# Problem: A gas mixture with a total pressure of 760 mmHg contains each of the following gases at the indicated partial pressures: 126 mmHg CO2, 220 mmHg Ar, and 188 mmHg O2. The mixture also contains helium gas.What mass of helium gas is present in a 12.6-L sample of this mixture at 274 K ?

###### FREE Expert Solution

Calculate the pressure of helium gas:

PHe = 226 mmHg

Calculate the pressure in atm:

1 atm = 760 mmHg

PHe = 0.2974 atm

Ideal Gas Law:

$\overline{)\mathbf{PV}\mathbf{=}\mathbf{nRT}}$

###### Problem Details

A gas mixture with a total pressure of 760 mmHg contains each of the following gases at the indicated partial pressures: 126 mmHg CO2, 220 mmHg Ar, and 188 mmHg O2. The mixture also contains helium gas.

What mass of helium gas is present in a 12.6-L sample of this mixture at 274 K ?