c3.4

Question 1

electrolysis

Answer 1

process where electric current is passed through an ionic compound to break it down

Question 2

electrolyte

Answer 2

a compound in its liquid state or in solution which contains mobile ions and conducts electricity

Question 3

electrodes

Answer 3

two electrodes made from metal or graphite which conduct electricity to electrolyte
negative electrode - cathode
positive - anode

Question 4

electrical supply

Answer 4

battery or power pack

Question 5

during electrolysis

Answer 5

positive ions(anions)gain electrons at cathode and become atoms
negative ions(cations) lose electrons at anode and become atoms
discharged - when ions become atoms

Question 6

why cant they be in solid state

Answer 6

Ionic compounds in the solid state cannot conduct electricity since they have no free ions that can move and carry the charge

Question 7

whats produced at the anode

Answer 7

oxygen produced unless it is halide (group 7)

Question 8

whats produced at cathode

Answer 8

metal if less reactive than hydrogen

Question 9

electroplating

Answer 9

uses non-inert electrodes
you want to coat cathode
anode is metal you want to coat with
electrolyte is solution containing ions of metal you want to coat with

Question 10

how is copper purified

Answer 10

both electrodes are copper
anode is impure copper
cathode is pure copper
electrolyte is copper(II) sulfate solution
cathode gains copper atoms, increases in mass
anode loses copper atoms and decreases in mass
impurities from anode fall off and collect underneath