1. STATES OF MATTER
CHAPTER 13

3. Kinetic Theory of Matter
Kinetic refers to motion
All particles of matter are in motion; even solids
The motion of particles depends on their phase and the intermolecular forces between them.

4. The 3 States LIQUID SOLID GAS Medium/strong forces of attraction
Slip & slide random motion
SOLID
Strongest forces
Vibrating in place
Limited motion
Lowest KE
GAS
Weakest forces of attraction
Highest KE
Random motion

5. The Kinetic Theory Model for GASES
There are 3 fundamental assumptions about gases
1.) The particles of a gas are considered small, hard spheres with insignificant volume.
2.) The motion of gas particles is rapid, constant, and random.
3.) All collisions between particles in a gas are perfectly elastic (don’t lose KE).

6. Gas Pressure
Gas pressure is the result of the force that is created when gas particles collide with other bodies.
An EMPTY space with no particles have
No collisions. Therefore, there is
NO PRESSURE! This is called a:
VACUUM

7. Atmospheric Pressure
The pressure created by the atoms/molecules in Earth’s atmosphere and the collisions of these particles with other objects.

8. Atmospheric pressure changes with altitude!

9. Atmospheric pressure is measured with a BAROMETER!

10. Units for air pressure mm Hg Torr psi (lbs/in2) atm (atmospheres)
kPa (kilopascals)

11. Standard Atmospheric Pressure
YOU MUST MEMORIZE!!
These are the pressures at 0oC and sea level.
1 atm
760 mm Hg = 760 Torr
14.7 psi
101.3 kPa

12. Kinetic Energy & Temperature
Temperature is a measurement of the AVG kinetic energy of the particles.
Hotter temperature = higher avg KE, faster moving
Colder temperature = lower avg KE, slower moving

13. Thermometers!

14. Three Temperature Scales

15. Kelvin Scale ABSOLUTE ZERO It is 0 K which is equal to -273.15oC
The Kelvin Scale contains a special temperature:
ABSOLUTE ZERO
It is 0 K which is equal to oC
Which is approximately -460oF
It is the coldest possible temperature in the universe!
They have measured close to absolute zero in space ~ 1 K

17. LIQUIDS Liquids have a DEFINITE volume but no definite shape.
The stronger forces of attraction keep the particles in a liquid close together.
Liquids are more DENSE than gases b/c the particles are closer together.

18. EVAPORATION VS VAPORIZATION

19. VAPOR PRESSURE
This is the pressure that is caused by the gas particles above a liquid.

20. VAPOR PRESSURE & TEMP
HIGHER
VAPOR PRESSURE

21. BOILING POINT The temperature at which the vapor pressure of the
liquid is equal to the atmospheric pressure!!
NORMAL boiling point is the boiling point of the liquid at standard pressure.

22. VAPOR PRESSURE CURVES
NORMAL
BOILING
POINTS

23. Boiling points change with altitude!
If atmospheric pressure is lower, than the liquid will boil at a lower temperature.
Water boils below 100oC in Denver! That’s why there are different cooking times on boxes of noodle dishes.

25. SOLIDS
The particles in a solid have fixed positions, particles are tightly packed, not easily compressed, densest of the three phases, and particles vibrate in place.
Definite shape and volume
As solids are heated, the particles vibrate faster and spread apart a little.
Heating solids causes expansion.

26. Two types of solids
CRYSTALLINE
AMORPHOUS

27. Crystalline solids
have a very ordered
arrangement of the
particles. (UNIT CELL)
Amorphous solids lack an ordered arrangement.

28. Which is which?

29. ALLOTROPES
Allotropes are two or more different forms of the same element.
CARBON

30. PHASE CHANGES

32. DURING PHASE CHANGE – THE TEMP DOES NOT CHANGE!
HEATING CURVES
DURING PHASE CHANGE – THE TEMP DOES NOT CHANGE!