Hello, again. So, now we've covered a lot of the basics of kinetics. That's what we did last week. We looked, in particular, at the rate of the reaction in detail. We've looked at how the stoichiometry of a reaction is really important in trying to understand those rates. And then, we moved on to look at the order of reaction, which is how the reaction rate depends upon the concentration in a reaction. And we concentrated on some very simple cases of zero order, first order, and second order processes. We looked at how we could determine those by making the relative plots, straight line plots, by plotting the desired function against time. And then we looked at how we could do that experimentally. How we could measure reactions that were very fast, and reactions that were particularly slow. We then finally went on to look at the important effect of temperature on the reaction, how, when you increase the temperature the rate, generally speaking, will go up. And from those measurements we were able to determine the activation energy for the process. Now, in the second week, we are going to look at much more complex systems, much more like real life. So, we will start by looking at some equilibrium processes, then we will move on to some things that are ubiquitous in chemistry, and that is whereby a reaction occurs in a series of steps, one step, and then another step, and then another step. These are quite complicated and difficult to work out the reaction kinetics. So, what we will be looking for here are some important approximations that we can make. We'll look in detail at which are the most important steps, called rate determining steps, in the process. And then we'll look at some mathematical treatments which allow us to really simplify very complicated processes. We'll go on to look at chain reactions. And then finally, we'll look at the effect of adding catalysts to the system in order to speed up the reaction. So, that's what we are going to look at in the second week. And let's start by looking at complex reactions and equilibria. [BLANK_AUDIO]