ions Electrolyte – molten ionic salt, is decomposed by

the current

Electrolysis of molten lead bromide

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Electrolysis of molten lead bromide

Lead bromide = lead + bromine Fume cupboard – toxic bromine fumes Carbon electrodes Heated to melt salt – allows ions to move Silver beads of lead formed at the cathode

(-) Orange fumes of bromine form at the anode

(+)

Extraction of aluminium

Extraction of aluminium

Aluminium oxide = aluminium + oxygen Cryolite is added to reduce the melting point of

aluminium oxide Carbon electrodes are used Aluminium metal is formed at the cathode Oxygen gas is formed at the anode Oxygen reacts with the carbon anode wearing it

away, the anode has to be replaced

Purification of Copper

Purification of Copper

Impure copper is placed on the anode (+) Pure copper is placed on the cathode (-) Copper sulphate solution is the electrolyte No colour change occurs in the electrolyte