3. Properties of Solids, Liquids and Gases
Property Solid Liquid Gas
Position
Expansion
Shape
Volume
Cmprsblty
Density
Mixing
4. Properties of Solids, Liquids and Gases
Property Solid Liquid Gas
Position Fixed Limited Random
Expansion
Shape
Volume
Cmprsblty
Density
Mixing
5. Properties of Solids, Liquids and Gases
Property Solid Liquid Gas
Position Fixed Limited Random
Expansion V. limited V. limited infinite
Shape
Volume
Cmprsblty
Density
Mixing
6. Properties of Solids, Liquids and Gases
Property Solid Liquid Gas
Position Fixed Limited Random
Expansion V. limited V. limited infinite
Shape Definite None None
Volume
Cmprsblty
Density
Mixing
7. Properties of Solids, Liquids and Gases
Property Solid Liquid Gas
Position Fixed Limited Random
Expansion V. limited V. limited infinite
Shape Definite None None
Volume Maintains Maintains Any
Cmprsblty
Density
Mixing
8. Properties of Solids, Liquids and Gases
Property Solid Liquid Gas
Position Fixed Limited Random
Expansion V. limited V. limited infinite
Shape Definite None None
Volume Maintains Maintains Any
Cmprsblty In-compress Slightly Very
Density
Mixing
9. Properties of Solids, Liquids and Gases
Property Solid Liquid Gas
Position Fixed Limited Random
Expansion V. limited V. limited infinite
Shape Definite None None
Volume Maintains Maintains Any
Cmprsblty In-compress Slightly Very
Density High High Low
Mixing
10. Properties of Solids, Liquids and Gases
Property Solid Liquid Gas
Position Fixed Limited Random
Expansion V. limited V. limited infinite
Shape Definite None None
Volume Maintains Maintains Any
Cmprsblty In-compress Slightly Very
Density High High Low
Mixing Xtrmly slow Slow Fast
12. What are some phase changes
Solid Liquid melting
Liquid Solid freezing
Liquid Gas vaporization
Gas Liquid condensation
Solid Gas sublimation
Gas Solid deposition
13. Endothermic / Exothermic
Processes that give
off energy are called
exothermic.
Processes that absorb
energy are called
endothermic
14. Endothermic or Exothermic ???
Solid Liquid melting Endothermic
???
Liquid Solid freezing ???
Exothermic
Liquid Gas vaporization Endothermic
???
Gas Liquid condensation Exothermic
???
Solid Gas sublimation Endothermic
???
Gas Solid deposition Exothermic
???
15. Relate this to weather …
Condensation of water vapor to rain
drops gives off heat – exothermic.
Evaporation of water to form water
vapor absorbs heat, and cools the
surroundings – endothermic.
The formation of snow from water
vapor gives off heat – exothermic.
16. Phase changes and the …
transfer of energy
Suppose you put a few drops of
alcohol on the back of your hand?
Why does it feel cold?
Evaporation is an endothermic
process and absorbs heat from the
surroundings, your hand.
18. Vapor Pressure
1. Consider a sealed container with water.
1 2 3
2. Some of the water 3. Some of the water
evaporates to make vapor condenses to
water vapor make liquid water
19. Water / water-vapor equilibrium
A dynamic equilibrium
is established when the
vapor rate at which liquid
water evaporates into
water vapor equals the
rate at which water
water
vapor condenses into
liquid water.
20. The pressure of the
water vapor varies with the
Pressure gauge
temperature.
vapor
Temp.
Digital
Thermometer
Pressure
23 C
water
22. Boiling occurs at the
temperature where the
vapor pressure of the
liquid equals the
ambient pressure.
23. What is the boiling point of water here?
Look at a Water boils at sea level at
vapor pressure 100 C where the ambient
table. pressure is 760 mm Hg.
The ambient Therefore, water
pressure here is must boil between
usually less than 95 C and 100 C,
700 mm Hg. usually around 97.5
24. Temperature
Corresponding
vapor pressure in
mm Hg (or Torr)
At 100 C the
vapor pressure
is 760 mm Hg
25. Therefore water
boils at 100 C
when the vapor
pressure of water
equals the
ambient pressure
of 760 mm Hg
26. Water boils at
the temperature
where the vapor
pressure equals
the ambient
pressure.
29. At different pressures …
When the ambient pressure is very
low, water can even boil at room
temperature.
If the ambient pressure is
17.5 mm Hg…
…water would boil at 20.0 C.
30. Temperature
Corresponding
vapor pressure in
mm Hg (or Torr)
31. At different pressures …
When the pressure is much higher
than normal atmospheric
pressure, water can stay liquid at
temperatures much higher than
the normal boiling point, as in
your car radiator.
33. Heat of Fusion
Fuse means “to melt”
The heat of fusion is the heat
needed to melt one gram of a
substance at the melting point.
The heat of fusion of ice can be
found experimentally.
34. Latent heat
Sometimes the heat of fusion or
heat of vaporization is called the
latent heat, or the latent heat of
fusion or vaporization.
Latent heats can use the following
symbols: Lf or Hf
Lv or Hv
35. Suppose you had a hot cup
of coffee …
… and you wanted to cool it.
You could …
1. Blow on it.
2. Stick it in the refrigerator
3. Add ice to it.
36. By adding ice …
… you cool the coffee because
the ice melts at 0.0 C,
extracting heat from the coffee,
and cooling the coffee.
The amount of cooling can be
calculated using the
heat of fusion of ice.
37. Measuring the heat of fusion of ice
Add ice
Add ice to calorimeter Ti of hot
Temp. water
probe
Tf of all
Time
water
All ice
melts
Calorimeter
Temperature
with hot water
38. The calculations are based
on conservation of energy.
The heat lost by the hot
water is equal to the heat
gained by the melting ice
and the water that comes
from the ice.
39. Q lost = Q gained
m hw c∆Thw = m i H fus + m i c∆Tiw
Heat gained Heat gained by
Heat lost by hot
by ice as it “ice water” as
water as it cools
melts to make it warms from
water at 0.0 C 0.0 to Tf
Hfus = heat of fusion hw = “hot water”
i = “ice” iw = “ice water” c = 4.18J/gC
Solve the equation for Hf
40. Solve for Qf
the heat of fusion
Q lost = Q gained
m hw c∆Thw = m i H f + m i c∆Tiw
m hw c∆Thw - m i c∆Tiw
Hf =
mi
41. Heat of fusion data
1. Mass of calorimeter cup
2. Mass of cal cup and hot water
3. Mass of hot water
4. Initial temperature of hot water
5. Final temperature of all water
6. Mass of cal cup and all water
7. Mass of ice added
42. Procedure
1. Heat up water on hot plate
2. Set up computer, load calibration file
3. Set up “Graph in real time” parameters
4. Mass calorimeter cup
5. Add hot water and mass cup
6. Get baseline temp. of hot water (~ 45 s)
7. Add ice – monitor temp – get Ti and Tf
from “Plot graph” and “examine data”
8. Mass calorimeter cup and all water
44. Heat of fusion
Absorbs 334 J
per gram
Ice at Melts (fuses) Liquid
0.0 C water at
Freezes
0.0 C
Releases 334 J
per gram
Hf = 334 J /g (80 cal/g)
45. Heat of vaporization
Absorbs 2260 J
per gram
Liquid Vaporizes Water
water at vapor at
Condenses
100. C Releases 2260 J 100. C
per gram
Hv = 2260 J /g (540 cal/g)
46. Sample problem
Find the amount of heat
needed to take 20.00 grams of
ice at 0.0 C, melt it, heat it up
to 100.0 C and completely
boil it away at 100.0 C.
47. Solution – think about it
Ice at 0.0 C melts, which takes
334 J per gram,
48. Solution – think about it
Ice at 0.0 C melts, which takes
334 J per gram, then it heats
up to 100.0 which takes 4.18 J
per gram per degree,
49. Solution – think about it
Ice at 0.0 C melts, which takes
334 J per gram, then it heats
up to 100.0 which takes 4.18 J
per gram per degree, then the
water boils which takes 2260 J
per gram.
50. Solution – formulas and numbers
Q tot = mH f + mc∆T + mH v
Q tot = (20.00 g)(334 J/g) +
(20.00 g)(4.18 J/gC)(100.0 C) +
(20.00 g)(2260 J/g)
Q tot = 60,240 J
52. Initial Observations
A clear, colorless liquid has a strong,
alcohol-like odor. When placed on a
watch glass and ignited, it burns, but
not completely. Some nonflammable
liquid remains.
Is the liquid a pure substance?
Is the liquid a mixture?
Heterogeneous or homogeneous?
53. How could you separate a
mixture of two clear,
colorless liquids?
What if the liquids
have different
boiling points?
55. Heating curve
for a liquid
Temperature hits a
plateau as liquid
temperature
boils
Boiling point of liquid
time
56. Heating curve
for a liquid
Temperature rises
when all liquid is
temperature
vaporized
Boiling point of liquid
time
57. Heating curve for two
liquids, A and B
Boiling point
time
of liquid B
Boiling point of liquid A
58. Fractional distillation can
be used to separate the
mixture into its various
“factions”.
Isolate each fraction at
each of the different
boiling points.
59. Collecting the first fraction
B
3
A Collect in the
time
2 first test tube
1
what comes off
in region 1.
60. Collecting the second fraction
B
3
A Collect in the
time
2 second test tube
1
what comes off
in region 2.
61. Collecting the third fraction
B
3
A Collect in the
time
2
1 third test tube
what comes off
in region 3.
62. Predict what is in each tube
Test tube 1 May contain only A
B
Test tube 2
A May contain both
time
3 A and B
2
1
Test tube 3
temperature May contain only B
63. Equipment setup for doing
Ring stand fractional distillation.
and finger
clamp thermometer or temperature probe
sidearm
boiling Jones condenser
flask
beaker or
hot plate test tube
64. Change the test tube in the beaker to
Ring stand collect each fraction
and finger
clamp thermometer or temperature probe
sidearm
boiling Jones condenser
flask
beaker or
hot plate test tube
65. Test the contents of each
test tube for …
1. Odor – does it have an odor?
Is it strong or weak?
2. Flammability – does it burn?
A lot or a little?
Test by place a small amount on a watch
glass and igniting it with a match.
