electrolysis

• ELECTROLYSIS P1 - what is electrolysis?


  the process of using electricity to extract elements from a compound.
• ELECTROLYSIS P1 - what is the name of the positive electrode?

  anode
• ELECTROLYSIS P1 - what is the name of the negative electrode?

  cathode
• ELECTROLYSIS P1 - what is an electrolyte?


  a liquid or solution that contains ions and so can conduct electricity.
• ELECTROLYSIS P1 - where are metals formed?

  cathode
• ELECTROLYSIS P1 - where are non-metals formed?

  anode
• ELECTROLYSIS P1 - how can ionic substances be electrolysed?


  by melting or dissolving them, and then passing a direct current through them.
• ELECTROLYSIS P1 - why can solid ionic substances not be electrolysed?


  they do not conduct electricity, or the ions cannot move.
• ELECTROLYSIS P1 - in the electrolysis of solutions, when is the metal not produced at the cathode?


  when the metal is more reactive than hydrogen.
• ELECTROLYSIS P1 - in the electrolysis of a metal halide solution, what Is produced at the anode?


  halogen gas.
• ELECTROLYSIS P1 - in the electrolysis of a metal sulphate solution, what is produced at the anode?


  oxygen
• ELECTROLYSIS P1 - what is the half equation for the ionisation of water?


  H2O --> H+ + OH-
• ELECTROLYSIS P1 - what metals are extracted from ionic compounds by using electrolysis?


  metals that are more reactive than carbon.
• ELECTROLYSIS P1 - in the electrolysis of aluminium oxide, why is the aluminium oxide mixed with cryolite?


  to lower the melting point
• ELECTROLYSIS P1 - in the electrolysis of aluminium oxide, what are the anodes made of?


  graphite
• ELECTROLYSIS P1 - in the electrolysis of aluminium oxide, why do the anodes need to be replaced?


  they react with the oxygen being formed.
• ELECTROLYSIS P1 - what can you remember to remember which electrode is which?

  PANIC - positive anode negative is cathode.
• ELECTROLYSIS P1 - what happens at the cathode?


  the positive metal ions are attracted to the cathode, where they will gain electrons to form the pure metal.
• ELECTROLYSIS P1 - what happens at the anode?


  the negative ions are attracted to the anode, where they will lose electrons and become the pure non-metal.