CHARLES’ LAW
A gas in a closed system at a constant
pressure, the temperature and the
volume are directly proportional.
CHARLES’ LAW
• Directly proportional means that as the
temperature increases, the volume increases.
• Or as the temperature decreases the volume
decreases.
• Mathematically: V1
V2
T1
T2
CHARLES’ LAW
• The balloon in the
picture has a volume of
0.5 liters at a room
temperature of 22oC.
• What will the volume of
the balloon be if put
into some liquid
nitrogen?
• The liquid nitrogen is at
-196oC.
KELVIN
• Before doing anything, you must convert the
temperatures to the Kelvin scale.
• K = C +273
• K = 22 + 273 = 295 K
• K = -196 +273 = 77 K
• Now you can plug the numbers into the
Charles’ law equation.
The volume goes down, down, down!
0.5 L
295 K
V2_
77 K
Cross Multiply
295 V2 = 38.5
V2 = 0.13 liters
Practice Makes Perfect
• Practice Problem #1:
• A container with a
volume of 148ml is at
standard temperature.
If the container is
heated to 500 K, what is
the new volume?
• Standard Temperature:
0oC = 273 K
• Practice problem #2:
• A syringe is set at 7ml at
a temperature of 25oC.
If the volume is
increased to 9ml, what
is the new
temperature?
• Work these problems
on your paper and then
check your answer.
How did you do?
• Practice problem #1,
the answer is 271ml
• Practice problem #2,
the answer is 110oC.
(To get the correct
answer, you had to
convert 25oC to 298 K,
the answer is also 383K)
• Practice problem #3:
• A basketball is inflated
to 3.5 liters with an air
temperature of 40oC.
When the basketball is
taken outside, the
volume drops to 3.1
liters. What is the
temperature outside?
The answer is
o
4C
Now it is time to move on to
DALTON’S LAW
DALTON’S LAW
The sum of the partial
pressures is equal to the
total pressure.
DALTON’S LAW
• The two containers
have equal volume.
• The containers are
connected by a hose,
but the valve is closed.
DALTON’S LAW
• The container on the
left has a pressure of
500mm Hg.
• The container on the
right has a pressure of
300mm Hg
DALTON’S LAW
• If all of the gas from the
left container is pushed
into the right container,
what is the total
pressure of the gas?
• P1 + P2 + … = Ptotal
DALTON’S LAW
• The total pressure is
now 800 mmHg.
• The sum of the partial
pressures is equal to
the total pressure.
• Let’s try one practice
problem. 
P1 + P2 + … = Ptotal
• A 2 liter container has a gas with a pressure of
1.04 atm. Another 2 liter container has a gas
with a pressure of 760mm Hg. If the two
containers are combined into one 2 liter
container, what is the total pressure?
• Hint: Be consistent with units.
2.04 atm
• The easiest way to solve this problem is to
convert 760mm Hg to 1atm.
• From there, it is simple:
1.04atm + 1atm = 2.04atm