Chapter 3 – States of Matter
3.1 Solids, Liquids, and Gases

Solids
– Definite Shape
– Definite Volume
– Particles vibrate in fixed positions
– Particles have low kinetic energy

Liquids
– Variable shape (takes the shape of the
container)
– Definite Volume
– Particles can move around each other
– Particles have medium Kinetic Energy

Gases
– Variable shape
– Variable volume (fills all space in a container)
– Particles move about freely
– Particles have high Kinetic Energy

Plasma
– Exists only at extremely high temperatures
– 99% of the matter in the UNIVERSE is plasma
– Stars are plasma

Einstein-Bose Condensate
– Exists only at extremely low temperatures
– Groups of atoms behave as a single particle
Kinetic Theory
Kinetic energy = energy an object has
due to its motion
 The faster an object is moving; the
greater its kinetic energy.
 Kinetic theory states that all particles of
matter are in constant motion.

** View animation on visual concepts CD
3.2 The Gas Laws

Pressure = the result of force
distributed over an area
– More Collisions=More Pressure

In a closed container, gases exert
pressure when the particles of the gas
collide with the walls of the container.
Factors That Affect Gas Pressure

Temperature – raising temp. will increase
pressure if volume of gas and # of particles
are kept constant
– Inc. in temp.  part. move faster  part.
collide with walls more frequently  increased
pressure

Volume – Decreasing volume of a gas
causes an increase in pressure if the
temp. and # of part. are constant
– Decrease in vol.  less space  particles
collide with walls more often  inc. pressure

Number of particles – increasing the
number of particles of a gas will increase
pressure if temp. and volume are constant
– Inc. # of particles  particles collide with
container more often  inc. pressure
Gas Laws

Charles’ Law – volume of a gas is
DIRECTLY PROPORTIONAL to
temperature
– Inc. Temp. x2  Inc. Vol. x2
V1 =
T1
V2
T2

Boyle’s Law – volume of a gas is
INVERSELY PROPORTIONAL to pressure
– Inc. Vol. x2  Dec. pressure by ½
P1V1 = P2V2
Combined Gas Law
The Combined Gas Law – relates
temperature, volume and pressure of a
gas.
 Formula:

P1V1
T1
=
P2V2
T2
3.3 Phase Changes

Phase change – reversible physical
change that occurs when a substance
changes from one state of matter to
another
– Temperature of a substance DOES NOT
CHANGE during a phase change.
– Energy is either absorbed or released
during a phase change.


Endothermic – energy is absorbed
Exothermic – energy is released
Melting and Freezing

Melting
– Solid changes to liquid
– Particles absorb energy (endothermic)
– Particles become less orderly

Freezing
– Liquid changes to solid
– Particles release energy (exothermic)
– Particles become more orderly
Vaporization and
Condensation

Vaporization
– Liquid changes into a gas
– Particles absorb energy (endothermic)
– Particles become LESS orderly and more
free to move
– 2 types of vaporization


Evaporation – takes place at the surface of a
liquid
Boiling – occurs when a liquid is heated to its
boiling point

Condensation
– Gas changes to a liquid
– Particles release or lose energy (exothermic)
– Particles become MORE orderly
Sublimation and Deposition

Sublimation
– Changing from a solid
directly to a gas
– Energy is absorbed
(endothermic)

Deposition
– Changing from a gas directly to a solid
– Energy is released (exothermic)
Phase Change Diagram