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Ch.19 - Electrochemistry
Chapter 19, Problem 72

Calculate ΔG°rxn and E°cell for a redox reaction with n = 3 that has an equilibrium constant of K = 0.050 (at 25 °C).

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1
Identify the relationship between the equilibrium constant (K) and the standard Gibbs free energy change (ΔG°) using the equation: ΔG° = -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° = - (8.314 J/mol·K) * (298 K) * ln(0.050).
Calculate the natural logarithm of the equilibrium constant, ln(0.050).
Use the calculated value of ln(0.050) to find ΔG° by completing the multiplication and division in the equation.
To find the standard cell potential (E°cell), use the relationship between ΔG° and E°cell: ΔG° = -nFE°cell, where n is the number of moles of electrons transferred (3 in this case) and F is Faraday's constant (96485 C/mol). Rearrange the equation to solve for E°cell: E°cell = -ΔG° / (nF).