C3.4.3 - Electroplating

Question 1

What is electroplating?

Answer 1

A type of electrolysis that uses non-inert electrodes which change during electrolysis

Question 2

What do you need for electroplating?

Answer 2

• The cathode which is the object you want to coat
• The anode which is a piece of metal you want to coat the object with
• The electrolyte is a solution containing ions of the coating metal

Question 3

What happens during electroplating with silver?

Answer 3

• silver atoms lose electrons at the anode:
  Ag(s) -> Ag+(aq) + e-
• silver atoms gain electrons at the cathode:
  Ag(aq) + e- -> Ag(s)

Question 4

How is copper purified?

Answer 4

For this the anode is impure copper, the cathode is pure copper and the electrolyte is copper(II) sulfate solution. During electrolysis, the cathode gains copper atoms and increases in mass, while the anode lose copper atoms and decreases in mass. Impurities from the anode fall off and collect underneath it

Question 5

How does electroplating work?

Answer 5

Metal ions from the electrolyte are discharged on the surface of the object (the cathode). These ions are replaced by metal ions leaving the surface of the anode. Overall, metal leaves the anode and is deposited on the object. This process continues until the anode is used up