5.1.3 Charles's Law

Question 1

Charles’s Law

Answer 1

• Charles’s law states that for a given amount of gas at constant pressure, the volume is directly proportional to the temperature in kelvins.
• All gases theoretically go to zero volume at absolute zero(0 K).

Question 2

note

Answer 2

• Charles’s law states that for a given amount of gas at constant pressure, the volume is directly proportional to the temperature in kelvins. As the temperature increases, the volume increases.
• This can be stated mathematically as V T. Rearranging this expression yields V/T = constant.
• Since the volume divided by the temperature is constant, the volume divided by the temperature at an initial condition (Vi/Ti) will equal the volume divided by the temperature at a final condition (Vf/Tf). This relationship can be used to solve for Vi, Ti, Vf, or Tf, given the other three variables.
• All gases theoretically go to zero volume at a temperature of –273.15˚C. This temperature is referred to as absolute zero, and is the basis of the Kelvin temperature scale. On the Kelvin scale, absolute zero is 0 kelvins.

Question 3

For Charles’s Law to be true for gases which of the following parameters must remain constant?

Answer 3

the pressure and number of moles

Question 4

Predict what will happen to the volume of a gas if the gas is cooled, at constant pressure, from 75°C to 23°C.

Answer 4

the volume will decrease

Question 5

A sample of argon gas occupies 3.5 L at 90°C. At what temperature would it occupy 2.9 L if the pressure remained constant?

Answer 5

28 °C

Question 6

A sample of gas is at an initial volume of 2.7 L and a temperature of 45°C. If the gas volume increases to 4.2 L, what will its temperature be? You can assume that the pressure remains constant.

Answer 6

490 K

Question 7

A sample of helium gas is at 100°C. The helium is cooled to a temperature of 50°C and a volume of 2.95 L. What was the initial volume of the helium gas if the pressure is constant?

Answer 7

3.41 L

Question 8

At what temperature (Kelvin) would a gas have no volume at all?

Answer 8

0 K

Question 9

A sample of gas occupies a 6.2 L container at some initial temperature. As the gas is heated to 50°C, the volume expands to 9.5 L. What was the initial temperature of the gas?

Answer 9

210 K

Question 10

Predict what will happen to the temperature (in Kelvin) of a gas if the volume of the gas doubles at constant pressure.

Answer 10

The temperature will double.

Question 11

A sample of gas at 80°C is cooled by 30 degrees until its final volume is 1.75 L. If the pressure remains constant, what was the initial volume of the gas?

Answer 11

1.91 L

Question 12

According to Charles’s Law, what will happen to the temperature of a gas if the volume is decreased (while the gas remains at a constant pressure)?

Answer 12

The temperature will decrease.