## negative sign

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

Sophia Dinh 1D
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### negative sign

why is there a negative sign in front of n in the standard Gibbs energy equation?

Jessa Maheras 4F
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### Re: negative sign

I believe that there is a negative sign due to the loss of energy.

Indy Bui 1l
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### Re: negative sign

I believe it has to do with the relationship between E and delta G. When E is positive, delta G should be negative meaning it is spontaneous.

Wilson 2E
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Joined: Sat Aug 17, 2019 12:18 am

### Re: negative sign

Energy = -work/Charge;
Rearrange this to get work = -E*Charge
From the Farraday's constant, Charge = n*F
Therefore work = -n*F*E
At constant temp and pressure, work max = deltaG
Therefore deltaG = -n*F*E

Philip
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### Re: negative sign

I think it's to show that energy is release or loss

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### Re: negative sign

delta G*= -nFE
w(max)=-nFE
The system is doing work, so energy leaves the system resulting in -w.

Jared_Yuge
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### Re: negative sign

When E is positive it is spontaneous, so delta G needs to be negative

Frankie Mele 3J
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### Re: negative sign

Favorable redox reactions have positive voltage differences which results in E being a positive value and deltaG therefore being negative.

Lesly Lopez 3A
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### Re: negative sign

The negative sign is important because it is telling you that the reaction has released or lost energy. The relationship between E and $\Delta$
G is that when E is positive, $\Delta$G should be negative meaning the reaction is spontaneous.

Samantha Lee 1A
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### Re: negative sign

Yes! There is a negative sign in front of the n. The equation is $\Delta G^{\circ } = -nFE^{^{\circ}}$

When the reaction is spontaneous, the $\Delta G^{\circ }$ is negative and $E^{\circ }$ is positive. In order for that to occur, there must be a negative sign in the equation.

Kimiya Aframian IB
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### Re: negative sign

Sophia Dinh 1D wrote:why is there a negative sign in front of n in the standard Gibbs energy equation?

Hi! I think the negative sign in front of the n (mole value) is because it keeps the relationship between E, delta G, and spontaneity consistent. By this I mean that we need the E value to be positive when delta G is negative. Hope this helps!

Dominic Benna 2E
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### Re: negative sign

A spontaneous reaction has a positive delta E, yet a negative delta G. So, in order to relate the two to each other, the negative sign is added.

Edison Tham 3D
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### Re: negative sign

The system is doing work and based on the fact that ∆G = maximum work, this would mean that there would be a negative sign.