1. Section 1: States of Matter & Phase Changes
Unit 10: States of Matter
Section 1: States of Matter & Phase Changes

2. IMAFs KE vs. States of Matter main difference between phases is…
GAS
LIQUID
SOLID
main difference between phases is…
the distance between particles…
…which depends on two competing quantities: KE
(kinetic energy of the particles)
IMAFs
(intermolecular attractive forces between particles)
vs.

3. K = oC + 273 no KE Temp↑ as KE↑ Temperature
average KE is directly proportional to temperature in Kelvin
Temp↑ as KE↑
373 K
273 K
K = oC + 273
no KE
0 K
absolute zero
–273oC
–460oF

4. SOLID - definite shape - definite volume - low kinetic energy
VLC – media file (Changes of State)
- low kinetic energy
- particles vibrate in place

5. LIQUID - indefinite shape - definite volume - higher kinetic energy
VLC – media file (Changes of State)
- higher kinetic energy
- particles flow

6. GAS - indefinite shape - indefinite volume - highest kinetic energy
VLC – media file (Changes of State)
- highest kinetic energy
- expands to fill container
compressible

7. GAS SOLID LIQUID Phase Changes condensation sublimation deposition
Energy Absorbed
Energy Released
GAS
condensation
sublimation
deposition
vaporization
Video – Changes of State
melting
SOLID
LIQUID
freezing

8. liquid solid + energy liquid solid + energy
freezing:
l to s (lose KE)
liquid solid + energy
Forces of attraction between molecules cause them to get closer, then vibrate about fixed positions and form a solid.
liquid solid + energy
melting:
s to l (gain KE)

9. energy + liquid gas vaporization: evaporation: l to g at surface
boiling:
l to g beneath surface

10. gas liquid + energy condensation: g to l (lose KE)
warm water vapor in air
ice cubes
cold water inside glass
condensed drops outside glass
Is water in glass cooler or warmer ?

11. Equilibrium
During a phase change, two opposing processes are happening
Example – water in an open system
More water molecules are escaping from the liquid and evaporating than are being caught by the liquid and condensing
The phases are NOT in equilibrium

12. Equilibrium
In a closed system, the rate of vaporization can equal the rate of condensation.
When the rates are equal the system is said to be in dynamic equilibrium.

13. Quick Quiz.
1) The average kinetic energy of the particles in a substance is directly proportional to the
A) molar mass
B) density
C) temperature
D) size 13

14. A) attract each other significantly B) are spaced relatively far apart
Quick Quiz.
2) Compared to liquids and solids, gases are easily compressed because the particles in a gas…
A) attract each other significantly
B) are spaced relatively far apart
C) are extremely small
D) move in constant, random motion 14

15. Quick Quiz.
3) What is –88oC in Kelvin temperature?
A) 185 K
B) 361 K
C) –361 K
D) 273 K
K = oC + 273
K = – 15

16. Quick Quiz.
4) Put a cup of water on a table. A process that will occurs is…
A) evaporation.
B) condensation.
C) BOTH A and B
D) NONE of the above