Charles’ Law
•volume
•temperature
Jacques Charles
Balloonist
1787 did
experiments
showing how
volume of gases
depends on
temperature
Relationship between V and T
Pressure & # moles are
constant
At high temperature,
gas particles move
faster & collide with
walls more often
•Pressure is constant,
so volume has to increase
Charles’ Law: Verbal
volume of gas at constant pressure
varies directly with its Kelvin temperature
Charles’ Law: Graphically
Plot V vs T (Kelvin)
Straight line that passes through zero
V=k
T
Charles’ Law: Problems
V1 = V2
T1
T2
Given any 3 variables, can find the 4th
Problem 1
150 mL of gas at constant pressure;
temperature increases from 20C to 40C.
What is the new volume?
Step 1: Convert T1 and T2 to Kelvin
Step 2: Rearrange equation:
V1 = V2 becomes V1T2 = V2
T1
T2
T1
Step 3: Substitute and solve:
(150 mL) (313 K)
= 160 mL
298K