[pantsaregood]

In my Chemistry class, I am required to design a lab experiment. I've decided to create phase diagrams for two compounds which, under standard pressure, behave similarly.

I've found some problems with this, though. The Chemistry lab at my college isn't funded well. We're quite limited as far as chemicals go. I may have to settle for two random compounds instead of similar ones.

The other problem, which I need help with, is that I'm unsure of how I should go about creating a phase diagram. I have access to a vacuum pump, but how do I know what temperatures/pressures to record?

Starting from nothing, how would I create a phase diagram?