CHEMISTRY COMMUNITY

How can you tell whether kinetics or thermodynamics controls a reaction?

In general, short reaction times favor kinetic control while longer reaction times favor thermodynamic control

Short reaction times usually suggest kinetic control, and longer reaction times usually suggest thermodynamic reaction control. If a reaction is under thermodynamic control at a certain temp, it will also be under thermodynamic control at a higher temp for the same reaction time. If a reaction is under kinetic control at a certain temp, it will also be under kinetic control at any lower temp for the same reaction time.

Reactions that are carried out quickly (i.e. those with short reaction times) are said to be kinetically controlled while those carried out over longer periods of time are said to be thermodynamically controlled.

reactions that quickly react usually mean that it is controlled more via kinetics, while reactions that are carried out more slowly suggest that they are being controlled more via thermodynamics. this is also the reason why the terms spontaneous and nonspontaneous might be misleading,

https://m.youtube.com/watch?v=DrToRsXmjP4
The youtube video explains the difference useful to know when distinguish between thermodynamic and kinetic control.

annikaying wrote:How can you tell whether kinetics or thermodynamics controls a reaction?

For the reactions that are spontaneous but slow, I believe that kinetics control the reaction more. For reactions that are spontaneous but fast, I believe that thermodynamics control the reaction more. For reactions that are not spontaneous, they are defined more by thermodynamics.

reactions that are short are kinetically controlled while longer ones are thermo controlled

kinetically controlled reactions are usually short while thermo controlled reactions are long.

Reactions with short reaction times are usually controlled by kinetics, while reactions with longer reaction times are usually controlled by thermodynamics.

Thermodynamic-controlled reactions are usually long, while kinetic-controlled reactions are relatively quick.

Those controlled by kinetics are usually short and ones controlled by thermodynamics are usually longer.