EXERCISE 17

You have just heard news of a newly discovered minor planet orbiting the Sun..  Astronomers discover an atmosphere around this minor planet.  

The atmosphere around this minor planet is made up entirely of 
Substance X.  This substance can be solid, liquid or gas at a 
temperature of 273 K and a pressure of 0.006 Earth atmospheres.  The 
distinction between the solid and gaseous phases of Substance X 
disappears at a temperature of 647 K and a pressure of 260 Earth 
atmospheres.  A solid piece of Substance X will float in liquid 
Substance X.  Draw a phase diagram of Substance X, and label where on 
the diagram the substance will be solid, liquid or gas.  The diagram 
need not be to scale, but be sure to label the vertical and horizontal 
axes.