VOLUME AND TEMPERATURE:
CHARLES’S LAW
13.1: Pgs. 450 - 454
Jacques Charles (1746-1823)



First person to fill a balloon with hydrogen gas
Made the first solo balloon flight
His main discovery is shown in the graph…
Plots of V (L) versus T (°C) for several gases.

Volume increases
when the
temperature
increases
 Direct
T
relationship, as
,V
Charles’s Law

Charles’s Law:
T
V1 V2

T1 T2
is in Kelvins
 CANNOT CHANGE the pressure or amount of gas
 It
tells us that the volume of the gas is directly proportional
to the temperature on the Kelvin scale
Plots of volume versus temperature

As we cool gases, they
eventually liquefy
 If
we extend a straight
line back, ALL lines
reach zero volume at 273 oC
 This suggests that
-273oC is the lowest
possible temperature
Absolute Zero and the Kelvin Scale

Lord Kelvin proposed a new temperature scale
based on this discovery
 Kelvin
(K) scale:
1
K same size as 1 degree C, but zero point changed to
-273oC and became 0 K (not degrees)
 260oC becomes ___ K?


13K
0 K is lowest temperature theoretically possible
 Absolute
 All
zero represents zero kinetic energy
motion stops theoretically
Example


A balloon inflated in a room at 24oC has a volume
of 4.00L. The balloon is then heated to a
temperature of 58oC. What is the new volume if
the pressure remains constant?
If a sample of gas occupies 6.80L at 325oC, what
will be its volume at 25oC if the pressure does not
change.
Gay-Lussac’s Law

Studies the relationship between pressure and
temperature

“The pressure of a gas is directly proportional to the
Kelvin temperature if the volume remains constant”
P1 P2

T1 T2
Example


The gas left in a used aerosol can is at a pressure
of 103 kPa at 25oC. If this can is thrown onto a
fire, what is the pressure of the gas when its
temperature reaches 928oC?
The pressure in an automobile tire is 198 kPa at
27.0oC. At the end of a trip on a hot sunny day, the
pressure has risen to 225 kPa. What is the
temperature of the air in the tire? (Assume the
volume has not changed.)