electrolysis

• what is an electrode 


  solid conductor used in all electrolysis(usually made of metal or carbon)
• what is an anode 


  positive electrode
• what is a cathode


  negative electrode
• what is an electrolyte


  a liquid made of ions that conducts electricity
• what do you have to do if the molecule in electrolysis is insoluble and why is being insoluble a problem

  melt it to make it molten liquid as ions need to be free to move
• electrolysis only works when 


  the ions are free to move
• what is electrolysis 


  splitting up with electricity
• what is attracted to the positive electrodes 


  negative ions
• what is attracted to the negative electrodes 


  positive ions
• why do some ions have to discharge in pairs


  -only when an ion is diatomic do they have to discharge in pairs
• what is the acronym for diatomic elements

  I Have No Bright Or Clever Friends

  Iodine, Hydrogen, Nitrogen, Bromine, Oxygen, Chlorine, Fluoride
• give an example of diatomic elements discharging in pairs


  neutral oxygen atoms will combine to form O2 molecules and float away together
• how do ion usually get discharged at the positive electrode 


  form gas and float away
• how do ions usually get discharged at the negative electrode 


  fall to the bottom of the beaker and form layer of molten …
• what happends at the negative electrode O or R 


  reduction-gain of electrons
• what happens at the positive electrode O or R


  oxidation-loss of electrons
• why is reduction with carbon used 


  a metal is too reactive when we are trying to remove oxygen to make it a pure metal
• what is the disadvantage of reduction with carbon 


  it can only be used for metals that are less reactive than carbon
• whay is the advantage of reduction with carbon 


  cheaper and easier than electrolysis
• which electrode has to be continually replaced 


  positive
• why does the positive electrode have to be continually replaced 


  electrodes that are made of carbon, react with oxygen to produce carbon dioxide so need to be replaced
• what is the problem at first with aluminium in electrolysis 


  has to be extracted from the ore bauxite
• what does aluminium have to be mixed wiht in electrolysis 


  cryolite
• why does aluminium have to be mixed wiht cryolite in electrolysis 


  aluminium has very high melting point so is mixed with cryolite to lower this so to use less energy in electrolysis
• what adv does cryolite mean for aluminium electrolysis

  less expensive as less energy needed and better for the environment