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

Moderators: Chem_Mod, Chem_Admin

Vera Ong 3H
Posts: 26
Joined: Fri Jun 17, 2016 11:28 am

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

Postby Vera Ong 3H » Thu Mar 02, 2017 10:54 am

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?

mikezargari
Posts: 20
Joined: Wed Sep 21, 2016 2:56 pm
Been upvoted: 1 time

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

Postby mikezargari » Thu Mar 02, 2017 12:28 pm

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.

Ariana de Souza 4C
Posts: 99
Joined: Wed Sep 21, 2016 2:56 pm

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

Postby Ariana de Souza 4C » Thu Mar 02, 2017 5:52 pm

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...

Josephine_Tang_1N
Posts: 30
Joined: Wed Sep 21, 2016 2:57 pm

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

Postby Josephine_Tang_1N » Wed Mar 08, 2017 11:20 am

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.


Return to “*Free Energy of Activation vs Activation Energy”

Who is online

Users browsing this forum: No registered users and 1 guest