# Chapter 10 – States of Matter by dffhrtcv3

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• pg 1
Chapter 10: States of Matter
• Kinetic Molecular Theory = the idea that
particles of matter are always in motion;
this applies to all states of matter
• Used to explain properties of matter in
terms of energy
Ideal Gases
= hypothetical gas that perfectly fits all 5 assumptions of
the KMT:

1) Gases consist of a large # of particles that occupy a
larger space with respect to their relative sizes thus
gases can be easily compressed
2) Collisions b/t particles and walls are perfectly elastic
( = no loss of KE)
3) Gas particles are in rapid, random, constant motion
4) There are no forces of attraction b/t gas particles
5) Temperature of a gas depends on the average
KE of the particles; directly proportional

A gas that is always a gas - Doesn’t exist!
The Kinetic Molecular Theory…
• Applies to only ideal gases
• Real gases act like ideal ones at low
pressure and high temperatures – explain!
Do Now
•   Homework: p. 336 and 341

1. What is the KMT?
2. What is an ideal gas? Real gas?
3. When do these two most resemble one
another?
4. What are some characteristics of a gas?
Characteristics of Gases
• Expansion: no definite shape or volume; fill any
container, regardless of shape
• Fluidity: particles slide easily over one another; act like
liquids, thus they are both fluids
• Low Density and Compressibility: volume can be
decreased
• Diffusion: since gases are always randomly moving,
freely mix together w/ other gases
• Effusion: process by which gases move out of a small
opening; molecules with low mass efuse more quickly
than those with larger masses

KE= ½ mv2
Polar gas molecules deviate from
ideal ones at times
• Explain…
• Also, real gases do not act like real ones
at low temps and high pressure – explain!
Liquids
• Least common state of
matter in universe; not so
on Earth
• Operate at slim range of
temps/pressures
• Volume, shape, density?
• Particles in constant
motion, and closer than
those of a gas (d/t
intermolecular forces
Other Characteristics of liquids:
• They have a very high density when
compared to gases; depends on
temperature  lower temp…
except for water
• Not easily compressed
• Easily diffuse in other liquids it can
dissolve in d/t… much slower than it is in
gases – why?
Surface Tension
• All liquids exhibit surface
tension = a force that tends to
liquids surface together,
decreasing its surface area to
the smallest possible size;
meniscus
• Results from… water shows
high surface tension
• Capillary action = attraction of
a liquid to a solid; rises in a
small tube against gravity
Surface Tension
Look at the picture below. The milk forms small droplets that
resemble a crown. But why does this happen?
Because of the surface tension of water, which keeps the
droplets spherical.
Do Now
1. What is the least common state of matter
in the universe? Why?
2. What happens to liquids as you
manipulate pressure and temperature?
What liquid tends to “disobey” the KMT
and normal behavior of liquids?
3. Why are ideal gases “ideal”?
Homework: SR on p. 348, 351, #35 on p.
354 (LL)
Some terms:
melting/freezing point             boiling/condensation point

0ºC                                             100ºC
solid                            liquid                             gas
MELTING                              BOILING

(ice)         FREEZING                           CONDENSING
(water)                           (steam)
• Vaporization – liquid
to gas
• Evaporation – escape
from a non-boiling
liquid at its surface
• Boiling – vaporization
through the entire
liquid
• Freezing – physical
change from liq.sol.
through the loss of
energy…
Solids
• Particles are tightly-
packed d/t attractive
forces  highly-ordered
• Motion is restricted, but
present
• 2 types:
1. crystalline = consists of
crystals (orderly,
geometric, repeating
pattern)
2. amorphous = particles
are randomly arranged
Properties of solids
•   Definite shape and volume
•   Definite melting point (d/t addition of heat)
•   High density and incompressible
•   Low rates of diffusion
Crystals
• Arranged in a lattice structure
• Smallest unit of a crystal that shows the 3-
D pattern of the lattice = UNIT CELL
Changes of State
• Phase = any part of a
system that has a
uniform composition
and properties
• Condensation =
process by which a
gas turns into a liquid
• Vapor = a gas in
contact with its liquid
or solid phase
Vapor Pressure
• The pressure exerted by a vapor that is in
equilibrium with its corresponding liquid
• Develops in a closed system
• Increase AKE, increase particles leaving
liquid, increased pressure
• Volatile liquids evaporate
easily d/t weak IMF
Notes on Boiling Point
• BP = when vapor pressure
equals atmospheric pressure
• Increase pressure, increase
BP = pressure cooker
• Molar Enthalpy of
Vaporization = amount of
heat needed to vaporize 1
mole of a liquid at the liquid’s
BP at a constant pressure; the
stronger the attraction….
• Vapor pressure is directly
proportional to temperature
• Vacuum evaporator – how
does it work?
Freezing and Melting
• Definitions?
• What is the difference b/t freezing water
and ice? Boiling water and steam?
Do Now
• Explain the importance and significance of
this graph…
More Vocab
• Molar heat of Fusion = the amount of
heat required to melt one mole of a solid
(symbol?)
• Sublimation vs. deposition
Phase Diagrams
graph of pressure vs. temperature that shows the conditions
under which the phases of a substance would exist
Water
• Most abundant liquid
on Earth; essential to
life; most reactions
take place in it
IMPORTANT!!!
• Review its structure
and properties…
Water

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