Metal plating is done by passing current through a metal solution. For example,
ID: 841767 • Letter: M
Question
Metal plating is done by passing current through a metal solution. For example, an item can become gold plated by attaching the item to a power source and submerging it into a Au3+ solution. The item itself serves as the cathode, at which the Au3+ ions are reduced to Au(s). A piece of solid gold is used as the anode and is also connected to the power source, thus completing the circuit.
What mass of gold is produced when 5.00A of current are passed through a gold solution for 35.0min ?
Express your answer with the appropriate units.
mass of Au =
Explanation / Answer
5 A for 35 min is
5 Coulomb/s x 35 min x 60 sec/min = 10,500Coulombs
One Faraday is 96,500 Coulombs
10,500 Coulombs / 96,500 Coulombs / Faraday = 0.10880 Faraday
Au3+ + 3e- >> Au
For every 3 Faradays of electricity used up , one mole Au forms.
0.10880 Faraday x 1 mole Au/ 3 Faradays = 0.036266 mole Au
One mole Au is 196.967 g
196.967 g/mol x 0.0967 = 7.1432 g Au