Relationship between Gibbs free energy and E


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Shanzey
Posts: 120
Joined: Wed Sep 18, 2019 12:20 am

Relationship between Gibbs free energy and E

Postby Shanzey » Fri Feb 21, 2020 8:47 pm

Is Gibbs free energy only related to E using the equation (delta)G^o = -nFE^o? In addition, does the spontaneity of a reaction affect E?

Chris Tai 1B
Posts: 102
Joined: Sat Aug 24, 2019 12:16 am

Re: Relationship between Gibbs free energy and E

Postby Chris Tai 1B » Fri Feb 21, 2020 10:22 pm

The (delta)G^o = -nFE^o equation is one of the equations that relates Gibbs free energy to E. I like to think of it as the value of E affecting the spontaneity of a reaction, instead of the spontaneity of the reaction affecting the value of E (althought I suppose this is a potential way of interacting with this equation).
Hence, if the value of E is positive, then there is a potential difference and an ability for the given cell or battery to perform some form of work. This means that in the equation (delta)G^o = -nFE^o, if we substitute some kind of positive value in for E, then the value of (delta)G^o will be negative. which makes sense because the reaction will be spontaneous if the E value is positive.

Sofia Ban
Posts: 80
Joined: Fri Sep 28, 2018 12:25 am

Re: Relationship between Gibbs free energy and E

Postby Sofia Ban » Sat Feb 22, 2020 9:45 am

Yes, there is that equation, but this equation can also be changed to include values for R constant, temperature, and the concentration of the products and reactants. Well, based on the equation, the spontaneity of the reaction would affect E since having a negative value for delta G (spontaneous) would mean that cell potential would have to be positive. This makes sense because for constant temperature and pressure, delta G would equal the maximum work as well.


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