Extract Metals from Oxides

• What ore is aluminium extracted from via electrolysis?

  bauxite
• Why is cryolite used in the electrolysis of aluminium oxide?

  Aluminium oxide has a very high melting point so it would be very expensive to melt. Cryolite lowers the melting point of the aluminium oxide, therefore reducing the cost of the process
• In the electrolysis of molten aluminium oxide (Al₂O₃), which 2 ions would be present in the electrolyte?

  Al³⁻

  O²⁻
• In the electrolysis of molten aluminium oxide (Al₂O₃), what would form at the positive electrode (anode)?

  oxgen gas- O₂
• In the electrolysis of molten aluminium oxide (Al₂O₃), what would form at the negative electrode (cathode)?

  Molten alunimium- Al
• In the electrolysis of molten aluminium oxide (Al₂O₃),what would be the half equation for the reaction at the positive electrode (anode)?

  2O²⁻ -> O₂ + 4e⁻

• In the electrolysis of molten aluminium oxide (Al₂O₃), what would be the half equation for the reaction at the negative electrode (cathode)?

  Al³⁺ + 3e⁻ -> Al

• Write the overall balanced symbol equation for the separation of aluminium oxide during electrolysis


  2Al₂O₃—> 4Al + 3O₂

• In the electrolysis of molten aluminium oxide (Al₂O₃), are the Al³⁺ ions oxidised or reduced?


  reduced as they gain electrons
• In the electrolysis of molten aluminium oxide (Al₂O₃) are the O²⁻ ions oxidised or reduced?


  oxidised as they lose electrons
• Write the overall balanced symbol equation for the separation of aluminium oxide during electrolysis


  2Al₂O₃ -> 4Al + 3O₂