# Electroplating Question

1. Aug 21, 2011

### dav1d

1. The problem statement, all variables and given/known data

Exactly 21.6 g of silver is deposited during an
electroplating experiment. The same amount of
electricity is passed through 1.00 L of a 1.00 mol/L
CuSO4(aq) solution. What mass of copper is
deposited?
Relative atomic masses:
Ag 107.87; Cu 63.55

2. Relevant equations

3. The attempt at a solution

I really have no idea how to do this.

2. Aug 22, 2011

### Staff: Mentor

Do you know Faraday's law of electrolysis?

3. Aug 22, 2011

### dav1d

No, never heard of it. Can you link me to it?

4. Aug 22, 2011

### Staff: Mentor

5. Aug 22, 2011

### dav1d

m=(Q/F)(M/z)

m is the mass of the substance liberated at an electrode in grams
Q is the total electric charge passed through the substance
F = 96,485 C mol−1 is the Faraday constant
M is the molar mass of the substance
z is the valency number of ions of the substance (electrons transferred per ion).

so

Q:how do i find the total charge? Only given The same amount of
electricity is passed

F=const
M: 63.55
z=1 or 2???

6. Aug 22, 2011

### Staff: Mentor

What reactions are taking place during electrodeposition of both metals? What is z?

Come on, show some effort, so far you are just asking for help on each step. We can help, we can't spoonfeed you.

7. Aug 22, 2011

### dav1d

I just don't really understand.

Redox is happening during the electrodeposition? Z is the valence number but copper is multivalent so it can be 1 or 2?

wait

Can't you just rearrange the equation for Q, plug in the 21.6 grams from aluminum and then find the Q?
Then redo the equation with Q solved for and then plugin everything else, F=const, M=unkown, and then Z still is 1 or 2?

8. Aug 22, 2011

### Staff: Mentor

No idea where did you got aluminum from. But yes, you have to find the charge from known amount of reduced silver.

You are specifically told to use CuSO4, what is the valence of the copper in this compound?

9. Aug 22, 2011

### dav1d

Exactly 21.6 g of silver is deposited during an
electroplating experiment. The same amount of
electricity is passed through 1.00 L of a 1.00 mol/L
CuSO4(aq) solution.

It should be 2+ for the Cu correct?

10. Aug 22, 2011

Yes.