Describing Matter
Physical Property
– characteristic of a material that
you can observe without
changing the substance
Examples: color, size, shape,
density, melting point, boiling
point
Chemical Property
– characteristic of a
substance that indicates
whether it can undergo a
certain chemical change
Examples: flammable,
combustible, may react to
light
Physical Change
– a change in size, shape or state of matter; substance
DOES NOT change identity when it undergoes
physical change
Examples: melting ice,
cutting paper, breaking glass
Chemical Change
– a change in one substance to another substance
Examples: fireworks explode, rusting metal
The Law of Conservation of Mass
- Matter cannot be CREATED or Destroyed, it can
only change form.
States of Matter
Matter
– anything that has mass and takes up space.
Kinetic theory of Matter
– explains how particles in matter behave
 All matter is composed of particles
 Particles are in constant, random motion
 Particles collide with each other and walls of their container
STATE
SOLID
LIQUID
GAS
PLASMA
STATES OF MATTER
CHARACTERISTICS
PARTICLES
Definite shape and
Closely packed in
definite volume
geometric arrangement
Indefinite shape and
Have more space and
definite volume
slide pass each other
Indefinite shape and
Have energy to spread
indefinite volume
out evenly in container
High temperature
Positively and negatively
gas
charged
The state of a sample of matter depends on temperature
Temperature
Is the average kinetic energy of an object’s molecules
(how fast are they moving?)
- when the temperature increases, a substance will
EXPAND.
- Substances CONTRACT when cooled.
# Exception to Rule: Water when cooled it expands
Changes in State of Matter
Question:
Why is the grass wet in
the morning when it
didn’t rain the night
before?
CHANGES IN STATES OF MATTER
MELTING: FROM SOLID TO LIQUID
Melting
– change from a solid state to a liquid state
Melting point
– temperature at which a solid melts
FREEZING: FROM LIQUID TO SOLID
Freezing
– change from a liquid to a solid
state
Freezing point
– temperature at
which a liquid
freezes
VAPORIZATION: FROM LIQUID TO GAS
Vaporization
– change from a liquid to a gas
Boiling point
– temperature at which liquid begins to vaporize / change
to a gas.
Evaporation
– Occurs at the surface of liquid without heating liquid
directly (i.e. eventually a cup of water will evaporate if
left unattended)
CONDENSATION: FROM GAS TO LIQUID
Condensation
– change from a gas to a liquid state
Condensation point
– temperature at which a gas condenses or changes to a liquid.
ICE
FREEZING
CONDENSATION
WATER
CLOUD
Answer:
When temperature decreases at
night, gas molecules in the air
slow down and change phase
from a gas to a liquid (dew).