Electrolysis - Extracting Metals

• What process is used to extract reactive metals from their oxides?

  Electrolysis
• Why do metals often exist as oxides?

  They react with oxygen in the environment
• What is the cheap method to reduce metal oxides?

  Reduction with carbon
• Which metals can be reduced using carbon?

  Zinc, iron, and copper
• What is the main drawback of using electrolysis for metal extraction?

  It requires a lot of energy
• What is the process of electrolysis?

  Separating ionic compounds into pure elements
• What is required for electrolysis to work?


  The ions must be able to move
• What is the state of aluminium oxide at room temperature?

  Solid
• What is the ore from which aluminium oxide is extracted?

  Bauxite
• What is the purpose of mixing aluminium oxide with cryolite?

  To lower the melting point
• What is the melting point of aluminium oxide?

  Over 2000°C
• What is produced at the cathode during electrolysis of aluminium oxide?

  Molten aluminium
• What is the half equation for the reaction at the cathode?

  Aluminium ions gain electrons to form aluminium
• What does oxidation mean in terms of electrons?

  Loss of electrons
• What does reduction mean in terms of electrons?

  Gain of electrons
• What is the overall equation for the electrolysis of aluminium oxide?

  Aluminium oxide forms aluminium and oxygen
• What is the state of aluminium and oxygen produced in electrolysis?

  Aluminium is liquid, oxygen is gas
• What are the steps to prepare aluminium oxide for electrolysis?

  1. Purify aluminium oxide from bauxite
  2. Mix with cryolite
  3. Melt to make it molten
• What happens to the ions during electrolysis of aluminium oxide?

  • Oxygen ions are attracted to the anode
  • Aluminium ions are attracted to the cathode
  • Electrons are transferred at both electrodes
• What are the products of electrolysis of aluminium oxide?

  • Aluminium (liquid)
  • Oxygen (gas)
• What is the significance of the melting point in electrolysis?

  • Must be molten for ions to move
  • High melting point requires energy
• What is the role of cryolite in the electrolysis process?

  • Lowers the melting point of aluminium oxide
  • Makes the process more energy efficient
• What is the importance of the electrodes in electrolysis?

  • Conduct electricity
  • Facilitate the transfer of electrons
• What is the role of the power source in electrolysis?

  • Provides electric current for the reaction
  • Completes the circuit for electron flow
• What is the significance of the overall equation in electrolysis?

  • Represents the complete reaction
  • Shows reactants and products