A 500 mL flask has a measured volume of 586.0 mL. A 0.608g sample of an unknown vapor occupies the flask at 373K at a pressure of 0.981atm. Assume the vapor behaves ideally. What is the molecular weight of the unknown vapor?

Answer 1

Use PV = nRT and solve for n = number of mols. Then n = grams/molar mass. You know mols and grams, solve for molar mass.