Copper is plated onto the cathode of an electrolytic cell containing CuCl2 (aq). How long does it take to plate 145 mg of copper with a current of 3.6 A

122 seconds

Explanation:

Cu{2+} + 2 e{-} → Cu

the stoichiometric relationships between miles of the electron and the moles of

Cu is 2 mol e - : 1 mol Cu

you are given copper mass (145 mg) and current (3.6 A).

Remember that,

1A = 1C/s, 1g = 1000 mg and molar mass of Cu = 63.55 g/mol

145 mg = 0.145 g

= (0.145 g Cu) / (63.55 g Cu/mol) x (2 mol e{-} / 1 mol Cu) x (9.64853399 x 10^4 C/mol e{-}) / (3.6 A)

= 0.00228 x 2 x 26777.7

= 122 seconds