For the reaction 2 Al(s)+ 3 Co²⁺(aq)→ 2 Al³⁺(aq)+ 3 Co(s),ΔG° is -799 kJ.What is E° for a standard cell based on this reaction?

Question

Quizplus · Accepted Answer

The standard Gibbs free energy change (ΔG°) and the standard electromotive force (E°) for a cell are related by the equation ΔG° = -nFE°, where n is the number of moles of electrons transferred in the reaction, F is the Faraday constant (96485 C/mol), and E° is the standard electromotive force of the cell in volts. For the given reaction, 6 moles of electrons are transferred (2 for each Al, as it goes from 0 to +3 oxidation state). Rearranging the equation to solve for E° gives E° = -ΔG°/(nF). Substituting the given ΔG° (-799,000 J or -799 kJ) and the values for n and F gives E° = 799,000 J/(6 mol * 96485 C/mol) = 1.38 V.

For the Reaction 2 Al(s)+ 3 Co2+(aq)→ 2 Al3+(aq)+ 3

For the Reaction 2 Al(s)+ 3 Co²⁺(aq)→ 2 Al³⁺(aq)+ 3