The standard free energy change for a reaction can be calculated using the equation Δ∘′=−Δ∘′

where
is the number of electrons transferred,
is Faraday's constant, 96.5 kJ·mol−1·V−1, and Δ∘′
is the difference in reduction potential.

For each of the given reactions, determine the number of electrons transferred ()
and calculate standard free energy (Δ∘′)
.

Consider the half-reactions and overall reaction for reaction 1.

half-reactions:fumarate2−+2H+CoQH2↽ −−⇀succinate2−↽−−⇀CoQ+2H+
half-reactions:
fumarate
2
−
+2
H
+
↽
−
−
⇀
succinate
2
−
CoQH
2
↽
−
−
⇀
CoQ+2
H
+

overall reaction:fumarate2−+CoQH2↽−−⇀succin ate2−+CoQΔ∘′=−0.009 V