1. Temperature and Volume
General, Organic, and Biological Chemistry
Fourth Edition
Karen Timberlake
Chapter 7
Gases
7.4
Temperature and Volume
(Charles’ Law)
Lectures
© 2013 Pearson Education, Inc.

2. Charles’s Law Charles’s law states that,
the Kelvin temperature of a gas is directly related to the volume of the gas,
P and n are constant, and
as the temperature of a gas increases, the molecules move faster and its volume increases to maintain constant P. 2

3. Charles’s Law: V and T
Charles’s law states that when the temperature of a gas increases, making the molecules move faster, the volume of the gas must increase to maintain constant pressure. 3

4. Charles’s Law: V and T
A sample of neon gas has a volume of 3.1 L and a temperature of 12 ˚C. Find the new volume (L) of the gas if the temperature rises to 32 ˚C. Assume the pressure and amount of gas remain constant.
Step 1 Organize the data in a table of initial and
final conditions.
Analyze the Problem.
Conditions 1
Conditions 2
Know
Predict
T1 = 12 °C = 285
T1 = 32 °C+ 273
= 305 K
T increases
V1 = 3.1 L
V1 = ?
V increases 4

5. Charles’s Law: V and T
A sample of neon gas has a volume of 3.1 L and a temperature of 12 ˚C. Find the new volume (L) of the gas if the temperature rises to 32 ˚C. Assume the pressure and amount of gas remain constant.
Step 2 Rearrange the gas law equation to solve
for the unknown quantity. 5

6. Charles’s Law: V and T
A sample of neon gas has a volume of 3.1 L and a temperature of 12 ˚C. Find the new volume (L) of the gas if the temperature rises to 32 ˚C. Assume the pressure and amount of gas remain constant.
Step 3 Substitute values into the gas law equation
and the table. 6

7. Learning Check A balloon has a volume of 785 mL at 21 ˚C. If the
temperature drops to 0 ˚C, what is the new volume of the balloon (P constant)? 7

8. Solution
A balloon has a volume of 785 mL at 21 ˚C. If the temperature drops to 0 ˚C, what is the new volume of
the balloon (P constant)?
Step 1 Organize the data in a table of initial and final
conditions.
Analyze the Problem.
Conditions 1
Conditions 2
Know
Predict
V1 = 785 mL
V2 = ?
V decreases
T1 = 21 °C = 294 K
T2 = 0 °C = 273 K
T decreases 8

9. Solution
A balloon has a volume of 785 mL at 21 ˚C. If the temperature drops to 0 ˚C, what is the new volume of
the balloon (P constant)?
Step 2 Rearrange the gas law equation to solve for
the unknown quantity.
Step 3 Substitute values into the gas law equation and the table. 9