## negative sign

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

Sophia Dinh 1D
Posts: 100
Joined: Thu Jul 25, 2019 12:15 am

### negative sign

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

Jessa Maheras 4F
Posts: 121
Joined: Fri Aug 02, 2019 12:16 am

### Re: negative sign

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

Indy Bui 1l
Posts: 99
Joined: Sat Sep 07, 2019 12:19 am

### 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
Posts: 100
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
Posts: 100
Joined: Sat Sep 07, 2019 12:16 am

### Re: negative sign

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

Posts: 45
Joined: Sat Aug 17, 2019 12:16 am

### Re: negative sign

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

Jared_Yuge
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

### Re: negative sign

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