posted by Ashley .
A gas mixture with a total pressure of 770 contains each of the following gases at the indicated partial pressures: CO2 , 249mmHg ; , Ar 114mmHg ; and , O2 174mmHg . The mixture also contains helium gas.
1. What is the partial pressure of the helium gas?
2. What mass of helium gas is present in a 11.2 L sample of this mixture at 281 K?
Ptotal = PCO2 + PAr + PO2 + PHe.
Only 1 unknown; i.e., PHe.
2. I would use PV = nRT, solve for n = number of moles He, then moles = grams/molar mass will solve for grams.
Post your work if you get stuck.