SECTION SUMMARY
13.4 Changes of State Summary:
The change that occurs when a solid goes directly to the gas or vapor state without
first becoming a liquid is sublimation. This change can occur because solids, like
liquids, have a vapor pressure. Substances that sublime include iodine and solid
carbon dioxide (dry ice).
A graph that shows the relationship between the states of a substance is called a phase
diagram. On this diagram, a line between two phases shows the conditions at which
the phases are in equilibrium. The triple point is the only set of conditions at which
solid, liquid, and gas phases coexist. The triple point for water is the temperature of
0.016 degree Celsius and a pressure of 0.61 kPa.
A phase diagram does not give information on changes in mass of solids, liquids, and
gases. Based on phase diagram, water can be made to boil at 1050C by increasing
pressure.
13.4 Changes of State Vocabulary Terms:
melting:
the change of a solid to a liquid state
freeze drying:
a method or removing water from food, using
sublimation
phase diagram:
graph that shows the relationship among the states
of a substance
0.016oC and 0.61 kPa:
temperature and pressure of the triple point of water
sublimation:
the change of a solid to a vapor without passing
through the liquid state
100oC and 101.3 kPa:
the temperature and pressure at the normal boiling
point of water
triple point:
the only point describes the only set of conditions at
which all three phases can exist in equilibrium with
one another
The End of the Summary