# The States and Structure of Matter by liuqingyan

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```									Energy and States of Matter

Unit 1
Physical Science HS Credit
Mrs. Rubel
The States of Matter

• States of matter are the physical forms in
which a substance can exist:
Solid (crystalline and amorphous)
Liquids (with surface tension and viscosity)
Gas (pressure, Boyle’s Law and Charles's
Law)
Plasma (conductivity)
Solids
• When matter has a definite shape and
volume. The particles are so close
together that the atoms or molecules
move, but not fast enough to overcome
the gravitational attraction between
them. Each particle is locked into place
by the particles around it.
2 Types of Solids
• Crystalline solids – atoms/molecules
are arranged in repeating pattern of
rows. Ex: diamonds, ice and iron.

• Amorphous solids –atoms/molecules
are not in a particular order or
organized pattern. Ex: wax, rubber.
Liquids
• Liquids take the shape of the container
they are in. The atoms can move fast
enough to overcome the attraction
between them. The volume remains the
same, regardless of the container.
Buoyancy
• The ability of a fluid to exert an upward
force on an object immersed in it.
• If the buoyant force is equal to the object’s
weight, then the object will float.
• If the buoyant force is less than the
object’s weight, then the object will sink.
Archimedes’ Principle
• Archimedes and the Volume of Gold

• Object will sink until the weight of the
water displaced equals the weight of the
object.
How does a steel ship float?
• Bottom portion of the ship will sink until the
weight of the ship and the buoyancy of the
water are balanced. This is possible
because of the compartments of air.
• Titanic vs. iceberg (guess who wins?)
Pascal and Hydraulics
Pressure = force per unit area
F
P A

Pascal’s Principle states that pressure applied to a
fluid is transmitted throughout the fluid (ex:
hydraulics)
• Hydraulics: when liquids in a container are pressed,
the liquids move outward, causing pressure. This
pressure can be a force that can do work.
Examples: dentist chair, car brakes.
Bernoulli’s Principle
Bernoulli realized that, as the velocity of a
fluid increases, the pressure exerted by
the fluid decreases.
Examples: chemical sprayers (see page
488), airplane wings
Liquid Properties
• Surface tension – the force that acts upon the
particles at the surface of a liquid, causing the liquid
to form spherical drops.

Viscosity – A liquid’s resistance to flow. The stronger
the attraction between a liquid’s particles, the more
viscous the liquid is. Example: Honey and motor oil
(yum!)
LCDs
• Liquid Crystals have characteristics of
both solids and liquids. They will begin to
melt at melting point, but they do not lose
their arrangements – they retain their
geometric order in specific directions.
• Because they respond to electromagnetic
fields, they can be used in the displays of
watches, calculators, etc.
Gases
• Gas – the matter can change both shape and
volume. The atoms/molecules move so fast they can
break away from the attraction from each other. As
gases expand, there is actually empty space
between particles.

• Pressure – The amount of force exerted on a given
area. The more gas you have in a given area, the
more the crowded particles collide with each other at
a faster rate.
Gases Fill Their Containers
• When the attractive forces between
particles is overcome, then the
movement/collision between particles will
cause diffusion. Diffusion is the spreading
of particles throughout a given volume
until they are uniformly distributed.
Diffusion can occur in solids and liquids,
but most rapidly in gases.
Gas Laws
(think pressure and volume)
• Boyle’s Law – For a fixed amount of gas at a
constant temperature, the volume of this gas
increases as it’s pressure decreases.

Example: Balloons. If you squeeze a balloon, you are
applying pressure to the gas inside. The particles of gas
are forced to move close together. If you let go and
release pressure, than the gas expands in volume.
How Boyle’s Law Works
Boyle’s Law and Weather
Balloons
• When meteorologists release weather
balloons, they only put a small volume of
gas in each balloon. The balloon will
travel to the upper layers of our
atmosphere to get the information, where
the air is thin.
• Partner share: How does this apply to
Boyle’s Law?
Boyle’s Law
• A balloon has a volume of 8.0 L at a pressure of 90
kPa. What will be the new volume is the pressure
drops to 40.0 kPa?

Boyle’s Formula = P1V1 = P2V2
• P1 = 90.0 kPA          V1 = 8.0
• P2 = 40.0 kPA          V2 = ? So…

P1V1             (90.0 kPa) (8.0 L)
•    V2 =      P2      V2 =      40.0 kPa     = 18 L
Charles Law
(think temperature and volume)
• For a fixed amount of gas at a constant pressure, the
volume of the gas increases as its temperature
increases. The volume of gas will decrease as the
temperature decreases.
Why?
When the temperature increases, the particles of gas move faster
and expand as much as they can (increase volume). If it is
cooler, the particles slow down and do not expand
(decrease volume).
Charles’s Law
Using Charles’ Law
V1      V2
T1 =     T2 (Pressure must remain constant)
A 3.0 L balloon at 10.0oC was placed in a container of ice
water (2.0oC). What is the resulting volume?
V1 = 3.0L     T1 = 10 0oC
V2 = ?         T2 = 2.0oC
Charles’ Law
• Absolute Zero - Temp at which...
– the volume of a gas would equal zero.
– all particle motion would stop.

-273°C
or
0K
Last State of Matter: Plasma

• Plasma doesn’t have a definite shape or volume, and
the particles have broken apart.
• However, plasma has conductivity, which means that
an electric current can go through it. Electric and
magnetic fields can affect plasmas, but not gases.
• Natural plasmas are found in lightning, fire and in the
aurora borealis (Northern Lights).
• The artificial plasmas created in fluorescent lights are
created by passing electrical currents through the
gasses.
Artificial and Natural Plasma
Changes of State
• All changes of state are physical changes.
• The change requires a change in energy. If
energy is removed, then the particles move
slower (water to ice). If energy is added, then
the particles move faster (raising the
temperature).
• Heat, which is a transfer of energy, causes
temperature changes, which causes a change in
state.
The 4 Changes of State
1)Melting Solids to Liquids – the melting point
is the temperature when a solid becomes a
liquid. Melting point is a characteristic property
of a substance.
• Melting is an endothermic change, because
energy is absorbed by the substance as it
changes state. This energy increases the
motion of the molecules until they can overcome
their attractions to each other.
The 4 Changes of State
(continued)
2) Freezing Liquids to Solids- This is at
the substance’s freezing point.
Remember, you don’t loose energy (it
changes form)
Proof that freezing and melting points are
the same……
Heating Curve of a Liquid
When thermal energy (heat) is added, the
liquid begins to change state. The
freezing/melting points are equal, as are
the points for boiling/vaporization. At 0oC,
all energy is put into the ice to overcome
attractive forces of particles. At 100oC,
the water is using all energy for boiling or
vaporization. See the graph on page 480.
Ice Water: The energy added to 0oC will melt the ice, but
it was removed at the same temperature to freeze the
water! So why doesn’t the water freeze?
The 4 Changes of State
(continued)
3) Vaporization: Liquids to Gases
- boiling is vaporization that occurs when a
substance reaches its boiling point, which
- Evaporation – vaporization that occurs at
the surface of a liquid below it’s boiling
point. The particles at the surface move fast
enough to break away from the surrounding
particles, and thus become a gas.
Thermal Expansion
• Thermal expansion is an increase in the
size of a substance when the temperature
is increased.
• When the temperature of an object is
lowered, particles slow down. The
attraction between the particles increases,
so they move closer together.
Thermal Expansion and Density
• When heat is added and particles begin to
expand, then there is a increased distance
between the particles. This expansion
means a decrease in density.
• This is why air is heated in a hot air
balloon. The air inside the balloon is less
dense than the outside air, so the balloon
will rise.
Boiling Point and Pressure
• Question:
• You visit a friend in Denver, Colorado.
You are cooking pasta, and you notice that
it takes very little time for the water to boil.
It appears to boil much faster than it did in
Atlanta. There must be some
relationship between the higher altitude
and the boiling point of water.
What is it?
The 4 Changes of State
(continued)
4) Condensation – Gases to Liquids
The condensation point of a substance is the
temperature at which the gas becomes a liquid
and the same temperature as the boiling point at
a given pressure.
Example: at sea level the same temperature that
causes evaporation creates steam
(condensation). The energy is removed
(exothermic change) so that the molecules of the
evaporated gas cool enough to slow down and
clump together.
The “5th State”
Sublimation
Sublimation - when solids go directly into a
gas.
This can only occur when the atoms or
molecules must move from being very tightly
packed to being very spread apart (completely
overcoming the attraction). This also requires
energy (endothermic change).
Example: dry ice. Once heat energy is added,
it goes from a solid to a gas.

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