Electrolysis and extraction of aluminium

• What is the process of electrolysis used for?

  To break down electrolytes into elements
• What is an electrolyte?

  A substance that conducts electricity when molten or in solution
• Which metal is extracted from its ore using electrolysis?

  Aluminium
• What happens during electrolysis of molten ionic compounds?

  • Decomposition of compound occurs
  • Positively-charged ions move to the cathode
  • Negatively-charged ions move to the anode
  • Ions receive or lose electrons
• What is the negative electrode called during electrolysis?

  Cathode
• What occurs at the cathode during electrolysis?

  Positively-charged ions are reduced
• What is the positive electrode called during electrolysis?

  Anode
• What happens at the anode during electrolysis?

  Negatively-charged ions are oxidized
• What is the term for the breakdown of a compound using an electric current?

  Decomposition
• What are charged particles in electrolysis called?

  Ions
• What is the formula for lead(II) bromide?

  PbBr₂
• What ions does lead(II) bromide contain?

  Pb²⁺ and Br^-
• Why must a compound contain ions for electrolysis to occur?

  Because ions must be free to move
• What happens to ionic substances when they are dissolved in water?

  The ions become free to move
• What is the state of lead(II) bromide during electrolysis?

  It must be molten or dissolved
• What is produced when electricity is passed through molten lead(II) bromide?

  Lead and bromine
• What are the key components of electrolysis of molten ionic compounds?

  • Electric current is passed through electrolyte
  • Ions move towards respective electrodes
  • Reduction occurs at cathode
  • Oxidation occurs at anode
  • Products are formed from the breakdown of the electrolyte
• What is the process of electrolysis used for?

  To break down electrolytes to form elements
• What is one metal extracted using electrolysis?

  Aluminium
• What happens during the electrolysis of molten salts?

  • New substances form
  • Molten ionic compounds conduct electricity
  • Positive metal ions move to the cathode
  • Negative non-metal ions move to the anode
• What is the result of electrolysis of lead(II) bromide?

  Produces bromine and lead
• Why are carbon electrodes used in electrolysis?

  They have a high melting point and are inert
• What observations occur at the anode and cathode during electrolysis of lead(II) bromide?

  At the anode:

  • Bubbles of brown gas (bromine vapour)

  
  

  At the cathode:

  • Silvery liquid metal (lead)
• What is produced at the anode during the electrolysis of zinc chloride?

  Chlorine (Cl₂)
• What is produced at the cathode during the electrolysis of aluminium oxide?

  Aluminium (Al)
• How can the products of electrolysis be predicted?

  • Electrolytes split into their elements
  • Metal forms at the negative electrode
  • Non-metal forms at the positive electrode
• What is the chemical formula for aluminium oxide?

  Al2O3
• What is the chemical formula for zinc chloride?

  ZnCl₂
• What is an ionic compound?

  Formed by positive and negative ions
• What is the term used to describe a liquid substance formed by heating a solid?

  Molten
• What is the role of electrodes in electrolysis?

  To establish electrical contact with a circuit
• How do positive and negative ions behave during electrolysis?

  Positive ions move to the cathode, negative ions to the anode
• What are the products of electrolysis for zinc chloride and aluminium oxide?

  Zinc chloride (ZnCl₂):

  • Anode: Chlorine (Cl₂)
  • Cathode: Zinc (Zn)

  
  

  Aluminium oxide (Al₂O₃):

  • Anode: Oxygen (O₂)
  • Cathode: Aluminium (Al)
• What is the process of electrolysis used for?

  To break down electrolytes to form elements
• What can be predicted from a given electrolyte in electrolysis?

  The products of electrolysis
• Which metal is extracted from its ore using electrolysis?

  Aluminium
• What is a half-equation in electrolysis?

  • Shows what happens at one electrode
  • Represents electron transfer during reactions
• What is an electrode?

  A conductor for electrical contact
• What is the negative electrode called in electrolysis?

  Cathode
• What is the positive electrode called in electrolysis?

  Anode