Kinetics vs. Thermodynamics

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Jessica Tsui 1H
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Joined: Fri Sep 28, 2018 12:21 am

Kinetics vs. Thermodynamics

Postby Jessica Tsui 1H » Wed Feb 27, 2019 11:29 pm

In class, Lavelle said when the activation energy is high, the reaction happens very slowly because kinetics, not thermodynamics, controls the reaction. What did he mean by kinetics rather than thermodynamics controlling the reaction?

Dimitri Speron 1C
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Re: Kinetics vs. Thermodynamics

Postby Dimitri Speron 1C » Thu Feb 28, 2019 5:28 am

What he meant is that despite the fact that the compound is technically thermodynamically unstable, its kinetic stability trumps that, and the reaction either does not proceed or does so exceedingly slowly.

Luc Lorain 1L
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Joined: Fri Sep 28, 2018 12:18 am

Re: Kinetics vs. Thermodynamics

Postby Luc Lorain 1L » Sat Mar 02, 2019 4:49 pm

The thermodynamics of a reaction do not predetermine the kinetics of the reaction, and vice versa. Rather, these processes are two descriptors of the progression of a chemical reaction, describing the spontaneity and rate that the reaction possesses, respectively.

As an inverse to the diamond example, a reaction that has a very high delta G (thermodynamically unfavorable) but is kinetically unstable will likewise proceed very rapidly once enough energy had been supplied to overcome the EA of reaction.

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Re: Kinetics vs. Thermodynamics

Postby AdityaGuru1H » Sat Mar 02, 2019 6:07 pm

There can basically be 3 situations
The substance is thermodynamically stable so even over a very long period of time it will still stay the same under the same condition
The substance is not thermodynamically stable but is kinetically so for the time period that we are worried about the substance will stay the same but over a very long period of time, can be 1000 years+, then it might change.
The substance is neither thermodynamically stable or kinetically stable so when left alone it will change into something else

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