Types of energy profiles

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Monica Habashy 3A
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Types of energy profiles

Postby Monica Habashy 3A » Mon Mar 06, 2017 6:52 pm

How many types of energy profiles are there? I know there's an energy profile in terms of Gibbs free energy and one in terms of potential energy...are there any others we need to be aware of? What are the differences between the Gibbs free energy and the potential energy ones?

Chem_Mod
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Re: Types of energy profiles

Postby Chem_Mod » Mon Mar 06, 2017 6:59 pm

Monica Habashy 3A wrote:How many types of energy profiles are there? I know there's an energy profile in terms of Gibbs free energy and one in terms of potential energy...are there any others we need to be aware of? What are the differences between the Gibbs free energy and the potential energy ones?


The ones you need to be aware of are the ones for Gibbs free energy and for enthalpy.

Monica Habashy 3A
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Re: Types of energy profiles

Postby Monica Habashy 3A » Mon Mar 06, 2017 9:27 pm

for the Gibbs free energy diagrams, do we look at delta G of activation for the second step from the intermediates to the transition state or in terms of the reactants to the transition state.

Rachel Wile 2D
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Re: Types of energy profiles

Postby Rachel Wile 2D » Wed Mar 08, 2017 5:58 am

I believe we look at the delta G of the transition states relative to the reactants, even for the second step. However, when you are calculating activation energy of the second step you look at the the transition state relative to the intermediates. My TA said that some chemists look at delta G of the second transition state relative to the intermediates and that they will likely accept answers drawn either way.

Katherine_Zhuo_3B
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Re: Types of energy profiles

Postby Katherine_Zhuo_3B » Wed Mar 08, 2017 10:34 am

The potential energy profile is generally used by physical chemist's and refer to activation energy, while the free energy profile is generally used by organic chemists.

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Re: Types of energy profiles

Postby Chem_Mod » Wed Mar 08, 2017 11:06 am

Monica Habashy 3A wrote:for the Gibbs free energy diagrams, do we look at delta G of activation for the second step from the intermediates to the transition state or in terms of the reactants to the transition state.



This depends on which type of chemist you take to. You can either define it as the difference between the intermediates and transition state 2 (more common for physical chemists) or as the difference between the reactants and transition state 2 (more common for organic chemists). We will accept either answer as long as it is drawn and labeled properly.


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