chemistry
posted by marie .
A mixture of 8.95 g of Cl2 and 18.0 g of NO2 and an undetermined amount of SO2 occupies a volume of 22.4 liters at 760 mm Hg and 0 C. How many moles of SO2 are present?

Use PV = nRT and solve for n = total number of mols.
Then convert g Cl2 to mols and convert g NO2 to mols.
Total mols = mols NO2 + mols Cl2+ mols SO2 
What is the R for? What answer do you get? I come up with 62 but that is not right.

R is a constant. If you are using V in L and P in atmospheres, then R = 0.08206. No, 62 is not right. If you substitute correctly, you should find n = 1 for total mols.