Elemental calcium is produced by the electrolysis of molen CaCl2.

What mass of calcium can be produced by this process if a current of 8500 A is applied for 39 h? Assume that the electrolytic cell is 65% efficient. I found the mass to equal 1.6 x10^5g Ca, and that is correct.

It’s part B that I’m struggling with. What is the total energy requirement for this electrolysis if the applied emf is + 5.20 V?

I keep getting 1100 kWh, but it’s saying that it’s incorrect.

I did (1.6 x 10^5g)(1 mol Ca/40.078 g Ca)(2 mol e-/1 mol Ca)(96,485 C/1 mol e-)

(770, 377, 763.4 V)(5.20 V)(1 J/1C-V)(1 kWh)(3.6 x 10^6 J)=1100 kWh

What am I doing wrong?

1 answer

This was for online homework that was due tonight, and the answer is .43 kWh, but I'd still like to know how to get this answer. Thank you!!