Question

If a gas with a volume of 12.5 L was cooled from 18 C to 0 C at constant pressure. What is the final volume

Answer 1

We can solve the problem by using Charle's law, which states that for a transformation of an ideal gas at constant pressure, the ratio between volume and absolute temperature of the gas remains constant:

`(V)/(T)=k`
where V is the volume of the gas and T its absolute temperature.

The previous law can be rewritten as

`(V_1)/(T_1)= (V_2)/(T_2)` (1)
Let's convert the initial and final temperatures of the gas in Kelvin:

`T_1=18C+273=291 K`

`T_2 = 0C+273 = 273 K`
and the intiial volume is

`V_1 = 12.5 L`

so if we re-arrange equation (1) and we use these data, we can find the final volume of the gas:

`V_2=V_1 (T_2)/(T_1)=(12.5 L) (273 K)/(291 K)=11.7 L`