Now looking at an energy diagram, we can also talk about stability of the chemical reaction itself. Here we're going to see that stability is the difference in overall energy between the reactants 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 ΔE, equals products minus reactants.
Now remember, for any typical energy diagram, our reactants are at the beginning and our products are at the end. And we've kind of understood this idea of products minus reactants. For those of you who have seen my videos on thermochemistry, we've heard of this before. When dealing with enthalpy, which is ΔH, this is when the overall energy is classified as thermal energy. So basically instead of Justice writing the term energy where it's a broad idea of energy where it could be thermal energy, cosmic energy, nuclear energy, you could be more specific and say ΔH in this case, we'd be saying that we're talking about specifically about thermal energy. So you could have ΔE here or ΔH here. Same thing.
Now here we set it products minus reactants. If we take a look here, we can see that our product line here is at 10 kilojoules and then our reactant line looks like it's around 30 kilojoules. Subtracting them gives us -20 kilojoules. O here my difference in energy is 20 kilojoules. A negative sign here for ΔE would also mean a negative sign for ΔH. So since we can interchange them, remember, a negative ΔH sign means that we're dealing with an exothermic process. Remember, exothermic means that our reaction releases energy. This is why our reactants 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 looks 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 endothermic for ΔH. Remember, endothermic processes mean we absorb energy. So our reactants absorb energy and as a result, we form products that are higher in energy. So that's why the curve moves up to representing product line at the end, OK.
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 ΔE value or you can say as an exothermic process, would be more stable overall than the other graph which shows an increase in energy and an endothermic process. So keep that in mind when looking at stability and energy diagrams.