How to find n in ΔG°= -nFE°

[Annie Chantasirivisal_4G]

6L.1 Calculate the standard reaction Gibbs free energy for the following cell reactions:

(a) 2 Ce4+(aq) + 3 I−(aq) →2 Ce3+(aq) + I3−(aq), E cell°=+1.08V

(b) 6 Fe3+(aq) + 2 Cr3+(aq) + 7 H2O(l) → 6 Fe2+(aq) + Cr2O72−(aq) + 14 H+(aq), E cell°=−1.29V

I'm still having trouble finding n when given a redox reaction in order to use the formula ΔG°= -nFE°, can someone please guide me through this thought process? Perhaps by using one of the reactions in 6L.1?

[Jasmine Kim 1L]

n is the amount of electrons being transferred, so you just need to find that, which we've been doing with half-reactions. You can split up the redox reaction into 2 half-reactions.
In , you can tell that there are 2 electrons being added. In , 2 electrons are being taken away, which you can tell because the 3 negatively charged atoms should've had a charge of 3- when they bonded, but they have a charge of 1-.
So n = 2

[Norman Dis4C]

In this question, E is given and F is a constant. The only thing you need to find is n, which is the electron transferred. By breaking down the reaction into two half-reaction, you will know the number of electrons transferred by the change in its charges.