posted by Sara .
A gas mixture containing N2 and O2 was kept inside a 2 L container at a temperature of 23 C and a total pressure of 1 atm. The partial pressure of oxygen was .722 atm. How many grams of nitrogen were present in the gas mixture?
Ptotal = pN2 + pO2
You know pO2, solve for pN2.
Substitute pN2 into PV = nRT and solve for n. Then
n = mols = grams/molar mass.
You know mols and molar mass; solve for grams N2.