Consider the electrochemical cell shown using line notation and the standard red

Question

Consider the electrochemical cell shown using line notation and the standard reduction potentials in the table below: Pt| Fe^2 (0.30M), Fe^3+ (0.20M)||MnO_4^-1 (0.30M), H^+ (0.10M), Mn^2+ (0.20M)|Pt Which of the following balanced chemical equations corresponds to this line notation? The 298 K value of E degree_cell is ______and the change in free energy for this cell is best represented by which of the following expressions? E degree_cell = 0.739 V and deltaG degree = 0.739F E degree_cell = 0.739 V and delta G degree = 1.48F E degree_cell = 0.739 V and delta G degree = -3.70F E degree_cell = 2.28 V and delta G degree = +0.739F E degree_cell = 2.28 V and delta G degree = +3.70F Now use the concentrations given in the line notation to find the 298 K value of E_cell = for this electrochemical cell? E degree_cell = 2.27 V E degree_cell = 2.20 V E degree_cell = 0.739 E degree_cell = 0.731 V E degree_cell = 0.657 V What is the value of the equilibrium constant (K) for this cell at 298K? K = e^356 K = e^-143 K = e^143 K = e^71.3 K = e^28.7

Explanation / Answer

Q24

the Pt will not be SHOWN! since those are only indications of Pt

so:

Fe+2 = Fe+3

MnO4- = H+Mn+2

this is not balanced

so

ignore Fe+3 in reactants... that is, b and c

d is not balanced

therefore, choose E

Q25

Etotal:

Ered - Eox

Fe is being oxidized, so we need 0.771

MnO4- reduces so we need 1.51

Ecell = 1.51-0.771 = 0.739 V

so

dG = nF*Ecell = -5*F*0.739

dG = -3.695F

choose C

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