 Okay, so like I was saying last week, we were talking about something like this, reaction progress or reaction coordinate diagrams, right? And we were talking about, effectively, one step reactions where we were going from a reactant to a product, like our reaction was A to B, right? And we had a one hump, right? With the activation energy, we were calling this EA or delta G double dagger, right? And then we were calling this delta G here. Sometimes you'll see this delta GRXN or delta GR, things like that. That just means the delta G is a reaction, right? This is an exothermic reaction. Why? Because it's delta G is negative, right? So heat is being given off. So the reactants are at a higher level than the process, okay? So we're going to talk about, so this is a one step reaction. So now we're going to extend this to two step reactions. You can come for you lemons. Two step reactions, okay? So in a one step reaction, of course, that one step is the rate determining step because there's no other steps, okay? So it's like, you know, I don't know. Anything that you do in one step, right? You can imagine a lot of things. Okay, so let's erase this and compare this to a two step reaction. We'll do a two step exothermic reaction. So instead of going directly from A to B now, it's going to go from A and in between there, there was a transition state, remember? But now it's going to go A to an intermediate to B. And in between that intermediate and B is going to be another transition state. And remember, transition states are always at the top of that energy diagram, okay? Remember? So we did put TS formally up on that one. But if you go look back at those other videos, we were, okay? So let's do this type of reaction, exothermic, okay? So how many steps? One, two. That's how I know, okay? So this is a two step reaction. So from A to intermediate to B. So we could draw it. So up here, in fact, in this case, we would call this transition state one. We would call this transition state two, just to say one comes before two. The transition state one would be up here. That would be the point at when A is converting to intermediate, which is down next. And then transition state two is going to be up there. And that's going to be the point at intermediate converting to B. Is everybody okay with that? Okay? So is everybody okay with saying, this is a two step reaction, right? By looking at this diagram, how can you tell that? Two humps, yeah, okay? So it's just like the one hump camel and the two hump camel. Remember what we were talking about, okay? So remember the same, all the same notation applies though, okay? So if I say this difference from reactants to products, what's that going to be? Delta G, right? And since it's going down, it's going to be what? Negative. Okay? So remember what we called from the starting material of the reactants to the transition state up there? What do we call that? Activation. The activation energy, okay? Or EA, right? So or delta G double dagger, okay? So in this case, we would call this EA one, okay? Is that okay with everybody? So EA two, hopefully everybody could pick this out on their own, but it's going to be from this point up to this transition state because this is like another reaction happening, okay? So in fact, a two step reaction is actually what it is. One reaction occurred, then another reaction occurred, okay? It's like when we were walking across a river, right? We had to go on one rock and then go on the next one, okay? That's two steps, okay? So you can kind of put them into two little categories, okay? So this step also has an activation energy or delta G double dagger two. And in this case, right, we actually have, we can say, well, there's two steps. So one of them must have taken longer than the other one, okay? One of them takes a longer time than the other one, okay? So remember, it's just like pushing a boulder up the hill, right? This is going to take energy to push this boulder up the hill. But once I push it up to here and then I push it off, what's going to happen? It's going to go down there and it's going to slow down when it gets here, but it's going to just keep going, right? It's going to have so much energy going across, okay? So this step here takes very little time relative to this step. Does that make sense? Okay? So we call this one, in fact, the whole thing, right, not just the side of it, the rate of determining step, okay? So from A to I, step one is the rate of determining step, okay? It's not this actual point from the perfect step. Is everybody okay with that? So again, with a one-step reaction, that's the rate of determining step, because there's only one step. Is everybody okay with that? Are there any questions on this? Which part makes the bang? The bang? Yeah. So it's going to be the one that gives off the most energy, right? So it's actually the whole thing, right? So honestly, once you get up here, you're giving off the most energy, but the difference in energy is from here to here, you know? So you're inputting a little bit more energy. That activation energy is just a little bit, but it's this that gives off the bang, if you will.