In: Chemistry
Consider the cell described below at 261 K:
Fe | Fe2+ (0.903 M) || Cd2+ (0.991 M) | Cd
Given EoCd2+→Cd = -0.403 V, EoFe2+→Fe = -0.441 V. Calculate the cell potential after the reaction has operated long enough for the Fe2+ to have changed by 0.373 mol/L
Fe --> Fe+2 + 2e- ... Eo = - 0.0.441 volts
Cd+2 + 2 e- --> Cu ... Eo = - 0.403 volts
cell potential ... Eo = -0.403 (-0.441) = 0.038V
Fe
+ Cd+2 --> Fe+2 + Cd
Initial
0.991 0.903
Change
0.373
0.373
Fina
0.618
1.276
-------
nernst Equation
E = Eo - (0.0592/n) log Q
E = 0.038 volts - (0.0592/2) log [Fe+2] /
[Cd+2]
E = 0.038 volts - (0.0296) log [1.276] / [0.618]
E = 0.038 volts - (0.0296) log 2.064
E = 0.038 volts - (0.0296) (0.314)
E = 0.038 volts - 0.00929
your answer is: E = 0.0287 volts