Transcript Lesson 2

CST Review Session 2
-Solids, Liquids, Gases
-Phase Changes
-Boiling/Condensation and
Melting/Freezing Points
There are THREE states of matter:
State
Packing of
Particles
Movement of
Particles
Energy
Possessed by
Particles
Solids
Particles
packed close
to one another.
Particles
vibrate in
place; locked
in position.
Little KE
possessed by
particles.
Liquid
Particles
packed close
to one another.
Particles are
more loosely
arranged; can
roll over one
another.
More KE
possessed;
Liquid
particles can
flow.
Gas
Most
disorderly
state; particles
far apart from
each other;
have little
attraction for
one another.
Gas particles
dart about,
colliding with
each other and
with walls of
container.
Gas particles
possess the
most KE.
b
Application or Removal of HEAT ENERGY
converts matter from one state to another.
1. Which state is characterized by particles
that can only vibrate in place?
2. Which state is characterized by particles
able to move freely and possess the most
amount of KE?
3. Which state is characterized by particles
that can slip and slide over one another but
are still close to each other?
Checkpoint
4. Is this a solid, liquid or gas?
5. Is this a solid, liquid or gas?
6. Is this a solid, liquid or gas?
Addition of Heatcauses
particles to move faster.
MELTING: heat is added to make ice
melt into a liquid.
EVAPORATION: When
heat is applied to
liquid water, some
molecules “escape” to
become a gas.
Melting
SOLID
Evaporation
LIQUID
Melting Point
Adding heat changes a solid
to a liquid, and a liquid to a
gas.
GAS
Boiling Point
• By doing this, a gas
changes to a liquid!
Removing HEAT!
• Or change a liquid to
a solid!
Freezing
SOLID
Freezing Point
Condensation
LIQUID
GAS
Condensation Point
Water vapor
condenses
[becomes dew] on
leaves when it
gets cold
(condensation).
When it’s very
cold, snow forms
(freezing).
All changes in state are just PHYSICAL
CHANGES- the composition and
identity of the substances are NOT
changed.
Q. Substance X melts at 40oC and
boils at 125oC. At what state will it be
at the following temperature?
a. 100oC?
SOLID
B. 17oC?
LIQUID
Melting Point
GAS
Boiling Point