 Solution

ID: past-exam-of-the-chemistry-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2021/paper-1/4/c/solution

Measure the reversible cell potential at several temperatures while maintaining standard-state thermodynamic activities and the same phases. From

Δ_{r} G^{\circ} = - n F E^{\circ}

and

Δ_{r} S^{\circ} = - (\partial Δ_{r} G^{\circ} / \partial T)_{p}

Δ_{r} S^{\circ} = n F (\frac{\partial E ^{\circ}}{\partial T})_{p} .

The sign of the slope gives the sign of the standard reaction entropy. Measuring a loaded cell voltage without correcting polarization would not give this reversible thermodynamic derivative.

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