Calculate delta G rxn for a redox reaction with n = 2 that has an equilibrium constant of K = 4.4×10−2.
To calculate the standard Gibbs free energy change (ΔG°) for a redox reaction, you need to use the formula:
ΔG° = -nFΔE°
where:
- ΔG° is the standard Gibbs free energy change (in Joules),
- n is the number of electrons transferred in the reaction,
- F is the Faraday constant (approximately 96,485 C/mol), and
- ΔE° is the standard cell potential (in Volts).
Since n = 2 in this case, we can use this value in the equation.
To find ΔE°, we need the expression for the standard cell potential (E°) in terms of the equilibrium constant (K):
ΔE° = (0.0592 V/n) x log(K)
where:
- ΔE° is the standard cell potential (in Volts),
- n is the number of electrons transferred in the reaction (which is 2 in this case),
- K is the equilibrium constant, and
- log denotes the logarithm to the base 10.
Given that K = 4.4×10^(-2), we can substitute this value into the equation to calculate ΔE°:
ΔE° = (0.0592 V/2) x log(4.4×10^(-2))
Now, calculate ΔE° using this expression.