### Units G=-nFE

Posted:

**Fri Mar 06, 2020 8:17 am**I'm not sure if this is common sense, but if the units for F are coulombs and the units for E are volts, how do we get joules for G?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=141&t=61443

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Posted: **Fri Mar 06, 2020 8:17 am**

I'm not sure if this is common sense, but if the units for F are coulombs and the units for E are volts, how do we get joules for G?

Posted: **Fri Mar 06, 2020 9:44 am**

The units cancel out because volts, coulombs, and joules are all interrelated -- one joule is equal to one volt times one coulomb.

Posted: **Fri Mar 06, 2020 10:32 am**

The units of Volts are actually equivalent to Joules/Coulomb. So, if you work out the math, the units should all cancel and you will get Joules.

Posted: **Fri Mar 06, 2020 1:01 pm**

1 Volt = 1 J/C so the units cancel out when you multiply;

substituting the units in for -nFE, you get

-(mol)x(C/mol)x(V=J/C), and you’re left with J for G

substituting the units in for -nFE, you get

-(mol)x(C/mol)x(V=J/C), and you’re left with J for G

Posted: **Fri Mar 06, 2020 3:15 pm**

Volts = Joules/Coulomb so in deltaG=-nFE the Coulombs cancel out from the multiplication between E (J/C) and F (C/mol), and n has no units so the final units will be J/mol.

Posted: **Fri Mar 06, 2020 8:31 pm**

F is also Coulombs/mol and Volts is Joules/Coulomb. When multiplied together, the units cancel out leaving Joules for deltaG

Posted: **Fri Mar 06, 2020 9:10 pm**

Zaynab Hashm 2I wrote:1 Volt = 1 J/C so the units cancel out when you multiply;

substituting the units in for -nFE, you get

-(mol)x(C/mol)x(V=J/C), and you’re left with J for G

Does n have units? I have seen some TAs and UAs write mole of e- when plugging in the numbers into n in that equation. But I have also heard that n does not have units and that is why we end up with J/mol as our final units for delta G. Could someone clarify this for me, please?