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.