Energy Diagrams

an energy diagram can be thought of as a curved plot on a graph that illustrates the energies of reactant products and transition state as a reaction occurs. Now, here we have the basic layout for an energy diagram, and we're going to say here that reactant which we're going to re label as our are found on the left in the beginning, and products we're gonna label SP are found to the right at the end. So if we take a look here at this energy diagram at the very beginning, we have our reactions here and at the very end of the curb represents our products. Now, here are Transition State, which will abbreviate as t s. This represents the maximum or max energy structure along the reaction coordinate between reactant and products. So here, the very top of this curve would be our transition state. Now, sometimes they're transparent. State is referred to as the activated complex. So you may hear either term within lecture your reaction. Coordinate. This is just the progress of a reaction pathway that lies along the X axis. So here are reaction. Coordinate would be here. It looks at the entire chemical reaction as we go from reactant up to transition state down towards our products. Now here, we're going to say that the last time you should familiarize yourself with is activation energy sometimes referred to as our energy barrier. This is abbreviated as e sub A. This is just the minimum energy required for a reaction to occur here. It'll be here. A So e a is basically the distance from your reactant starting point up to your transition state. So when we're dealing with any typical type of energy diagrams, these are the important terms you need to remember when trying to describe the layout of this particular energy diagram.

What is the energy value for the product within the following energy diagram? Remember, here this energy diagram is a curb. It looks little bit different from what we might have saw earlier. But remember, at the end of the curve represents our products. So here is where our products lie. All we have to see is where in terms of our energy, don't do products line. If we look here, energy is on the Y axis. And here it resides on this line, which is 100 and 40 killer jewels. So here we say that our products possess an energy of killer jewels Here, the question doesn't ask for but if they wanted our is, remember at the start here or reside on 110 killer jewels. And remember, up here is our transition state. It looks like it's a little bit over 180 killer jewels. So keep this in mind. When you're looking at any particular energy diagram, we have our reactant our transition state and our products. Each of them are lie on some type of energy, uh, one or energy value for any given energy diagram

the speed of a chemical reaction is based on the height of the activation energy. Now here, activation energy, which is your energy barrier and abbreviated as e sub A equals your transition state. So abbreviate as t s minus, you'll react in line. So we're going to say here If we're to look at these diagrams, remember, this is your transition state. This is your reactant. This is your transition state. This is your reactant. From this, we can calculate the energy of activation for both of these curves. So if we were to do that, we'd say that the transition state up here looks like it's around 90. So this would be 90, And then the reaction line looks like it touches 20. So this would be 70 killer jewels for the activation energy. Remember, it's the difference between the two And then in our other curve. The transition state looks like it's 60, And the reaction line still looks like it's around 20. So that's 40 killer jewels. Yeah, so remember, it's the difference between the two, which represents our activation energy. Now, what's important here? We're going to say that the higher the activation energy than fewer reactive molecules have enough energy to convert into products. So we're going to stay here. A higher activation energy equates to a slower reaction, and a smaller activation energy equates to a faster reaction. Here. We just calculated the activation energy for two energy diagrams, this one being 70 kill a jewels and this one being 40. So remember the one that has the higher activation energy, where represent our slower reaction, and the one that has the smaller or lower activation energy would represent art. Faster reaction. So just remember we can use activation energy to give us a good idea of how quickly or how slowly any typical chemical reaction will go. So keep this in mind when calculating activation energy.

which reaction will occur in the shortest amount of time. So shortest amount of time really means which chemical reaction is fastest. So remember we talked earlier about speed and activation energy if we want the fastest chemical reaction, Well, that would mean that we want the lowest activation energy if we take a look here. Reaction A is 1 43 killer jewels Reaction be as 80 killer jewels and reactions. C is 215 killer jewels. The answer is B. Since it has the lowest activation energy, that would mean that it moves the fastest and therefore would have the shortest amount of time necessary to go to completion.

now looking at an energy diagram, we can also talk about stability of the chemical reaction itself. Here, we're going to say that stability is the difference in overall energy between the reactions and products and can determine the favorability. So how likely is this chemical reaction to occur for any type of chemical reaction? Now here, we're going to say that our overall energy, which is Delta E equals products minus react. It's now remember, for any typical energy diagram, our reactions are at the beginning, and our products are at the end. And we've kind of understood this idea of products minus reactant. For those of you have seen my videos on thermal chemistry. We've heard of this before when dealing with entropy, which is Delta H. This is when the overall energy is classified as thermal energy. So basically, instead of just writing the term energy where it's a broad idea of energy, where it could be thermal energy, cosmic energy, um, nuclear energy, you could be more specific and say, Delta H. In this case, we'd be saying that we're talking about specifically about thermal energy so you can have Delta e here or Delta H year. Same thing. Now here we said it Products minus reactions. If we take a look here, we can see that our product line here is at 10 killer jewels and then our reacted line looks like it's around 30 killer jewels. Subtracting them gives us negative 20 killer jewels. So here my difference in energy is negative. 20 killer jewels. A negative sign here for Delta E would also mean a negative sign for Delta H. So since we can interchange them, remember, a negative Delta H sign means that we're dealing with an exotic, thermic process. Remember, Exile Thermic means that our reaction releases energy. This is why our reactant are higher in energy and our products are lower in energy. Releasing the energy means that we're forming products that are lower in energy. On the other side, we have our product line. Looking like it's around 50, and then our reactant line looks like it's around. I'd say 15 or so. So here, when we subtract those two from each other, that gives us 35 positive. 35. Now we're going to say here that it's positive, which means it's endo thermic for Delta H. Remember Endo. Thermic processes mean we absorb energy. So are reacting to absorb energy, and as a result, we form products that are higher in energy. So that's why the curve moves up to represent the product line at the end. Okay, so keep this in mind. We can look at overall energy to give us an idea of what's more favorable. And in terms of these two graphs, it's always better to have products that are lower in energy. Because remember, in chemistry, lower energy means greater stability. So this chart this first chart, which has a negative delta p value or you can say as an exile thermic process, would be more stable overall than the other graph, which shows an increase in energy and an endo thermic process. Okay, so keep that in mind when looking at stability and energy diagrams.