Electrolysis- extracting metals

• 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 purpose of reducing metal oxides?

  To isolate the pure metal
• How does carbon reduce metal oxides?

  Carbon displaces the metal to form pure metal
• Which metals can be reduced with carbon?

  Zinc, iron, and copper
• Why is electrolysis more expensive than reduction with carbon?

  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?

  It is solid and ions are fixed in place
• What must be done to aluminium oxide before electrolysis?

  It must be melted into a molten state
• What is the purpose of mixing aluminium oxide with cryolite?

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

  Over 2000 degrees Celsius
• What equipment is needed for 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 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" stand for?

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

  Aluminium oxide forms aluminium and oxygen
• What are the steps to prepare aluminium oxide for electrolysis?

  1. Purify aluminium oxide from bauxite
  2. Mix with cryolite
  3. Melt to form molten aluminium oxide
• What occurs at each electrode during electrolysis of aluminium oxide?

  • Anode: Oxygen ions lose electrons, form oxygen
  • Cathode: Aluminium ions gain electrons, form aluminium
• What are the energy requirements for electrolysis?

  • High energy needed to melt aluminium oxide
  • Continuous energy required for electrolysis process
• What is the significance of the melting point of aluminium oxide?

  • It must be over 2000 degrees Celsius to melt
  • High melting point necessitates energy-intensive processes
• What is the role of cryolite in the electrolysis process?

  • Lowers the melting point of aluminium oxide
  • Reduces energy consumption during electrolysis
• What are the implications of using electrolysis for metal extraction?

  • Expensive due to high energy requirements
  • Necessary for extracting more reactive metals