2016 Final Question 4a

[Coco Hailey 2E]

Overall rxn is
2Fe + 2H20 + 02 --> 2Fe(OH)2 Estandard = .840
Droplet 1: [O2] = .00117, E= 0.796V after 100s

What is the reaction quotient for droplet 1?

Answer:

n = 4
plug into E=Estandard -RT/nFlnQ
Q = 942.23

I understand the plugging part, but I have two questions. How are the number of moles found? And could the equation E = Estandard - 0.0592/n log Q also be used?

[Serena Patel 2H]

To answer your first question, I'm not 100% sure but I think its from the electrons in the balanced reaction. If you add up the charges on the reactants side of the equation, you get -4 and for the products side, the charge is 0. I'm assuming the n=4 refers to the 4 electrons that would be "added" to the products side to make the charges on both the sides same.

[Nikhita_Jaaswal_2H]

Yes, the n refers to the number of electrons that are transferred during the redox reaction.