Free-energy change, ΔG?, is related to cell potential, E?, by the equation ΔG?=−nFE? where n is the number of moles of electrons transferred and F=96,500C/(mol e−) is the Faraday constant

Free-energy change, ΔG?, is related to cell potential, E?, by the equation

ΔG?=−nFE?

where n is the number of moles of electrons transferred and F=96,500C/(mol e−) is the Faraday constant. When E? is measured in volts, ΔG? must be in joules since 1 J=1 C⋅V.

1. Calculate the standard free-energy change at 25 ?C for the following reaction:

Mg(s)+Fe2+(aq)→Mg2+(aq)+Fe(s)

Express your answer to three significant figures and include the appropriate units.

2. Calculate the standard cell potential at 25 ?C for the reaction

X(s)+2Y+(aq)→X2+(aq)+2Y(s)

where ΔH? = -675 kJ and ΔS? = -357 J/K .

Express your answer to three significant figures and include the appropriate units.