A galvanic cell is constructed from the following half-cells at 298 K: • Fe³⁺(aq) +…
CHEMISTRY · Multi-part · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry
Problem
A galvanic cell is constructed from the following half-cells at 298 K:
• Fe³⁺(aq) + e⁻ ⇌ Fe²⁺(aq), E° = +0.771 V
• Cu²⁺(aq) + 2 e⁻ ⇌ Cu(s), E° = +0.337 V
The initial ion concentrations are [Fe³⁺] = 0.100 M, [Fe²⁺] = 1.00 M, and [Cu²⁺] = 0.0100 M. The copper electrode is a pure Cu(s) strip; the iron half-cell contains only the aqueous ions. The temperature is maintained at 298 K. (Faraday constant F = 96 485 C mol⁻¹; R = 8.314 J mol⁻¹ K⁻¹.)
(1) Write the balanced overall cell reaction in the direction that is spontaneous under standard-state conditions, and specify the number of electrons transferred, n.
(2) Using the standard electrode potentials, calculate ΔG° (in kJ) for the balanced overall reaction.
(3) For the non-standard ion concentrations given, calculate the Gibbs free energy change, ΔG, for the cell reaction at 298 K.
(4) Determine the instantaneous cell potential, E, under the stated conditions.
(5) Explain whether the cell, as configured, will spontaneously operate to produce electrical work, and justify your conclusion based on your calculated values of ΔG and E.