 It's instructive to look at the solubility as a function of temperature slightly more formally. So I'm gonna draw that Here I have an energy axis That goes from say Plus 10 kcal, sorry again for not drawing units to minus 10 and then there is a zero axis over here in the middle and Then an x-axis and I'm following Finkelstein and drawing that from roughly 0 degrees centigrade to a bit over boiling Maybe 150 degrees centigrade Now if I look at the simple hydrocarbon in this case, I think it's pentane The book uses but it's not super important which one it is There are three different components and we want to include all of them first We had the entropy part that we will draw as t-delta s and t-delta s went something from maybe well roughly t-delta s Plain boring linear the higher the temperature is the worst this effect is and it's you see here It's mostly from the temperature That's a it's a straight line meaning delta s is roughly constant We had a second part though. We had the enthalpy. What is the cost of bonds that we're forming now? That is something that may be Delta H So it's it goes up until we get to some sort of minimum there Sorry local maximum and Finally if we take the difference between delta H and t-delta s We would get delta G right and that might end up going something roughly like that Again, this is just qualitative There are two or three important things to take home here first delta G is virtually always a balance between many terms You see that coming back here both of them are negative here both of them are positive It's only in this area that it's obvious that I'm gaining here and gaining from the entropy And in general you that means that you need to understand both of them. You need to understand the balance The second part is that you see that you have a local maximum of delta G here In this case you had had high pressure to reach temperatures this high but If this is now oil impasta water That would mean that it would be more and more and more difficult to solve with oil until you get to some point And then it starts to get better again That maximum occurs when delta s is zero why? Well remember that comes out straight from this definition that we had before that the entropy s was minus the derivative of G with respect to temperature, right? And that's what we had on the x-axis So if the derivative of this curve is that one The max has to be when the net difference in entropy is zero We will come back to this when we talk about proteins because it's going to turn out solve for proteins to fall That's kind of the opposite of putting hydrocarbons in water. I know how straight that sounds, but it will make sense next lecture I think