This document discusses phase changes of matter. It defines key phase changes - melting, freezing, vaporization, boiling, condensation, sublimation, and deposition - and explains the energy changes that occur during these processes. A diagram shows the phase changes between solid, liquid, and gas phases, and how heat absorption or release causes kinetic energy to increase or decrease during these transitions. Reverse phase changes occur at the same temperature, and when they occur at the same rate the phases are said to coexist in dynamic equilibrium at the triple point.

1. ENERGY AND MOLECULAR
ORDER CHANGES
PHASE
CHANGES

2. S
O
L
I
D
G
A
S
L
I
Q
U
I
D
Heat Energy Absorption / Kinetic Energy
Increase
Sublimati
on
Fusion Vaporizatio
n
(Melting) (Boiling)
Solidification Condensation
(Freezing) (Liquefyin
g)
Depositio
n
Heat Energy Release / Kinetic Energy
Decrease
DIAGRAM OF ENERGY CHANGES

3. MELTING POINT - the temperature at
which the solid melts to form the liquid
FREEZING POINT - the temperature at
which the liquid freezes to form the
solid

4. EVAPORATION / VAPORIZATION – liquid
particles that overcome the attractive
forces of the neighbouring particles and
escape the process, hence, becoming a
gas
BOILING POINT – when a liquid is heated
in an open container, its vapour pressure
will rise until it equals the pressure of
the atmosphere above the liquid causing

5. CONDENSATION – the reverse process,
happens when particles in the vapour
pressure are cooled and returns to liquid
SUBLIMATION – the solid phase passes
directly into the gas phase

6. DEPOSITION – the change from the gas
to the solid phase without passing the
liquid phase; the reverse of sublimation

7. Reverse phase changes occur at the
same temperature and if they occur at
same rate, the phases are said to
coexist in dynamic equilibrium.
Earning the title, “Triple Point”

8. SOLID LIQUID MELTING
SOLID GAS SUBLIMATION
LIQUID SOLID FREEZING
LIQUID GAS VAPORIZATION
GAS SOLID DEPOSITION
GAS LIQUID CONDENSATION