Practice: A phase diagram for an unknown substance, X, is shown below. Using this diagram, answer the following questions.
a. Under atmospheric pressure, what is the sublimation point of X?
b. What phase is substance X in at (3 x 10 5 Pa, 60 K)?
c. Which phases can X exist in for temperatures above 80 K under pressures of 6 x 105 Pa or less?