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Ch.19 - Electrochemistry
Chapter 19, Problem 71

Calculate ΔG°_rxn and E°_cell for a redox reaction with n = 2 that has an equilibrium constant of K = 25 (at 25 °C).

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1
Identify the relationship between the equilibrium constant (K) and the standard Gibbs free energy change (ΔG°_rxn) using the equation: ΔG°_rxn = -RT ln(K), where R is the universal gas constant (8.314 J/mol·K) and T is the temperature in Kelvin (298 K for 25 °C).
Substitute the given values into the equation: ΔG°_rxn = -(8.314 J/mol·K)(298 K) ln(25).
Calculate the natural logarithm of the equilibrium constant, ln(25).
Use the calculated value of ln(25) to find ΔG°_rxn by completing the multiplication and division in the equation.
Relate ΔG°_rxn to the standard cell potential (E°_cell) using the equation: ΔG°_rxn = -nFE°_cell, where n is the number of moles of electrons transferred (n = 2) and F is Faraday's constant (96485 C/mol). Solve for E°_cell by rearranging the equation: E°_cell = -ΔG°_rxn / (nF).