4.8 Electrolysis 2 - Aluminium Oxide

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

  Electrolysis
• Why do metals often exist as oxides?

  Because they react with oxygen in the environment
• What is the cheap method to remove oxygen from metal oxides?

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

  Metals less reactive than carbon, like zinc, iron, and copper
• What is the main drawback of using electrolysis for metal extraction?

  It requires a lot of energy
• What is the role of an electrolyte in electrolysis?

  To allow ions to move freely
• Why can't aluminium oxide be used directly in electrolysis?

  Because it is solid and the ions are fixed in place
• What must be done to aluminium oxide before electrolysis can occur?

  It must be melted into a molten state
• What mineral is mixed with aluminium oxide to lower its melting point?

  Cryolite
• What is the melting point of aluminium oxide?

  Over 2000 degrees Celsius
• What equipment is needed for the electrolysis of molten aluminium oxide?

  A beaker, electrodes, and a power source
• What are the two types of electrodes used in electrolysis?

  Anode and cathode
• What happens to oxygen ions at the anode during electrolysis?

  They lose electrons and form oxygen atoms
• What is produced at the cathode during the electrolysis of aluminium oxide?

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

  Oxygen ions form oxygen atoms plus electrons
• What is the half equation for the reaction at the cathode?

  Aluminium ions combine with electrons to form aluminium
• What does the mnemonic "oil rig" help remember?

  Oxidation is loss of electrons, reduction is gain of electrons
• What is the overall equation for the electrolysis of aluminium oxide?

  Aluminium oxide liquid forms aluminium liquid and oxygen gas
• What are the steps involved in the electrolysis of aluminium oxide?

  1. Purify aluminium oxide from bauxite
  2. Mix with cryolite to lower melting point
  3. Melt the mixture to create molten aluminium oxide
  4. Set up electrolysis equipment with electrodes and power source
  5. Conduct electrolysis to produce aluminium and oxygen
• What are the roles of the anode and cathode in the electrolysis of aluminium oxide?

  • Anode: Positive electrode where oxidation occurs (oxygen ions lose electrons)
  • Cathode: Negative electrode where reduction occurs (aluminium ions gain electrons)
• What are the characteristics of the electrolysis process?

  • Requires an electrolyte
  • Involves movement of ions
  • Produces pure elements from ionic compounds
  • Involves oxidation and reduction reactions
• What are the products of the electrolysis of aluminium oxide?

  • Aluminium (liquid)
  • Oxygen (gas)