In this lecture, we're going to talk about a concept called a closed cliperon relation. Now, vapor pressure is very important when we talk about this relation. So if you're not sure about vapor pressure, check out the video below. Now, the vapor pressure of a liquid increases with temperature. That means if you heat up a liquid, more molecules will evaporate, thereby increasing the vapor pressure of our liquid. Now, you could also graph vapor pressure versus temperature on an x y plane.