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extr. aluminium
Chemistry
Question | Answer |
---|---|
the electrodes are made out of what? | carbon/graphite |
the electrolyte (solution in which electricity passes through) is what? | aluminium oxide, dissolved in molten cyrolite. |
Why is the aluminium dissolved in molten cryolite? | Because the melting point of aluminium oxide needs to be reduced, without it, the melting point would be too high. It also makes it a better conductor of electricity. |
What's the main ore of aluminium oxide? | Bauxite |
The Bauxite is firstly purified to produce what? | Aluminium oxide. |
What's the reaction at the cathode? | Al3+ + 3e- -> Al |
What happens to the product here? | The aluminium melts and collects at the bottom of the cell. Here it is tapped off. |
What's the reaction at the anode? | 2O2- -> O2 + 4e- |
What happens to some of the oxygen at the anode? | It reacts with the carbon on the electrode and forms CO2. This gradually burns the anode away, meaning they must be replaced frequently. |