A chemist conducts an experiment in which 2.00 L of hydrogen gas is collected over water at 1.00 atm and 298.15 K. Question

Question

Using the combined gas law, calculate the volume in L of the dry hydrogen gas at 273.15 K and a pressure of 1.00 atm.

Answer 1

The combined gas law can be written as :

P1V1/T1 = P2V2/T2

P1 = initial pressure = 1.00 atm

V1 = initial volume = 2.00 L

T1 = initial temperature = 298.15K

P2 = final pressure = 1.00 atm

V2 = final volume = ?

T2 = final temperature = 273.15K

Since no values are provided for the partial pressure of water vapor at the two different temperatures, it will be ignored in the following calculation.

(1.00)(2.00) / 298.15 = (1.00)(V2) / 273.15

V2 = (1.00)(2.00)(273.15) / (1.00)(298.15)

V2 = 1.83 L