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Delta G Double Dagger, Delta H Double Dagger, Delta S Double Dagger

Posted: Thu Mar 02, 2017 10:54 am
by Vera Ong 3H
Conceptually, why are delta G double dagger and delta H double dagger values always positive? Why could delta S double dagger be positive or negative? What are examples of situations for pos/neg situations for delta s double dagger?

Re: Delta G Double Dagger, Delta H Double Dagger, Delta S Double Dagger

Posted: Thu Mar 02, 2017 12:28 pm
by mikezargari
I'm pretty sure that the delta G and delta H double daggers are always going to be positive because they represent the amount of energy that is needed to overcome the activation barrier. If you have a reaction A+B->AB(double dagger)->C energy is required to first break the bonds of A and B so that they can react with one another hence the delta H double dagger's positive sign. Hope this helped.

Re: Delta G Double Dagger, Delta H Double Dagger, Delta S Double Dagger

Posted: Thu Mar 02, 2017 5:52 pm
by Ariana de Souza 4C
And I'm pretty sure you have delta S as negative because you're making the molecule into one particular orientation for it to be a transition state, so there is a decrease in entropy. I don't know why you would have a positive delta S though...

Re: Delta G Double Dagger, Delta H Double Dagger, Delta S Double Dagger

Posted: Wed Mar 08, 2017 11:20 am
by Josephine_Tang_1N
If this is referring to Section 4.4 in the green organic textbook, they state that all the statements they make reference the reaction in Figure 4.6, which is an SN2 reaction.