## How to calculate for n

$\Delta G^{\circ} = -nFE_{cell}^{\circ}$

Bryce Ramirez 1J
Posts: 120
Joined: Sat Aug 24, 2019 12:16 am

### How to calculate for n

When calculating for Gibbs free energy, you use the equation Delta G = -n*F*Ecell, but how do you determine the n? It says to use Equation 1a in the textbook, but I don't know what that equation is. Also, do we have to set up an half reactions for solving for this or will we just be able to plug in the numbers to an equation and solve for the n.

Brooke Yasuda 2J
Posts: 102
Joined: Sat Jul 20, 2019 12:17 am

### Re: How to calculate for n

The n value that is referenced in this equation is the number of electrons that is transferred in the redox reaction. So yes, you should write and balance the half reactions and then plug in the value of n into the equation to find the Gibbs Free Energy.

Verity Lai 2K
Posts: 100
Joined: Sat Aug 24, 2019 12:18 am

### Re: How to calculate for n

n is the moles of electrons being transferred during a redox reaction. You find it by balancing the redox reaction and I'm not sure about if you can find n by plugging in numbers and solving for n. I think the best method is using the redox reaction.

Justin Seok 2A
Posts: 104
Joined: Sat Aug 24, 2019 12:15 am

### Re: How to calculate for n

By looking at the redox equations, you can find n by looking at the amount of electrons transferred, like Cu ---> Cu2+ + 2e-. In this case n=2 since 2 electrons are being transferred.

Pegah Nasseri 1K
Posts: 100
Joined: Wed Feb 27, 2019 12:15 am

### Re: How to calculate for n

Like others have mentioned, you would find n by balancing the oxidation and reduction half reactions and adding them up. For example, if you have these as your half reactions:
Fe3+(aq) + e- -> Fe2+(aq)
Zn(s) -> Zn2+(aq) + 2e-
You would multiply the top reaction by 2 so you can have 2 electrons reacting in each reaction, allowing you to add up the half reactions. Then when finding delta G, you would use n=2.

Charysa Santos 4G
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Joined: Wed Sep 18, 2019 12:21 am

### Re: How to calculate for n

You must find n by balancing the half reactions and seeing how many electrons are transferred (which is your n value)

Leonardo Le Merle 1D
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Joined: Wed Feb 27, 2019 12:16 am

### Re: How to calculate for n

It should be noted that some balancing is necessary to identify n, which is the balanced amount of electrons between the two redox reactions. For instance, with an oxidation that loses 2 electrons and a reduction that gains 3, n would be 6. I would

Minh Ngo 4G
Posts: 137
Joined: Thu Jul 25, 2019 12:17 am

### Re: How to calculate for n

n is the number of electron that are being transferred