Question

A Zn|Zn²⁺ || Au³⁺|Au galvanic cell is constructed in which the standard cell voltage is 2.18 V. Calculate the free energy change at 25°C when 0.767 g of Au plates out, if all concentrations remain at their standard value of 1 M throughout the process. What is the maximum amount of work that could be done by the cell on its surroundings during this experiment?

ΔG° =  J

Maximum work =  J

Answer 1

Given Ecell=2.18 V, weight of gold plates=0.767 g, moles of Au plates n=weight/molecular weight=0.767 g/196.96 g/mol=0.00389 mol Au plates and Faraday constant F=96485 C/mol.

Delta G=-nFEcell=-(0.00389 mol)*(96485 C/mol)*(2.81 V)

Delta G=-1054.667 C.V

1 Columb= Joule/Volt=> Joule=Columb.Volt

Delta G=-1054.667 J.

Gibbs energy is the maximum useful work that a system can do on its surroundings when the process occurring within the system is reversible at constant temperature and pressure.

So maximum work=-1054.667 J.