1. Reference text: 14.1 page 413-417

2.  Solid
 Liquid
 Gas
 Which has a specific volume?
 Which has a specific shape?

3.  Compressibility – how much the volume of
matter decreases under pressure
 A gas can be squeezed into a small space
See the all the space
between the gas
particles? The particles
can be squeezed closer
together under pressure

4.  Pressure is the force the gas molecules exert
on the container as they collide with it
 Four variables to describe a gas:
 Pressure (P): measured in kilopascals (kPa)
 Volume (V): measured in liters (L)
 Temperature (T): measured in kelvins (K)
 Amount (n): measured in number of moles

5.  When you pump air into a container, you
 increase the amount of gas inside the tire,
 which increases the number of collisions between
gas particles,
 which increases the pressure
 Relationship is direct:
 If you double the amount of gas, the pressure
will double

6. Fewer gas particles,
lower pressure
More gas particles, higher
pressure

7.  In a sealed container, gases move from an
area of high pressure to low pressure

8.  If the volume of a container is reduced, the
pressure will increase

9.  If the volume of a container is increased, the
pressure will decrease
 Relationship is inverse
 If the volume is doubled, the pressure will
decrease by half

10.  If the temperature is increased, the particles
will move faster,
 Which causes more collisions between particles
 Which increases the pressure

11.  Increasing the temperature causes the
pressure to increase

12.  Decreasing the temperature will cause the pressure to
decrease
 Relationship is direct
 As the temperature is doubled, the pressure is doubled
 As the temperature is decreased by half, the pressure will
decrease by half

13. 1. Why is a gas easy to compress?
2. List three factors that can affect gas pressure.
3. Why does a collision with an air bag cause less damage
than a collision with a steering wheel? (extra help)
4. How does a decrease in temperature affect the pressure
of a contained gas?
5. If the temperature is constant, what change in volume
would cause the pressure of an enclosed gas to be
reduced to one quarter of its original volume?
6. What happens to particle motion as the temperature
increases? What if it decreases?
7. Write a paragraph explaining how the compressed gas in
an aerosol can force paint out of the can. Describe how
the gas pressure inside the can changes as the paint is
sprayed, and identify the variable that causes this
change. Refer to figure 14.5 in the text.