Amount of energy required to purify copper using electrolysis?

The purification of copper by electrolysis involves an anode of impure copper and a cathode of pure copper. During the electrolysis, copper (II) ions leave the anode slab and plate onto the cathode slab.

The reaction at the anode is Cu(s) = Cu2+(aq) +2e-
The reaction at the cathode is Cu2+(aq) + 2e- = Cu(s)

Therefore, it would appear that these two reactions cancel out leaving an emf of zero.

I don't understand how you can calculate the amount of energy required to purify copper being that the emf is zero.

How much energy (in joules) is required to purify a given amount (i.e. 100g) of copper?

Is heat produced? Why or why not? If so, how much (heat)?

How much time would it take to deposit 115 g of copper from a copper sulfate solution using a 3.75 Amp current? Assuming optimum conditions and calculating theoretical time.
m = 115g Cu
F = Faraday's constant = 96,500 C mol ^-1
M = for Cu 63.55 g mol -1
Z = 2e-per atom for copper = 2
I = 3.75 A = 2.5C/s
t=x
Faraday's

The amount of product produced by electrolysis is limited by Faraday's law. Therefore, as I understand it, the amount of product produced depends on the amps rather than on the volts (although the minimum voltage for a given reaction plus overvoltage must be met).
For example, lets say you have a reaction that requires at

By the electrolysis of water, 11.2L of oxygen at STP was prepared.
a) What charge was required?
b) If a current of 0.5A was used, how long would it take?

Calculate the minimum energyrequired to produce molecular hydrogen from gas-phase water. Then compare this to the energy need to produce water electrochemically or photoelectrochemically. Finally, compare this to the energy needed to make this on a zirconia surface. Comment on why there are differences.

2. A 2kg copper pot contains 8 kg of water. Both are initially at 20°C. If heat is added so that the temperature is now 80°C, determine the amount of heat is put into each material; the copper and the water.
3. If we have 500ml of water, how many joules of energy will be required to change the temperature from 25°C to 95°

Electrolysis of a solution containing an unknown metal ion with a +3 charge deposited 0.159 g of the metal on the cathode over a period of 2.00 minutes at a constant current of 2.00 A. What is the molecular weight of the unknown?
A)
207 g/mol
B)
192 g/mol
C)
128 g/mol
D)
21.3 g/mol
E)
63.9 g/mol

Diffussion controlled electrolysis proceeds on (a) planar and (b) spherical electrode under the conditions: n = 1, C = 1 mM, A= 0.04 cm^2, D = 1.5x10^-5 cm^2/s.
Calculate the current (i) in both cases at t = 0.5, 1, 3, 10 sec.
How long can the electrolysis proceeed before the current at the spherical electrode exceeds that

Reduction through constant current electrolysis a) How much Cr3+ was reduced to Cr2+? b) A few seconds after the electrolysis was stopped, the potential of the cell came to rest at -0.524 volts. How much Cr3+ actually remains in the solution? c) What was the original Cr3+ concentration?