Topic: Chemistry
Aim: Explain the different types of phase
changes and the energy changes involved.
Do Now: ON NOTES SHEET
HW: Ditto – Periodic Tables Families Review
(last page of Periodic Table Notes Packet)
http://www.youtube.com/watch?v=XaDxwe8l3us&feature=related
Phase
Changes
• Involves the absorption OR
release of heat (energy).
Substance
absorbs
heat energy
Melting • Solid  liquid
• Solid ABSORBS heat
energy
Substance
absorbs
heat energy
Melting points of different substances
• Iron: 1536ºC
• Gold: 1063ºC
• Glucose: 150ºC
• Urea: 132-134ºC
Vaporization
•
•
•
Liquid  gas
Liquid ABSORBS heat
energy
When it occurs on surface of
liquid: evaporation
GAS
Liquid
absorbs
heat energy
LIQUID
Boiling points of different substances
• Alcohol (Ethanol): 79ºC
• Iodine: 184.3ºC
• Mercury: 356.9ºC
• Olive oil: 300ºC
• Jet fuel: 163ºC
Condensation • Gas  liquid
• Gas LOSES heat energy
GAS
Gas loses
heat energy
LIQUID
Freezing • Liquid  solid
• Liquid LOSES heat
energy
Substance
loses heat
energy
Sublimation • Solid  Gas
• No liquid phase
• Ex: dry ice
GAS
Solid
absorbs
heat energy
Solid
Moth balls commonly undergo the process of sublimation.
Sublimation is the process in which a solid changes directly to
its gaseous phase, skipping the liquid phase.
And an animation of the phase
changes of water
Let’s summarize…
1. List the different types of phase
changes.
2. Explain what happens to heat energy
in each phase change.
1. When a liquid becomes a solid,
energy
1. does not change
2. is released
3. is absorbed
4. is first absorbed, then released
2. _______ is the process in which
liquid changes to gas below the
boiling point.
1. Sublimation
2. Condensation
3. Evaporation
4. Combustion
3. On a hot day, the outside of a glass
containing a cold drink becomes frosty.
When touching the glass, it feels
1. water that has passed through the glass
2. water that has condensed from a gas in
the air
3. water that has solidified
4. water that has absorbed energy
4. The change of a liquid to a
solid is called
1. freezing
2. Melting
3. sublimation
4. vaporization
5. During which of the following
processes is there a decrease in the
heat content of the form of water
indicated?
1. Ice as it forms on a lake
2. Water droplets as they fall to the
ground
3. Water as it evaporates from a pond
4. Snow as it melts on a mountainside
6. When substances go directly
from the solid phase to the gas
phase, the phase change is
called
1. sublimation
2. condensation
3. evaporation
4. vaporization
E
D
condensing
100
Temperature º C.
boiling
C
B
freezing
0
melting
A
Heat (thermal energy)
• http://www.youtube.com/watch?v=vDZhUk
p30tE&feature=related