Electrolysis etc

• What does electrolysis mean?

  Splitting up with electricity
• What happens during electrolysis?

  Electricity is passed through a liquid or molten substance causing a chemical reaction
• What is the positive electrode in electrolysis called?

  Anode
• What is the negative electrode in electrolysis called?

  Cathode
• What occurs during the electrolysis of molten ionic solids?

  • Positive ions are attracted to the cathode
  • Negative ions are attracted to the anode
  • Electrons are transferred, causing ions to lose or gain electrons
  • Ions are reduced or oxidised to form atoms or molecules
  • Atoms or molecules form the elements
• How are metals extracted from their ores using electrolysis?

  By heating the metal ore with carbon to high temperatures
• What happens to the molten metal after electrolysis?

  The molten metal is attracted to the cathode
• What forms at the anode after electrolysis?

  Oxygen is attracted to the anode and forms oxygen molecules
• What is the half equation at the negative electrode?

  2H+ + 2e- > H2
• What is an example of electrolysis in metal extraction?

  The extraction of aluminium from bauxite
• What factors affect the electrolysis of aqueous solutions?

  1. Easier to discharge ions from water than solute

  • Less reactive metal ions: water discharged at cathode
  • More reactive metal ions: metal discharged at cathode
  • Copper or silver ions preferentially discharged

  1. Copper(II) chloride (CuCl₂) contains:

  • Copper metal ions (Cu²⁺)
  • Chloride ions (Cl^-)
  • Oxygen and water produced at the anode
• What is produced at the anode during the electrolysis of copper(II) chloride?

  Oxygen and water are produced
• How can you test the products of electrolysis?

  • Hydrogen: makes a 'squeaky pop' with a lighted splint
  • Chlorine: bleaches damp litmus paper, turning it white
  • Oxygen: will relight a glowing splint
• What do half equations show in electrolysis?

  The reactions at the electrodes
• What is important to remember about half equations?

  Make sure the electrons balance