non standard cell potential

Question

Calculate the non-standard cell potential (in V) for the following reaction at 839.55 ℃ with the following concentrations: [] =  M; [] =  M

(aq) + Mg(s) --> Cu(s) + (aq)

Answer 1

Nernst Equation: E_cell = Eº - RT/nF ln Q

R = 8.314 J/mol-K

T = temperature in K =839.55 + 273.15 = 1112.7K

n = # of moles of electrons transferred = 2

F = Faraday constant = 96485 C/mol e-

Q = reaction quotient expression (see below)

Q = [Mg²⁺] / [Cu²⁺] = 9.00x10^-2 M / 1.60x10^-5 M

Q = 5.63x10³

From a table of standard reduction potentials, we find the following values:

Cu²⁺ + 2e- ==> Cu(s) Eº = +0.34 V

Mg²⁺ + 2e- ==> Mg(s) Eº = -2.38 V

Eº_cell = 0.34 - (-2.38) = +2.72 V

E_cell = 2.72 - (8.314)(1112.7) / (2)(96485) ln 5.63x10³

E_cell = 2.72 - (0.0479)(8.64) = 2.72 - 0.41

E_cell = 2.31 V

(Please check my math)