#### Transcript Chapter 13

```Chapter 13
States of Matter
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States of Matter
matter classified as one of these physical
states
• solids,
• liquids and
• gases.
• 4th state of matter—plasma: does not occur
naturally on Earth except in the form of
lightning bolts.
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States of Matter
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States of Matter
• The physical state of a sub is a physical
property of that sub.
Other physical properties:
• m.p., b.p., heat conductivity, electricity
conductivity, color, crystal shapes, hardness
etc.
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Solids
A solid is a physical state
matter that has
 definite shape and
definite vol.
e.g.Wood, Fe,
paper, and sugar
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Solids
• particles tightly and
orderly packed.
• When heated, expands
slightly
• fixed position (particles
just vibrate)
• Definite shape
• Not conform to shape of
container
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Solid
Particle Movement
Examples
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Liquids
A liquid is a state of matter that flows (fluids)
 constant volume, and
takes the shape of its container.
e.g. liquids : H2O, blood, and Hg.
Particles
 not rigidly held in place
 less closely packed than those in a solid:
 able to move past each other.
 move much faster than (s)
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Liquids
 allows a (l) to flow
and take the shape of
its container
may not completely
filled the container
because definite
volume.
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Liquids
Because of the way
the particles of a (l) are
packed, (l) are virtually
incompressible.
Like (s), (l) tend to
expand when heated.
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Liquid
Particle Movement
Examples
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Gases
 A (g) is a state of matter that flows (fluid)
 to conform to the shape of its container and
fills the entire vol.
Particles
 very far apart (compressible)
 moving very fast (high KE)
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Gases
Gas: a sub that is naturally in
the gaseous state at room
temp.(oxygen gas)
Vapor:the gaseous state of a
sub that is a (s) or a (l) at
room temp. (water vapor)
e.g. steam is a vapor because at room temp
water exists as a (l). (steam is invisible)
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Gas
Particle Movement
Examples
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Gases
 subs can change physical states
 e.g. water changes to steam
 condensation:
 vaporization:
 evaporation:
 *melting—not involving gas
 sublimation:
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All vapor
All water (l)
vaporizing
water(l) temp
increasing
(e)
(d)
Temp increasing
(100°C)
All ice 0°C
(c)
Boiling water & vapor at
100°C
melting
All water(l) 0°C
(b)
(0°C)
Ice+water 0°C
(a)
Ice at
-60°C
(Ice) temp increasing
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Heating curve of water
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Kinetic Energy and Temperature
Absolute zero (0 K, or –273°C)
• temp at which the motion of particles
theoretically ceases.
• Particles would have no KE.
• Absolute zero has never been produced in the
lab. (on earth)
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Gases
Kinetic Theory for gases
The theory makes the
size, motion, and
energy of (g) particles.
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Kinetic Theory and a Model for Gases
kinetic → motion.
Kinetic Energy
 energy an object has because of its motion.
all matters (of different physical states) consist
of tiny particles that are in constant motion.
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Kinetic Theory for Gases
Assumptions for gases
(1)Particles in a (g) are separated by empty
spaces.
(2) vol of the empty space is much > than the
total vol of the (g) particles.
 total vol of particles ≈ 0.
(3) Since (g) particles are far apart and are so
light → inter-molecular attractive forces ≈ 0.
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Kinetic Theory for Gases
(4) (g) particles are in constant, random
motion in a straight line until they bump
into something (another particle or the side
of a container); only change direction;
continue to move …
(5) All collisions among particles in a (g) are
perfectly elastic.
An elastic collision
A collision in which KE is transferred w/o loss
from one particle to another.
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Particle Energy
Temperature
 a measure of the average KE of the particles
in a sample of matter.
• At higher temp
 gas particles absorbed heat energy
higher KE → move faster
 higher pressure (gases)??
• At a given temp, all (g) have the same average
KE.
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Particle Energy
The velocity of a particle includes
• both its speed and
• its direction.
Each particle in a sample containing only one (g)
will have the same mass but not the same velocity.
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Gas Pressure (1)
Gas pressure
When (g) particles collide with the walls of their
container, they exert pressure on the walls.
(pressure depends on the mass of (g) )
Pressure is force (N) per unit area (m2). --N/m2
Vacuum
An empty space with no (g) particles and no
pressure. (no collision)
Atmospheric pressure
pressure exerted by the particles in the atm
that surrounds Earth.
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Gas Pressure (5)
• The SI unit of pressure is the pascal (Pa).
• One standard atmosphere (atm) is the
pressure required to support 760 mm of Hg in
a Hg barometer at 25°C.
• Barometer …..
= 1 torr
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Gas Pressure (4)
A barometer is a device that is used to measure
atm pressure.
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Phase Changes that Require Energy (2)
vapor
• If a sub is usually a (l) at room temp (as water is),
the (g) phase.
Vaporization
• the process by which a (l)changes into a (g) or
vapor.
Evaporation
• vaporization occurs only at the surface of a (l)
at any temperature (not boiling)
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Phase Changes
• condensation ↔ vaporization
• sublimation↔ deposition
• freezing ↔ melting
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Fluidity
• Fluids: (l) and (g)
• Fluidity is the ability to flow.
• (l) are less fluid than (g).
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Liquid-vapor Equilibrium
Sealed container
evaporation
At Eqm,
Evaporation and condensation
equilibrium
Rate (l)→ (g) = rate (g)→ (l)
Evaporation rate = Condensation Rate
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Solids
Liquids
Gases
volume
Shape
density
Position of
particles
compressibility
Inter-molecular
attraction
Particle motion
Space between
particles
KE of particles
Arrangement of
particles
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melting↔freezing
Vaporization↔condensation
Sublimation↔deposition
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Phase Diagrams
Triple point
Critical point
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Phase Changes on phase diagram
Sublimation↔deposition
Melting (fusion)↔freezing
Vaporization↔condensation
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CST example 1
In a sealed bottle that is half full of water, eqm will be
attained when water molecules
A cease to evaporate.
B begin to condense.
C are = in # for both the (l) and the (g) phase.
D evaporate and condense at = rate
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CST problem 2
Under the same conditions of pressure and
temperature, a liquid differs from a gas because of
the molecules of the liquid
A have no regular arangement
B are in constant motion
C have stronger forces of attraction between
them.
D take the shape of the container they are in.
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CST problem 3
Methane (CH4) gas diffuses through air because the
molecules are
A moving randomly.
B dissolving quickly.
C traveling slowly.
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CST problem 4
When someone standing at one end of a large room opens a
bottle of vinegar, it may take several minutes for a person at
the other end to smell it. Gas molecules at room temperature
move at very high velocities, so what is responsible for the
delay in detection of the vinegar?
A
the increase in the airspace occupied by vinegar
molecules
B
the chemical rxn with nerves, which is slower than other
sensory process
C
attractive forces between the air and vinegar molecules
D
random collisions between the air and vinegar
molecules
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CST problem 5
If the attractive forces among (s) particles are less than the
attractive forces between the (s) and a (l), the (s) will
A probably form a new precipitate as its crystal
lattice is broken and re-formed.
B be unaffected because attractive forces
within the crystal lattice are too strong for the
dissolution to occur.
C begin the process of melting to form a (l).
D dissolve as particles are pulled away from
the crystal lattice by the (l) molecules.
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CST problem 6
The random molecular motion of a substance is
greatest when the substance is
A
B
C
D
condensed.
a liquid.
frozen
a gas
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CST problem 7
The boiling point of (l) nitrogen is 77 K. It is observed that
ice forms at the opening of a container of (l) nitrogen. The
BEST explanation for this observation is
A water at 0°C is colder than (l) nitrogen and
freezes.
B the nitrogen boils and then cools to form a (s) at
the opening of the container.
C water trapped in the (l) nitrogen escapes and
freezes.
D the water vapor in the air over the opening of the
(l) nitrogen freezes out.
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The End
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