electrolysis of aluminium oxide

• What determines the method of metal extraction?

  The position of the metal on the reactivity series
• Why must higher placed metals be extracted using electrolysis?

  They are too reactive to be reduced by carbon
• How can lower placed metals be extracted?

  By heating with carbon which reduces them
• What is a major drawback of electrolysis for metal extraction?

  It requires large amounts of energy
• What is the main ore of aluminium?

  • Bauxite
  • Contains aluminium oxide
• Why can't aluminium be extracted by reduction using carbon?

  It is higher in the reactivity series than carbon
• What is the first step in extracting aluminium from bauxite?

  Bauxite is purified to produce aluminium oxide
• Why is aluminium oxide dissolved in molten cryolite?

  To lower the melting point and reduce energy costs
• What is the melting point of aluminium oxide?

  Over 2000°C
• What is the role of the electrolysis cell in aluminium extraction?

  It facilitates the electrolysis process for extraction
• What materials line the electrolysis cell?

  Steel and graphite
• What acts as the negative electrode in the electrolysis cell?

  The graphite lining of the cell
• Where is aluminium produced during electrolysis?

  At the cathode
• What is produced at the anode during aluminium extraction?

  Oxygen
• Why does the anode need to be replaced regularly?

  It reacts with oxygen to produce CO2
• What is the chemical reaction that occurs at the anode?

  C (s) + O2 (g) → CO2 (g)
• What is a major expense in the extraction process of aluminium?

  A lot of electricity is required