electrolysis Flashcards
main parts of electrolysis
breaker filled with liquid or molten where the soluable electrolyte freely moves
two conducting electrodes- anode and cathode- one pos one neg, made up of unreactive substances to not react w electrolyte
where to the ions move to
pos ions, usually metals move to the neg cathode whilst the neg ions move to the anpde
what happens at the anode
ions loose their charge
gases given off
metals disposed of
ways to dissolve ionic compounds
if theres a v high melting point it takes a lot of energy to melt it so it needs to be dissolved in a molten liquid
some are easier and jsut need a water
whats different about electrolysis in water
water unlike molten also has its own ions so the product at each electrons are essentially competing to be formed
only metals less reactive than hydrogen (h+) can be formed at the cathode
at the anode it goes halide (group seven ion) > hydroxide ion > any other negative
gaining electrons is..
reduction
losing electrons is…
oxidisation
half exaqutions of PbBr2 in a molten compound
pb (2+) + 2e = pb
2br (2-) - 2e = br
uses of aliminium
pans
foil
cans
main steps to electrolyse alO
purify AlO from the bauxite ore
mix the purified solid with cryolite to lower the boiling point to use less energy
melt to form a molten mixture
what to mix with AlO to lower melting point
cryolite
overall reaction of the electrolysis of AlO
2Al2O3 = 4Al + 3O2
equation for aluminium at cathode
Al (3+) + 3E (-3) = Al
equation for oxygen at the anode
2O (-2) - 2E = O2
why do carbon anodes need to be replaced
because the oxygen reacts with it to form co2 which means it graduallay combusts away
