[Music] in this video we're going to discuss kinetic and thermodynamic control kinetic and thermodynamic control is relevant for reactions with two competing pathways specifically the two competing pathways must have what is called a thermodynamic product and a kinetic product the thermodynamic product is more stable but has a greater activation energy the kinetic product is less stable but has a lower activation energy we can see how this works in this reaction coordinate diagram we have reactants and the reactants can go through two paths this red path and this blue path the red path results in the formation of the thermodynamic product the blue path results in the formation of the kinetic product as you can see the reactants it's the same reactants for both so same energy but the products the thermodynamic products are more stable they're at a lower energy state than the kinetic products which are less stable and are at a higher energy however the thermodynamic products have a greater activation energy if you look at the amount of energy that the reactants have to absorb to reach the transition state for the thermodynamic product it's greater than the activation energy for the kinetic product and as we know activation energy is inversely related to the reaction rate so that means the kinetic product is formed faster and the thermodynamic product is formed more slowly however this is a competing thought right kinetic product is formed faster which is good but it's also less stable which is bad whereas the thermodynamic product it is more stable which is good but forms slowly which is bad and as it turns out there are reaction conditions that can be altered to preferentially favor the formation of one of these two products so for the kinetic product you can favor the formation of this product if there is low energy so there is not enough energy to exceed the activation energy barrier for the thermodynamic product then only the kinetic product can be formed and second if you have short reaction times so there isn't time to form the thermodynamic product so we say here the kinetic product is favored by low temperatures or favored with lower temperatures and short reaction times the thermodynamics product is essentially the opposite it is favored by higher temperatures and longer reaction times so when you're encountering an mcat question where there's more than one product that can be formed you want to keep in mind are there differences in the stability of the products are there differences in the activation energy that might indicate that the question is asking about kinetic versus thermodynamic control in which case you then want to think about the conditions did they use high or low temperatures and when the reaction times short or long [Music] you