2.  Change of State:
 Change of a substance to one physical form to another
 Physical changes
 Identity of the substance does not change
 Ex: ice, liquid water, and steam are all the same
substance.
 State of matter is based on the amount of energy in
the substance
 to change the state of matter you add or take away energy.

Ice – little energy

Liquid water – moderate energy

Steam – a lot of energy

3. Examples of Physical
Properties
 Color, odor, hardness, density,
melting point, boiling point,
state, solubility.

4.  Melting:
 Change of state from a solid to liquid

Melting ice
 Adding energy increases temperature and causes the particles to
move faster.
 Melting Point:
 Temp. at which a substance changes from a solid to a liquid
 Different substances have different melting points
 Energy added to a solid is used to overcome the attraction
between particles
 Endothermic Change:
 Energy is gained by the substance as it changes state

5.  Freezing:
 Change of state from a liquid to a solid.
 Freezing Point:
 Temp. at which liquids turn to solids
 Attraction must overcome the motion of the
particles
 Removal of energy will cause the particles to
lock in place
 Exothermic Change:
 Removal of energy

6.  Evaporation:
 Change of a substance from a liquid to a gas
 Occurs at the surface of a liquid below the boiling
point
 Boiling:
 Change of a liquid to a gas throughout the liquid
 Occurs when the pressure inside the bubbles equals the
outside pressure
 Boiling point changes with atmospheric pressure

Lower the pressure lower the boiling point

7.  Condensation:
 Change of state from gas to liquid
 Condensation Point:
 Temp. at which a gas becomes a liquid
 Exothermic change
 Energy is removed and particles clump
together when the attraction between them
overcomes the motion

8.  Sublimation:
 A solid changes directly to a gas
 Endothermic change
 Energy is added and the particles move
quickly breaking the attraction between
them

9. Change of Phase
Melting solid  liquid
Condensation gas  liquid
Freezing liquid  solid
Evaporation liquid  gas
Sublimation solid  gas
Boiling: Evaporation occurring beneath the
liquid’s surface.

10. Change of Phase
Melting solid  liquid
Condensation gas  liquid
Freezing liquid  solid
Evaporation liquid  gas
Sublimation solid  gas
Boiling: Evaporation occurring beneath the
liquid’s surface.