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• Super Challenge:

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Key Questions:

1. When is electrolysis used to extract metals from their ores?
   • Metals can be extracted from molten compounds using electrolysis. Electrolysis is used if the metal is too reactive to be extracted by reduction with carbon or if the metal reacts with carbon.
2. What is the main drawback of using electrolysis to extract metals?
   • The main drawback of using electrolysis to extract metals is that a large amount of Energy is used to melt the compounds and to produce the electrical current.
3. How is aluminium extracted from its metal ore (aluminium oxide)?
   • Aluminium is manufactured by the electrolysis of a molten mixture of aluminium oxide and cryolite using carbon as the positive electrode (anode).
4. Why is a mixture used as the electrolyte in electrolysis?
   • A mixture is used as the electrolyte in electrolysis as the atoms are not chemically bonded they can be separated.
5. Why does the positive electrode (the anode) need to be replaced regularly?
   • Oxygen forms at the positive electrodes (anodes). This oxygen reacts with the carbon of the positive electrodes, forming carbon dioxide, and they gradually burn away.
6. (HT)What are the missing reactants and products of the half equation shown below: Mg2 ___--> _____
   • (HT) Mg2 2e- --> Mg