1. Temperature and Volume
Chapter 6 Gases
6.4
Temperature and Volume
(Charles’ Law)
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

2. Charles’ Law In Charles’ Law,
the Kelvin temperature of a gas is directly related to the volume.
P and n are constant.
when the temperature of a gas increases, its volume increases.

3. Charles’ Law: V and T For two conditions, Charles’ Law is written
V1 = V (P and n constant)
T T2
Rearranging Charles’ Law to solve for V2
T2 x V1 = V2 x T1
T T1
V2 = V1 x T2 T1

4. Learning Check
Solve Charles’ Law expression for T2.
V1 = V2
T T2

5. Solution V1 = V2 T1 T2 Cross multiply to give V1T2 = V2T1
Isolate T2 by dividing through by V1
V V1
T2 = T1 x V2 V1

6. Calculations Using Charles’ Law
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)?
1. Set up data table:
Conditions 1 Conditions 2
V1 = 785 mL V2 = ?
T1 = 21°C = 294 K T2 = 0°C = 273 K
Be sure to use the Kelvin (K) temperature in
gas calculations.

7. Calculations Using Charles’ Law (continued)
2. Solve Charles’ law for V2:
V1 = V2
T T2
V2 = V1 x T2 T1
V2 = 785 mL x K = 729 mL
294 K

8. Learning Check 1) 443°C 2) 170°C 3) - 82°C
A sample of oxygen gas has a volume of 420 mL at a temperature of 18°C. At what temperature (in °C) will the volume of the oxygen be 640 mL (P and n constant)?
1) 443°C
2) 170°C
3) °C

9. Solution 2) 170°C T2 = T1 x V2 V1 T2 = 291 K x 640 mL = 443 K 420 mL
= 443 K K = 170°C

10. Learning Check Use the gas laws to complete sentence with
1) increases 2) decreases.
A. Pressure _______, when V decreases.
B. When T decreases, V _______.
C. Pressure _______ when V changes from 12 L to 24 L
D. Volume _______when T changes from 15 °C to 45°C

11. Solution Use the gas laws to complete with 1) increases 2) decreases.
A. Pressure 1) Increases, when V decreases.
B. When T decreases, V 2) Decreases.
C. Pressure 2) Decreases when V changes from 12 L to 24 L
D. Volume 1) Increases when T changes from 15°C to 45°C