1. Solids, Liquids, and Gases
Mr. conkey Physical Science Chapter 3

2. Describing states of matter
Solid – a state of matter in which materials have a definite shape and a definite volume. Solids have some type of orderly arrangement of particles at the atomic level.
Liquid – a state of matter in which materials have a definite volume but not a definite shape. Atoms in liquids are close together but are more randomly arranged than those of a solid.
Gas – a state of matter in which material has neither a definite shape or volume. Gas takes the shape and volume of its container.

3. Bose-Einstein Condensate
Predicted by Albert Einstein that a fifth state of matter could exist at extremely low temperatures (near -273°C) where groups of atoms would behave as though they were a single particle. It was produced by scientists in

4. Kinetic Theory
Kinetic theory – the energy an object has due to its motion. All particles of matter are in constant motion.
The constant motion of particles in gas allows a gas to fill a container of any shape and size.
Not all particles move at the same speed; there are forces of attraction among particles in all matter.

5. Behavior of liquids and solids
Liquids take the shape of their container because particles in a liquid can flow to new locations. Volumes of liquids are constant due to forces of attraction keeping particles in liquids close together.
Solids have a definite volume and shape because particles in a solid vibrate around fixed locations. Strong attractions among atoms in solids restrict the particles motions and keep atoms in fixed locations so they can not change places with each other.

6. The Gas Laws: Pressure, Temperature, and Volume
Pressure is the result of a force distributed over an area. Collisions between particles of a gas and the walls of the container cause the pressure inside the container.
Pressure is measured in force (Newtons or N) and area (m²).

7. Factors that affect Gas pressure
Temperature
Volume
If the volume of a gas and the number of particles are constant, then raising the temperature will increase pressure. Lowering the temperature will decrease pressure.
These are directly proportional.
If the temperature of the gas and the number of particles are constant, then decreasing the volume of a gas increases the pressure. Increasing volume will decrease the pressure.
These are inversely proportional.

8. Factors that affect gas pressure (cont.)
Number of particles - if the temperature and volume are constant, then increasing the number of gas particles will increase the pressure.
Decreasing the number of particles will decrease the pressure of the gas (think collisions!).
These are also directly proportional.

9. The Gas Laws: Charles’ Law
0 K (Kelvin) is known as absolute zero (never achieved in a lab setting). The conversion from degrees Celsius to Kelvin is degrees C = K
Charles’ Law states volume and temperature of gas are directly proportional if pressure and # of particles is constant
The formula: V1/T1 = V2/T2

10. Boyle’s Law
Boyle’s law states that volume of gas is inversely proportional to its pressure if temperature and # of particles is constant
The formula: P1 X V1 = P2 X V2 (X = multiply)

11. The Combined Gas Law
Combines all the gas laws and relationships together
The formula: P1 X V1/ T1 = P2 X V2/ T2
Sample problem: A scuba diver starts with a tank of 5L of condensed air. The initial pressure is 300 kPa. The temperature before diving is 25 degrees C. She then dives down and the pressure goes up to 500 kPa and the temperature drops to 15 degrees C. What is the new volume in her tank?
Answer is 3L.

12. Phase Changes
Talk with your shoulder partner and try to come up with an idea of what you think a phase change is…

13. Phase changes (Cont.)
A phase change is the reversible physical change that occurs when a substance changes from one state of matter to another
Common phase changes include: evaporation, condensation, melting, freezing, sublimation, deposition, and vaporization
Key idea: The temperature of a substance does not change during a phase change

14. Phase Changes (Cont.)

15. Endothermic vs Exothermic
Energy is either absorbed or released during a phase change
When ice melts energy is absorbed which is an endothermic change
Endothermic – the system absorbs energy from it’s surroundings
When water freezes energy is release which is an exothermic change
Exothermic – the system releases energy to it’s surroundings
Endothermic or exothermic (a match, winter gloves, a refrigerator)?
Fridge is both exothermic and endothermic (condenser where energy is released, then evaporator where energy is removed from food compartment)

16. El Fin