1. States of Matter
Unit 3

2. Section 1: Matter and Energy
Objectives
Summarize the main points of the kinetic theory of matter.
Describe how temperature relates to kinetic energy.
Describe four common states of matter.
List the different changes of state, and describe how particles behave in each state.
State the laws of conservation of mass and energy, and explain how they apply to changes of state.

3. Kinetic Theory
All matter is made up of atoms and molecules that act like tiny particles.
These tiny particles are always in motion. The higher the temperature of a substance, the faster the particles are moving.
At the same temperature, heavier particles move slower than lighter particles.

4. States of Matter Solid - definite shape and definite volume
Liquid - definite volume, changing shape
Gas - changing shape, changing volume
Plasma - changing shape, changing volume

5. Solids
Crystalline solids - have an orderly arrangement of atoms or molecules. Examples: ice, concrete.
Amorphous solids - composed of atoms or molecules that have no orderly arrangement. Examples: rubber, wax.
The particles in solids are held closely together by strong bonds, but they do vibrate constantly.

6. Liquids
The particles in a liquid move more quickly than those of a solid, which allows them to move freely.
Viscous liquid - liquid that does not change shape readily. Examples: honey, tar.
Surface tension - the force acting on the particles at the surface of a liquid that cause it to form round drops.

7. Gases Gases move more quickly than the other two states of matter.
Since gas expands to fill a space, it has no definite shape or volume. If you put a set amount of gas in a small container and release it into an enclosed room, it will spread out to fill the room.

8. Plasma
The most common phase of matter in the universe, making up 99% of known matter in the universe, though not on Earth.
The particles have broken apart, which causes plasma to be very unstable.
Plasma can conduct electricity and magnetism.
Found in lightning, fire, and the aurora borealis (northern and southern lights).

9. Temperature
Temperature is a measurement of how much kinetic energy a substance has.
The higher the kinetic energy, the higher the temperature of that object, so the hotter it is.

10. Energy Energy is involved in changes of state.
Evaporation (liquid to gas), melting (solid to liquid), and sublimation (solid to gas) all require energy to be added, making it warmer. This is an endothermic reaction.
Freezing (liquid to solid) and condensation (gas to liquid) require energy to be removed from the substance, making it cooler. This is an exothermic reaction.

11. Conservation of Mass and Energy
The Law of Conservation of Mass says that matter cannot be created or destroyed - it must come from pre-existing matter or it must be converted to another form of matter.
The Law of Conservation of Energy says that energy cannot be created or destroyed - it must come from a different source and must be converted to another form.

12. Section 2: Fluids Objectives
Describe the buoyant force and explain how it keeps objects afloat.
Define Archimedes’ principle.
Explain the role of density in an object’s ability to float.
State and apply Pascal’s principle.
State and apply Bernoulli’s principle.

13. Buoyant Force The upward force that fluids exert of matter.
This is what enables objects to float - the water is pushing them up. This only applies to objects that are less dense than water.

14. Archimedes’ Principle
Used to determine buoyant force.
The principle states that the buoyant force on an object in a fluid is an upward force equal to the weight of the fluid that the object displaces.
That means that an object only floats if the buoyant force on the object is equal to the object’s weight.

15. Fluids and Pressure
The pressure of a fluid is equal to the amount of force that is applied divided by the area of the object to which it is applied.
Or: pressure = force/area
Pressure is measured in units called pascals.

16. Pascal’s Principle
Pascal’s principle states that a change in pressure at any point in an enclosed fluid will be transmitted equally to all points of the fluid.
Or: pressure1 = pressure2 (p1=p2)
Hydraulic devices are based on this principle, and work by using liquids to transmit pressure from one point to another.

17. Bernoulli’s Principle
Used to describe fluids in motion.
States that as the speed of a moving fluid increases, the pressure of the moving fluid decreases.
This explains why putting your thumb over the end of a water hose causes pressure to build up, while uncovering the hose causes the water to slow down and come out more easily.

18. Section 3: Behavior of Gases
Objectives
Explain how gases differ from solids and liquids.
State and explain the following gas laws: Boyle’s Law, Charles’s Law, and Gay-Lussac’s Law.
Describe the relationship between gas pressure, temperature, and volume.

19. Properties of Gases Gas particles move in all directions.
Gases are fluids.
Gases have a very low density.
Gases are compressible and can be made to fit into a small container.
Gases mix easily with each other and are mostly empty space.
Gases exert pressure on their containers.

20. Boyle’s Law
States that for a fixed amount of gas at a constant temperature, the volume of a gas increases as its pressure decreases.
Also, if the pressure increases, the volume decreases.
Or: p1v1=p2v2
An inverse relationship: if p1 is high, v1 will be low.

21. Charles’s Law
States that for a fixed amount of gas at a constant pressure, the volume of the gas increases as its temperature increases.
Also, if the temperature decreases, the volume decreases.
A direct relationship: if t is high, so is v.

22. Gay-Lussac’s Law
States that the pressure of a gas increases as the temperature increases if the volume does not change.
So, if a pressurized container holding a gas is heated, it may explode!