A sample of air is made up of nitrogen, oxygen and argon in mole fractions 78% N2, 21% O2, 1.0% Ar, what is the density of air at STP?
What I did..
D = PM/RT where M is molar mass.
denisty of N2 using the above formula was: 1.25 g/l
denisty of O2 using the above formula was: 1.42 g/l
denisty of Ar using the above formula was: 1.74 g/l
so with mole fractions: (78 * 1.25) + (21 *1.42) + (1 * 1.74) = 129.01 g/l ( denisty of air)
is the process right? (ignore any incorrect rounding)