1. Kinetic molecular theory and liquids and solids

2. KMT of Liquids
Particles in constant motion, Particles not bound together in fixed position
Particles closer together so forces of attraction are more effective, therefore liquids are more ordered than gases
Fluidity – “can flow and take shape of container”

3. Characteristics of liquids
High density compared to gases
Incompressible, can only decrease volume by 4% at most
Ability to diffuse, the higher the temp (KE) the faster to diffuse

4. Characteristics of liquids
Surface tension – The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension
Capillary action – attraction of surface of liquid to surface of solid

5. Vaporization - Phase change
examples of VAPORIZATION
Evaporation – when particles escape from the surface of a non-boiling liquid and enter the gas state
Boiling – conversion of liquid to a vapor within the liquid as well as the surface

7. EVAPORATION ACCORDING TO KMT
Particle with higher than average kinetic energy – at the surface of the liquid – move faster
These particles can overcome the intermolecular forces that bind them to the liquid
They ‘escape’ into the gas phase
Application:
How is evaporation a crucial process in nature?

8. If enough Kinetic energy is removed from a substance
Attractive forces pull particles into orderly arrangement
Substance becomes a solid
Freezing (solidification)

9. KMT of solids Closely packed
Attractive forces hold particles in fixed positions with only vibrational movement around fixed points
2 types of solids
Crystalline – orderly geometric repeating pattern
Amorphous – randomly arranged particles

10. Characteristics of solids
Definite shape & volume
Definite melting point
High density
Not compressible
Low rate of diffusion – almost none

11. phase
A phase - part of a system that has uniform composition and properties.
(liquid, solid, gas)
Phase change = mixture of 2 phases at same time

12. Equilibrium What does the word equilibrium mean? A dynamic condition
2 opposing changes occur at equal rates in a closed system.

13. Pressure
Caused by the collisions of molecules with the walls of a container.
Gas molecules exert a pressure on any surface with which they collide
Depends on temperature, volume and number of molecules

14. Volatile liquids – evaporate readily , weak forces of attraction between particles
Nonvolatile liquids – don’t evaporate readily, relatively strong attractive forces

15. Equilibrium vapor pressure

16. Pressure exerted by a vapor (gas) over its liquid
Vapor Pressure
Pressure exerted by a vapor (gas) over its liquid

17. Equilibrium Vapor Pressure
Pressure - caused by the collisions of particles with the walls of the container
Equilibrium vapor pressure measured when there is equilibrium between gas and liquid phase.
rate of condensation = rate of vaporization
Number of particles going into vapor phase = number of particles continuing to go into liquid phase