c6
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what is electrolysis
is the process that uses electricity to break down ionic compounds into elements
what is electrolyte
liquid or solution which contains an ionic compound
what are electrodes usually made of
inert substances that does not react with products
what is the positive electrode called
anode
what is the negative electrode called
cathode
where do negatively charged ions go in electrolysis
to the anode
where do positively charged ions go in electrolysis
to the cathode
what happens when the ions reach the electrodes
they lose their charge and become atoms or molecules
what happens when you electrolyse an ionic compound in an aqueous solution
the positively charged ions will form hydrogen or metal depending on the reactivity
practice writing half equations
….
what happens if two elements can be formed at the cathode
the less reactive element will be formed
remember the half equations for hydrogen and oxygen in electrolysis
where do you get aluminium from
ore bauxite
why must aluminium be extracted by electrolysis
as it is more reactive than carbon
why is aluminium oxide mixed with cryolite
to lower its melting point from 2000 degrees to then be electrolysed at 850 degrees
why do the carbon anodes have to be replaced regularly in the extraction of aluminium
the oxygen that forms at the hot carbon anodes reacts to produce carbon dioxide which then gradually burns the anode away
what is brine
solution of sodium chloride in water
what happens if the solution being electrolysed contain halide ions
then the halogen will be produced
why are some ionic compounds melted or dissolved in water
soluble - dissolved in water insoluble - melted
what happens at the anode and cathode
anode - oxidised cathode - reduced