Calculating Gibbs Free Energy Equations






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annabel 2A
Posts: 67
Joined: Fri Sep 28, 2018 12:18 am

Calculating Gibbs Free Energy Equations

Postby annabel 2A » Mon Feb 18, 2019 4:41 pm

For 6th Edition Chapter 9 #55: Write a balanced chemical equation for the formation reaction of (a) NH3 (g); (b) H2O(g); (c)CO(g); (d) NO2(g). For each reaction, determine H,S, and G from data in Appendix 2A.

When calculating the Grxn, can we use the equation "deltaG = deltaGformation(products) - deltaGformation(reactants)"?
The solutions manual uses the equation "deltaG = deltaH - TdeltaS" and the answer is 0.05 kJ/mol off from what I got when I used the other equation.

Kessandra Ng 1K
Posts: 67
Joined: Fri Sep 28, 2018 12:25 am

Re: Calculating Gibbs Free Energy Equations

Postby Kessandra Ng 1K » Mon Feb 18, 2019 4:44 pm

I think you can use both, and they should give similar (but not necessarily the same) answers. Since you've already found ∆H and ∆S, then it would make sense to use the ∆G = ∆H - T∆S equation.

Cole Elsner 2J
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

Re: Calculating Gibbs Free Energy Equations

Postby Cole Elsner 2J » Mon Feb 18, 2019 4:46 pm

Both of these methods work! In the end it's all a state function so your path is up to you. With these problems just try to make the most out of what's GIVEN to you.


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