Question

1302 - 4.3 - Gold Electroplating - Copy © 20 of 20 m Review Constants 1 Periodic Tabl Part A 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 Au'+ 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 22.5 A of current are passed through a gold solution for 10.0 min ? Express your answer with the appropriate units. P Å An O 2 ? mass of Au = mass of Au = Value Units Submit Request Answer

Answer 1

Electrolysis equation is:
Au3+   +   3e-    ------> Au

1 mol of Au requires 3 mol of electron
1 mol of electron = 96485 C
So,1 mol of Au requires 289455 C

let us calculate the charge passed:
t = 10.0 min = 10.0*60 s = 6*10^2 s

time, t = 6*10^2s

Q = I*t
= 22.5A * 6*10^2s
= 1.35*10^4 C

mol of Au plated = 1.35*10^4/289455 = 4.664*10^-2 mol
Molar mass of Au = 1.97*10^2 g/mol

mass of Au = number of mol * molar mass
= 4.664*10^-2 * 1.97*10^2
= 9.188 g
Answer: 9.19 g