Lots of Chemistry help about electricity...?

Question

I have 188 problems to do and I can only do about 160... the rest throw me off a bit. Please help! Thanks.

A voltaic cell is constructed that uses the following reaction and operates at 298 K.

Zn(s) + Ni2+(aq) Zn2+(aq) + Ni(s)

(b) What is the emf of this cell when [Ni2+] = 2.26 M and [Zn2+] = 0.116 M?
Answer in Volts...
(c) What is the emf of the cell when [Ni2+] = 0.239 M and [Zn2+] = 0.829 M?
Answer in Volts....
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(a) A Cr3+(aq) solution is electrolyzed using a current of 8.25 A. What mass of Cr(s) is plated out after 2.20 days?
Answer in Grams...
(b) What amperage is required to plate out 0.255 mol Cr from a Cr3+ solution in a period of 8.00 hr?
Answer in A...
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Answer 1

The related standard reduction potentials are:
Zn2+(aq) + 2e− → Zn(s), Eo = −0.76 V
Ni2+(aq) + 2e− → Ni(s), Eo = −0.25 V

Use the second one to subtract the first one:
Zn(s) + Ni(2+)(aq) → Zn(2+)(aq) + Ni(s), Eo = 0.51 V

Using Nernst equation:
E = E° + (0.0591/n)*log([Ni(2+)]/ [Zn(2+)])
= 0.51+(0.0591/2)*log(2.26/0.116)
= 0.55V
You now solve for condition (c)

(a) Notice that 1A = 1C/sec, and the charge of 1 mole of electron is 6.022e23*1.6e-19 = 96485 C = 1 Faraday.
Therefore to plate out 1 mole of Cr needs to supply 3 Faradays electricity.
The mass of Cr plated out is:
{(8.25C/s)*(2.20*24*3600s)/(3*96485C/mol)}*52.0g/mol = 282 grams.
You now solve for condition (b)