Question

Consider the reaction Mg(s)+Fe2+(aq)→Mg2+(aq)+Fe(s) at 61 ∘C , where [Fe2+]= 2.80 M and [Mg2+]= 0.210 M .

A. What is the value for the reaction quotient, Q, for the cell?

B. What is the value for the temperature, T, in kelvins? What is the value for n?

C. Calculate the cell potential.

Answer 1

Mg(s)+Fe2+(aq) --------------> Mg2+(aq)+Fe(s)

A)

recation quotient Q = [Mg+2] / [Fe+2]

                               = 0.210 / 2.80

  recation quotient Q = 0.075

B)

temperature T = 61 oC

                        = 61 + 273

temperature T = 334 K

n = 2

C)

Eocell = - 0.44 - (- 2.38) = 1.94 V

Ecell = Eo - 8.314 x 334 / 2 x 96485 ln 0.075

        = 1.94 - (- 0.037)

        = 1.98 V