Question: In some reactions, two or more different products can be formed by different pathways. If the product formed by the faster reaction predominates, the reaction is considered to be under kinetic control. If the predominant product is the more thermodynamically stable, the reaction is considered to be under thermodynamic control. In the reaction of HBr with the reactive intermediate CH3CH£CHCH2, at low temperatures the predominant product is CH3CHBrCH£CH2, but at high temperatures, the predominant product is CH3CH£CHCH2Br. (a) Which product is formed by the pathway with the larger activation energy? (b) Does kinetic control predominate at low or high temperatures? Explain your answers.
Can someone explain the concepts behind answering part (b) to this question?
Chemical Kinetics Concepts (HW: 15.79)
Arrhenius Equation:
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Re: Chemical Kinetics Concepts (HW: 15.79)
Postby Katherine Ho 1E » Sat Feb 20, 2016 5:26 pm
Kinetic control predominates at low temperatures.
Because if the reaction occurs under kinetic control, that means that the product is formed by the faster reaction
and a faster reaction means that it has a lower activation energy and a larger rate constant due to that lower activation energy barrier.
On the other hand, if the reaction were thermodynamically controlled, that means that there was enough energy to overcome a higher activation energy.
Because if the reaction occurs under kinetic control, that means that the product is formed by the faster reaction
and a faster reaction means that it has a lower activation energy and a larger rate constant due to that lower activation energy barrier.
On the other hand, if the reaction were thermodynamically controlled, that means that there was enough energy to overcome a higher activation energy.
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