Consider a fuel cell that uses the reaction of ethanol with oxygen to produce electricity,
CH3CH2OH(l) + 3O2(g) → 2CO2(g)+ 3H2O(l)
Determine the E°cell for this cell at 25°.
E°cell = v
We’re asked to calculate the cell potential (E°cell) of a fuel cell. The cell potential of an electrochemical cell is related to Gibb's free energy of the reaction by the following equation:
∆G° = Gibb’s Free Energy
n = number of electrons transferred
F = Faraday’s constant = 96485 C/(mol e-)
E°cell =standard cell potential
We will solve the problem in the following steps:
1. Calculate ΔG˚rxn (since it is not given)
2. Determine the number of electrons involved in the reaction by balancing the redox reaction
3. Calculate E˚cell using the equation above.