1. 3.2 Continued
Key Concept
How are the temperature, volume, and pressure of a gas related?

2. In 1787, the French scientist Jacques Charles discovered the relationship between the _______________ and ______________ of a gas at a constant pressure while doing work with hot air balloons
temperature
volume

3. When temperature decreases, gas particles will move ___________ and collide ________ often with the walls of their container….causing a balloon to _____________
When temperature increases, gas particles will move _____________ and collide more ______ with the walls of their container…causing a balloon to ____________
slower
less
shrink
faster
often
expand

4. So at a constant pressure, volume is ______________ proportional to temperature in ________________
directly
kelvins
So if temperature increases, what will happen to volume?
And if temperature decreases, what will happen to volume?
increase
decrease

5. The line on the graph is dashed as you move towards 0 K, also called ____________ ______, because volume can ____________ disappear and particles will
always move just
a _________ bit.
absolute
zero
never
tiny

6. Think carefully, can an item like a potato expand very much?
So why do you think people often poke holes in the skin of a potato before they heat it?
No!
To reduce pressure

7. Charles’s law only works for items that allow volume to __________ while keeping pressure constant
change

8. The equation for Charles’s law is…
V1=
V2 =
Hint….Charles is a television star V1 V2 = T2 T1
initial temperature
final temperature
initial volume
final volume

9. Practice!...If the temperature of a gas is doubled, what should happen to the volume of a gas?
If the temperature increases from 20 kelvin to 40 kelvin, what would the volume of 10 mL gas change to?
increase
40 K
10 mL x _________
20 K
= 20 mL

10. Boyle’s Law: Pressure and Volume
Robert _________ ( ), was the first to describe the relationship between the volume and pressure of a gas, at constant _____________
Boyle
temperature

11. number of gas particles changing?
Recall that adding pressure to a gas, similar to squeezing a balloon, can compress a confined gas into a _____________ volume
Is the actual amount or
number of gas particles
changing?
smaller
No!

12. According to the data shown, what happens to volume as pressure
increases?
Because the changes in pressure and volume are always _____________, their relationship is an ___________ proportion
Volume decreases
opposite
inverse

13. At a constant temperature, the pressure exerted by a gas depends on the ____________ of ______________ between gas particles and the container.
number
collisions
If the same number of ____________ are squeezed into a __________space, the frequency of collisions __________, thereby increasing the pressure.
particles
smaller
increases

14. Practice!...If the pressure of a gas is doubled, what should happen to the volume of a gas?
If the pressure increases from 1.0 atm to 2.0 atm, what would the volume of 10 mL gas change to?
decrease
1.0 atm
10 mL x _________
2.0 atm
= 5 mL

15. In mathematical terms, this law is expressed as follows.
Boyle’s Law
In mathematical terms, this law is expressed as follows.
P1 =
P2 =
V1=
V2 =
Initial pressure
Final pressure
Initial volume
Final volume

16. Vacuum Pump Demonstration
The vacuum pump will remove the air inside the glass chamber, _____________ pressure on the balloon
Predict what will happen to the size of the balloon. Were you correct?
Did the temperature of the room change during this demonstration?
reducing
Increased! no

17. The Combined Gas Law
The relationships described by Boyle’s law and Charles’s law can be described by a single law. The _______________ gas law describes the relationship among the temperature, volume, and pressure of a gas when the number of particles is constant.
combined

18. Assessment Questions
What causes the pressure to increase if more gas particles are added to a closed container?
an increase in the number of collisions between the gas and the container walls
a decrease in the volume of the container
a decrease in the size of each particle as the number of particles increases
an increase in the number of collisions between air particles and the outside of the container

19. Assessment Questions
When first blown up, a balloon is firm because of the air pressure inside it. However, after time, the balloon becomes soft as the air pressure inside drops. What could have caused the air pressure to decrease?
increase in air temperature
decrease in the balloon's volume
decrease in the number of air particles as they leaked out of the balloon
a chemical reaction between the air particles and the balloon

20. 3. According to Charles’s law, the relationship
Assessment Questions
3. According to Charles’s law, the relationship
between the temperature and the volume of a gas
is…
direct.
inverse.
exponential.
inverse square.

21. Assessment Questions
When the temperature of a gas in a closed
container is increased, the pressure increases. True False