Transition State delta G??

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Amy Pai
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Joined: Fri Sep 25, 2015 3:00 am

Transition State delta G??

Postby Amy Pai » Wed Feb 24, 2016 5:35 pm

Ashely went over in her lecture the activation complex graph, and I was a bit confused as to why the delta G she drew for TS 2 went from the energy level of the reactants to the peak of TS2 (instead of maybe from the intermediate to the peak of TS2). I guess I'm just confused as to how "delta" doesn't look like "final"(TS peak) - "initial"(Intermediates).

Can someone clear this up for me? Or are TS relevant to the reactants?? But the the order of reaction can't be flipped because what forms what at what step is important....

Chem_Mod
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Re: Transition State delta G??

Postby Chem_Mod » Thu Feb 25, 2016 10:30 am

It has to go from the free energy of the reactants to the hump (whether its the first or second) because it will still be the same net energy put into the system in order to reach that peak. If you think about it, going from the starting energy level, to the first peak, then back down, then up to the second peak is going to equal the same energy as just going from starting energy level to the second peak (net change).

I attached a picture to help clarify what I am saying. In this picture, if you go from reactant to TS2, it is a change of 8 units. If you go up five to the first hump, down 2, then back up 5 for the second hump the net change is still 8 units.

FullSizeRender.jpg


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