1. Solids, Liquids and Gases
Chapter 16--
Solids, Liquids and Gases

2. Section 1—Kinetic Theory
Kinetic Theory—an explanation of how particles in matter behave
All matter is composed of small particles
Particles are in constant random motion
Particles are colliding w/ea other and the walls of their container
Particles lose some energy during collisions/but amt is very small

3. Thermal energy
Thermal energy is the total amt of a material’s particles including kinetic and potential energy
When temp is lowered, particles will have less thermal energy and vibrate more slowly

4. Average Kinetic Energy
Temperature means the average kinetic energy in the substance OR how fast particles are moving
Book examples—pg. 489
SOLID STATE:
Solids—contain particles that are closely packed together
-have a specific shape/arrangement
*particles don’t slide past each other

5. Liquid State:
Liquids: have more kinetic energy than solids/particles slip by ea/other—flow
-Have definite volume
Melting point—temp at which a solid begins to liquefy
Heat of fusion—amt of energy needed to change from solid to liquid phase

6. Gas State:
Gases: take the shape of their container/no fixed volume or shape
Vaporization occurs by: evaporation and boiling
Boiling Point: the temperature at which pressure of the vapor in the liquid equals outside pressure
Heat of vaporization: amt of energy required for a liquid to change to a gas

7. Plasma State:
Diffusion—spreading of particles throughout a given volume until uniformly distributed
Occurs most rapidly in gases
Plasma—matter consisting of positively and negatively charged particles w/neutral charge
ex: sun, stars, lightning bolts, auroras

8. Thermal Expansion
Thermal expansion—an increase in size of a substance when the temp is increased
Expansion in Liquids/Gases
Ex: thermometer/hot air balloons
Typically gases expand most with heat, then liquids, then solids

9. Evaporation: changing from liquid to a gas (as a liquid is heated)
Condensation: when water vapor in air cools and returns to liquid state
Sublimation: when liquids change from the solid state to the gaseous state (skips melting)

10. Strange Behavior of Water
Water molecules have highly positive and highly negative areas
These charged regions affect the behavior of water
As temp drops/particles move closer together
Empty spaces form in ice and are larger than in liquid water
So: water expands when going from liquid to solid state

11. Amorphous Solids and Liquid Crystals
Amorphous solids—do not have a definite temp at which they change from solid to liquid, but change gradually over a temp range
Ex: plastics and glass
Liquid crystals:
start to flow during the melting phase similar to a liquid, but do not lose their ordered arrangement completely
ex: LCD-watches, calc’s, etc.

12. SECTION 2: Properties of Fluids
Buoyancy: the ability of a fluid to exert an upward force on an object immersed in it
IF buoyant force = object’s weight, then object FLOATS
IF buoyant force < object’s weight, object will SINK

13. Archimedes’ Principle
Archimedes found that the buoyant force on an object = weight of fluid displaced by object
Ex: pg. 497/498
Density = mass / volume
An object will float if its density is less than the density of the fluid it is placed in

14. Pascal’s Principle Pressure = force /area
Pascal’s Principle: pressure applied to a fluid is transmitted throughout the fluid
Ex: hydraulic machines—raising cars on hydraulics

15. Bernoulli’s Principle
-as the velocity of a fluid increases, the pressure exerted by the fluid decreases
**paper ex: pg. 500
Fluid Flow:
Viscosity—a resistance to flow by a fluid
-fluids vary in their tendency to flow because their structures differ

16. SECTION 3: Behavior of Gases
Pressure:
= force / area
Is measured in Pascals
Particle collisions create pressure and keep objects inflated by pushing the walls of the container outward
The more collisions, the more the walls of the container will expand and pressure increases
ex: balloons

17. VISCOSITY
When you heat a liquid, the viscosity of the liquid DECREASES
When you cool a liquid, the viscosity of the liquid INCREASES
(think syrup in the fridge, vs. syrup in the microwave)

18. Boyle’s Law Boyle’s Law:
If you decrease the volume of a container of gas and hold the temp constant, the pressure of the gas will increase
An increase in the volume of the container causes the pressure to drop, if the temp remains constant
ex: rubber /neoprene weather balloons—pg. 504

19. Pressure-Temperature Law
If the pressure becomes greater than the canister can hold, it will explode
CHARLES”S LAW:
the volume of a gas increases with increasing temperature as long as pressure does not change
As with Boyle’s law, the reverse is true also.