Cell Potential and Gibbs Free Energy share connections to spontaneity
Concept #1: Gibbs Free Energy ties into the capacity of an electrochemical cell to do electrical work.
Example #1: Calculate the maximum electrical work that can be produced by this cell.
3 Co2+ (aq) + 2 Cr (s) →. 2 Cr3+ (aq) + 3 Co (s)
Given the following reduction potentials:
Cr3+ + 3 e– → Cr E°red = – 0.74 Volts
Co2+ (aq) + 2 e– → Co E°red = – 0.28 Volts
Concept #2: Faraday's Constant serves as the bridge betweeen charge and moles of electrons transferred.
Example #2: How many electrons were transferred between an anode and cathode that produced 482.425 kJ of energy?
Practice: What is the gibbs free energy change for the given reaction at 25ºC?
Au3+ (aq) + 3 Li (s) →. Au (s) + 3 Li+ (aq)
Given the following reduction potentials:
Au3+(aq) + 3 e– →. Au (s) E°red = + 1.50 Volts
Li+ (aq) + e– →. Li (s) E°red = – 3.04 Volts
Practice: The reduction of chlorate is given by the equation:
ClO3– (aq) + 6 H3O+ (aq) → Cl – (aq) + 9 H2O (l)
If the standard cell potential is given as 1.373 V, how many electrons are transferred under standard conditions?
