Delta G=-nFE


Moderators: Chem_Mod, Chem_Admin

John Huang 1G
Posts: 46
Joined: Thu Jul 13, 2017 3:00 am
Been upvoted: 1 time

Delta G=-nFE

Postby John Huang 1G » Thu Feb 15, 2018 10:14 pm

A lot of the problems do not have moles given, so when we are using DeltaG=-nFE, what value would we use for n?

Dylan Mai 1D
Posts: 70
Joined: Sat Jul 22, 2017 3:00 am

Re: Delta G=-nFE

Postby Dylan Mai 1D » Thu Feb 15, 2018 10:27 pm

do you have an example of one of the problems that does this?

Rachel Formaker 1E
Posts: 86
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 2 times

Re: Delta G=-nFE

Postby Rachel Formaker 1E » Thu Feb 15, 2018 11:36 pm

Moles in the equation ΔG=-nFE is for moles of electrons, so even if the moles of a substance are not explicitly given, you should be able to figure out the moles of electrons through the redox half-reactions.

Julie Steklof 1A
Posts: 50
Joined: Thu Jul 13, 2017 3:00 am

Re: Delta G=-nFE

Postby Julie Steklof 1A » Thu Feb 15, 2018 11:52 pm

After writing balanced half reactions, you will be able to see the moles of electrons involved in the redox reaction. This is the number you use for n.

Ivy Lu 1C
Posts: 54
Joined: Thu Jul 27, 2017 3:00 am

Re: Delta G=-nFE

Postby Ivy Lu 1C » Sat Feb 17, 2018 1:20 pm

The n in the equation is the moles of electrons transferred. To find the electrons transferred, you'll have to write the two half-reactions and balance them.

Jeremiah Samaniego 2C
Posts: 33
Joined: Fri Sep 29, 2017 7:05 am

Re: Delta G=-nFE

Postby Jeremiah Samaniego 2C » Sat Feb 17, 2018 8:38 pm

Ivy Lu 1C wrote:The n in the equation is the moles of electrons transferred. To find the electrons transferred, you'll have to write the two half-reactions and balance them.


A good example of this is homework problem 14.9.a):

Given the overall equation 2 Ce4+ (aq) + 3 I- (aq) --> 2 Ce3+ (aq) + I3- (aq), the half reactions would be:
2 Ce4+ (aq) + 2 e- --> 2 Ce3+ (aq) and 3 I- (aq) --> I3- (aq) + 2 e-.

Since 2 moles of electrons are being transferred in the overall reaction, you would plug in 2 for n in the equation Delta G = -nFE


Return to “Work, Gibbs Free Energy, Cell (Redox) Potentials”

Who is online

Users browsing this forum: No registered users and 0 guests