Solid Liquid Gas
Volume Definite Definite indefinite
Particles Vibrate in
13.1 The Nature of Gases
• The word kinetic refers to
• The energy an object has
because of motion is
called kinetic energy.
• 1. The particles in a gas are
considered to be small, hard
spheres with an insignificant
• 2. The motion of the particles in
a gas is rapid, constant and
• 3. All collision between particles
in a gas are perfectly elastic.
• Particles are far apart.
• Between the particles there
is empty space.
• Motion is independent.
• No attractive or repulsive
forces are present.
Gases fill their container
regardless of their shape.
• Uncontained gases can
spread without limit.
• Particles only change
direction when rebounding
• Particles move at random.
Kinetic energy is
loss from one particle
•Total kinetic energy
• Gas pressure results from the force
exerted by a gas per unit surface area of
• Gas pressure is a result of simultaneous
collisions of billions of rapidly moving
particles in a gas with an object.
• An empty space with no particles and no
pressure is called a vacuum.
• Atmospheric pressure results from the
collisions of atoms and molecules in the air
• A barometer is device that is used to
measure atmospheric pressure.
MATH MONKEY MOMENT
1 atm=760 mm Hg= 101.3
Practicek cPoanverting units
What pressure, in
kilopascals and in
atmospheres, does a gas
exert at 385 mm Hg?
The pressure at the top of
Mount Everest is 33.7 kPa.
Is that pressure greater or
less than .25 atm?
Can you convert easily? Or did I just pull your tail 1. 51.3 kPa, .507
atm 2. 33.7 kPa is greater than .25 atm.
• Kinetic energy
• Gas pressure
SUM IT UP- What’s
happening in this clip on
the next slide?
Kinetic Energy and
• As a substance is heated, its particles
• Some gets stored in the particles as
• The rest of the energy speeds up the
particles thus increasing their kinetic
• Average kinetic energy is the
measurement of kinetic energy for a
substance regardless of physical state.
Kinetic Energy and
• Absolute zero is the theoretical point
at which all motion stops and kinetic
energy is zero.
• It has never been produced in a
laboratory but scientists have come
close in a vacuum.
• The Kelvin temperature of a
substance is directly proportional to
the average kinetic energy of the
particles of the substance.
13.2 The Nature of Liquids
• Particles in liquids have kinetic energy
like a gas.
• Substances that flow are referred to as
• The key difference between liquids and
gases, is that liquids have attractions
between the particles and gases don’t.
• The interplay between the disruptive
motions of particles in a liquid and the
attractions among the particles
determine the physical properties of
• The conversion of a liquid to a gas is
• When the conversion occurs at the
surface of a liquid that is not boiling, it is
• Most of the molecules in a liquid don’t
have enough kinetic energy to overcome
attractive forces and escape into a
• During evaporation, only those molecules
with a certain minimum kinetic energy
can escape the surface of the liquid.
• Vapor Pressure is a measure of the force
exerted by a gas above a liquid.
• Over time, the number of particles entering
the vapor increases and some of the
particles condense back into a liquid.
• In a system at constant vapor pressure, a
dynamic equilibrium exists between the
rate of evaporation and the rate of
• An increase in the temperature of the liquid
increases the vapor pressure.
• The rate of evaporation of a liquid from an
open container increases as the liquid is
• When a liquid is heated to a temperature
at which particles throughout the liquid
have enough kinetic energy to vaporize,
the liquid begins to boil.
• The temperature at which the vapor
pressure of the liquid is just equal to the
external pressure on the liquid is the
Vapor pressure less than
Vapor pressure more than
Boiling Point and Pressure
• Liquids don’t always boil at the same
temperature all the time.
• Change in altitude affects the boiling
• Higher altitudes decrease boiling
• Lower altitudes (under water)
increase boiling points.
• Normal boiling point is at standard
pressure of 101.3 kPa.
• Potential energy
• Average kinetic energy
• Vapor pressure
• Boiling point
POST IT UP
When will a liquid evaporate?
I GOT THIS!
I NEED HELP!
13.3 The Nature of Solids
• The general properties of solids reflect
the orderly arrangement of their particles
and the fixed locations of their particles.
• When you heat a solid, its particles
vibrate more rapidly as their kinetic
• The melting point is the temperature at
which a solid changes into a liquid.
• The melting and freezing points are at the
same temperatures and the solid and
liquid phases are in equilibrium.
• Some solid substances can exist in
more than one form.
• Allotropes are two or more different
molecular forms of the same
element in the same physical state.
• Carbon is one example.
• Carbon can exist as a diamond,
graphite and as fullerene.
13.4 Changes of State
• Sublimation occurs in solids with vapor
pressures that exceed atmospheric
pressure at or near room temperature.
• Examples are iodine and carbon dioxide.
• A phase diagram is a visual
representation of boiling, melting and
• The triple point is a point in which all three
states of matter exist at one time.
• Boiling and melting points vary with
• Research an allotrope of carbon.
• You may choose any type.
• Write a one page type I paper about
• Things you could include: examples,
pictures, experiments, history,
discoveries, past/present/future of
POST IT UP
What is the triple point?
I GOT THIS!
I NEED HELP!