Phase Changes : Opener: Up until now, we’ve talked about the three phases of matter. However, from our own personal experience we know that solids can become liquids and that liquids can become gases. How does this work ?. Solid Liquid transformations:
When the vapor pressure of the liquid becomes equal to the atmospheric pressure, this means that the average energy of all the particles has become greater than the amount of energy needed to enter the vapor phase.
Boiling point: The temperature at which this happens.
Triple point: The conditions of pressure and temperature at which all three phases of matter can stably coexist. For water this is 0.006 atm and 0.010 C, which makes it impossible to observe without special equipment.