SOLID
LIQUID
GAS
Well separated
Close together
What causes
a
substance
to
with no regular
with no regular
arrangement.
arrangement.
be in solid
or
liquid
state?
Vibrate and
Vibrate, move
move freely at
about, and slide
Attractivepast
forces
between
high speeds
each other
particles.
Tightly packed,
in a regular
pattern
Vibrate, but do
not move from
place to place
SOLID
LIQUID
GAS
Well separated
Close together
How do we
overcome
these
with
no regular
with no regular
arrangement.
arrangement.
attractive
forces?
Vibrate and
Vibrate, move
move freely at
about, and slide
By addingpast
energy
(heat)
to
high speeds
each other
the particles.
Tightly packed,
in a regular
pattern
Vibrate, but do
not move from
place to place








Temperature
boiling point
(l)  (g)-
100º C -
(l)  (g)condensation point
0º C -
melting point
(s)  (l)(s)  (l)freezing point
Energy Added
Temperature
“Fusion” means melting
(fusing bits of solid into
a liquid) when it is used
to talk about phase
changes.
Heat of vaporization
Heat of fusion
∆Hfusion
∆Hvaporization
Energy Added
Temperature
165º C  Kinetic energy (T) does not
increase during phase
change.
 The energy that overcomes
100ºattractive
Cforces between
particles is stored as
potential energy.
Heating
solid
(kinetic
energy)
0º C -25º C -
Latent
heat
(heat of
fusion)
(potential
energy)
Heating
liquid
Heating
gas
Latent heat
(heat of
vaporization)
(kinetic
energy)
(potential
energy)
(kinetic
energy)
 Phase
change energy is
often called a “latent”
heat. (Latent = hidden)
Energy Added

melting point
Melting
Kinetic
Energy =
temperature

boiling point
Boiling
vapor pressure




boiling point



60 ºC

80 ºC

100 ºC

120 ºC
pressure.
Standard Pressure: 1 atm = 101.3
kPa = 760 mmHg

atmospheric








 Does spaghetti take more time or less time
to cook in Alpine, compared to San Diego?
 MORE time– because we cook it at a
slightly lower temperature.



Pressure

Temperature





Pressure

SOLID
GAS
Temperature


Pressure


SOLID
Every point
Every point
on this line is
on this line is
a MP & FP !
a BP & CP !
GAS

Temperature


Pressure

SOLID
Every point
on this line is
a SP & DP !
GAS
Temperature
Requires the input of energy
Examples: dry ice, iodine and snow
Sublimation of snow occurs more
readily under at high altitudes with
less air pressure, with dry winds.
Sublimation occurs (on a
small scale) in your
freezer– when things get
freezer burn.
(The opposite of sublimation)
 Requires the release of
energy.
 Deposition commonly occurs
when water vapor freezes to
form snow or frost.
 (On your windshield, for
example.)
 This also occurs in your freezer
with the freezer burn!
Deposition of iodine


Pressure

Standard Pressure

SOLID
GAS
Temperature



Pressure

SOLID
GAS
Temperature


Pressure

SOLID
GAS
Temperature
 The 1 atm line
crosses all
three phases,
so we
experience all
phases of
water.
 To reach the triple point, you would need a
vacuum chamber. (Or extreme high altitude.)
 As altitude increases, air
pressure decreases.
 As air pressure decreases
boiling point decreases.
At what altitude would your food
cook most quickly?
 Hint: at what temperature would it
cook most quickly?
 This is why boiling
ramen doesn’t
work well for
(high altitude)
High Adventure
camps
 The boiling water
is not as hot as
you hoped… so
cooking takes
forever.
Temperature
boiling point
(l)  (g)-
85º C -
(l)  (g)freezing point
2º C -
melting point
(s)  (l)(s)  (l)freezing point
Even in a raging bonfire,
your water will refuse to
get any hotter once it’s
boiling. 
Energy Added
 If only there
was a way to
increase the
pressure…
Pressure
cookers
do that! 
 They can boil water at a temp
above 100 ºC, so food cooks faster.
Evaporation




 Condensation can occur when molecules
go from gas to liquid at temperatures below
the boiling point.
 Molecules slow down and begin
to stick together. (Due to IMFs!)
 As they change from gas to
liquid, the molecules release
latent heat to the surroundings
 Condensation is a heating
process!
The release of energy from
condensation drives weather including
wind, thunderstorms, hurricanes etc…