1. Triple Point Plot melting freezing liquid solid Pressure (atm)
vaporization
condensation
Pressure (atm)
0.6
2.6
sublimation
deposition
gas
Temperature (oC)
LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 488

2. Triple Point Water 22,058 Critical point Critical pressure Normal
melting
point
Normal
boiling
point
101.3
Pressure (KPa)
Solid
Liquid
Vapor
Remind students of the effects of temperature and pressure on the state of matter. Students are familiar with the three states ofwater.
What happens to the boiling point of water as pressure increases?
(It increases.)
What happens to the freezing point as the pressure increases?
(It decreases.)
What is the triple point
(The temperature and pressure at which all three states coexist in equilibrium.)
0.61
Triple point
0.016
100
373.99
Critical
temperature
Temperature (oC)

3. Triple Point of CO2