I ran into the same issue, to me determining the KWH is simple, multiply current+Volts* hrs used and you will get KWH. But for some reason the answer that they have given is the energy requirement for a single reaction so here is how you figure it. kwh=(nfE)/(3.6e6 * efficiency),
so 2*96500*5.2/(3.6e6*.65)=.43 kwh. This is the energy requirement for a single reaction. While I don't agree with the answer as the question obviously states that it is looking for the total energy requirement of the reaction in part A, it is the answer that they are looking for.
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?
The answer is .43 kWh, but I'd like to know how to get this answer. Thank you!!
1 answer
1 answer