A container with a volume of 25 L contains a gas with a temperature of 150^o K. If the temperature of the gas changes to 120 ^o K without any change in pressure, what must the container's new volume be?

1 Answer
Dec 18, 2016

The new gas volume would have decreased to 20 L.

Explanation:

Apply Charles's law which states that the volume of an ideal gas is directly proportional to its absolute (Kelvin) temperature.

In equation form: V = k T

Your question requires that we write this in the form of a proportion

V_1/T_1 = V_2/T_2

(Note that these ratios are equal, because both would equal the constant, k.)

Now, we are ready:

V_1 and T_1 are the initial conditions - 25 L and 150 K.

T_2 is the new (changed) temperature - 120 K

25/150 = V_2/120

Solving for V_2, we get V_2 = (25 xx 120) / 150 = 20 L

A reduction in temperature has resulted in a reduction in volume.