In an electrolysis cell how many seconds are required to plate out 2.50 g of copper metal from a solution of CuSO4 that is electrolyzed using a current of 3.00 amps?

Question

In an electrolysis cell how many seconds are required to plate out 2.50 g of copper metal from a solution of CuSO4 that is electrolyzed using a current of 3.00 amps?

Answer 1

Cu²⁺(aq) + 2e- ==> Cu(s)

Each mole of Cu²⁺ requires 2 moles of electrons, so we can find moles of Cu²⁺ and then moles of electrons.

2.50 g Cu²⁺ x 1 mol Cu/63.5 g = 0.0397 moles Cu

moles of electrons = 0.0397 mol Cu x 2 mol e- / mol Cu = 0.0794 moles e-

Each mole of electrons = 96,500 coulombs

Coulombs = 0.0794 mol e- x 96,500 C/mol e- = 7662 C

1 amp = 1 C/sec

3 amps = 3 C/sec

7662 C x 1 sec/3C = 2554 seconds