Q: What happens at high altitudes, like Denver &
Mt Everest? Below sea level altitudes?
•___________________
•Most space between molecules
•___________________
•Most compressible
Kinetic Molecular Theory:
________________________
________________________
________________________
________________________
• ____________: imaginary
gas that _____________
_______________of the
Kinetic Molecular Theory.
Fundamental assumptions of an Ideal Gas:
1.) __________________________________________________________
__________________________________________________________
Gas molecules are much further apart than in liquids & solids.
Most of a gas is empty space.
2. ) ___________________________________________________________
___________________________________________________________
3. ) Gas particle collisions are ________________
Elastic means: ____________________________________________.
Collisions are between gas particles, or against the container walls.
ALSO: The Average Kinetic Energy (KE ) of the gas depends on
Temperature (T).
___________________________________________________________________
___________________________________________________________________
Interested in the average KE because not all particles are moving at
the same speed, even though they are all at the same Temp.
Applications of Kinetic Theory of Gases.
1.) _____________: gases will always spread out
to fill any space they are in.
2.) Fluids (Gases & Liquids): gas particles can
move past each other without hindrance
(fluidity).
3.) Low Density: ______________________________
__________________________. therefore less
mass in the same volume
4.) Compressibility: ___________________because
of lots of empty space.
5.) Diffusion: _________________________________
______________________________________.
Pressure: ____________________________on a
surface. It is the result of collisions by gas
particles (Force) against any surface or
section of a container wall (Area),
Thus, _______________________________________
_________________ on the inside of the walls.
To decrease pressure you can increase the
area, lower the force
___________________________________________
_______________________, therefore we have
a gas pressure.
The atmosphere: the gases of the atmosphere
(N2 + O2 = 99%), exert pressure on the
Earth’s surface. This pressure value is known
as _______________________and:
Atmospheric Pressure = _____________
= _______________
= ____________(this is the
unit we will use)
Measuring pressure
Barometer: ______________________________
_______________________ (Early 1600’s by
Evangelista Torricelli)
Mercury: pushed down by gravity…
pushed up by atmospheric pressure until
it hits equilibrium… _______________
The pressure of the atmosphere
(101.3kPa) is enough to balance the
weight of Mercury (Hg) that is 76cm
high. ( = 29.9 in.)
_______________________________________
If the pressure of the atmosphere drops,
then it can’t support as much Hg, so
height level drops as well.
Because we know that pressure
depends on temp it is also clear that
the height of Hg  Temp.
Units:
The pressure of the standard atmosphere
(101.3kPa) has a special unit – atmospheres
(atm.)
______________________________________________
is also known as ___________________________
When giving details about
gases, __________________
_______________________.
The standard temperature
used is 0ºC (32oF)
So there is a __________
_________________________
(aka STP) and
STP = ___________________
Scott Weiland
(vocals) now of
Velvet Revolver
and his brothers in
Stone Temple Pilots
Diffuse
 ______________
Have Surface Tension
(we’ll come back to this)
 Form Solids


Evaporation: process in which liquid
molecules at the surface have enough KE to
leave (escape) and become gas molecules.
3 ways to speed up evaporation:
1) _______________________________________
2) _____________________
3) ______________________
Consider a closed
flask containing
some water at
room temperature
The ______________water molecules
at the surface leave and become a gas
- called ________________.
At the same time, some of the __________
___________________ molecules hit
the surface and become __________.
The ________________
____________________
___________________.
i.e. it adds its own Partial
Pressure to the air’s
pressure.
Eventually, the # of molecules turning into
vapor = # of molecules turning into liquid.
This is called _______________.
At equilibrium, ______________________
________________________________
________________________________
If you keep increasing the Temp., the vapor
pressure will increase until it equals the
atmospheric pressure.
At this temperature __________________
__________________________
This special Temp. is known as the _________
__________________
Now heat the liquid water. The KE of the
molecules increases, which means more
liquid molecules will become vapor.
The system reaches a new equilibrium
Liquid + Heat  Vapor
________________________________
As you cool the liquid the kinetic energy
decreases which means more of the molecules
become liquid
Liquid + Heat  Vapor
________________________________________________
___________________________________________
If you decrease the heat enough you will reach
the point where the liquid becomes solid…
_____________________________
Forming a Solid!
As Temp decreases, the
average KE also decreases
and we get :
Freezing: ________________
_________________________
_________________________
_____________(i.e. cooling)
•Least movement
•Least compressible
•Lowest Energy
Solids
The strong intermolecular forces hold the
particles of a solid in _____________
______________, with only vibrational
movement around fixed points, causing
the molecules to have an ordered
arrangement.
Crystalline solids: atoms
arranged in ________
_________________
_________________
Amorphous solids: atoms
_________________
e.g. glass, plastics,
wood…
Properties of Solids




Definite Shape and Volume
High Density; Low compressibility
Low Rate of Diffusion
Melting: physical change of a solid to a
liquid by adding heat . _______________
_________________________________
.
When substances form solids, at whatever Temp
that may be, they mostly form a ___________
___________________________________
___________________________________.