A 239.4mg sample of a drug designed to treat malaria was run through a series of reactions to convert all the nitrogen in the compound into N 2 (g)....

A 239.4mg sample of a drug designed to treat malaria was run through a series of reactions to convert all the nitrogen in the compound into N2 (g). The gas collected over water at 23.8 oC and a pressure of 755.5 torr had a volume of 18.66 mL. The vapor pressure of water at this temperature is 22.11 torr.

a) Calculate the precent by mass of nitrogen in the sample. 

b) A 3.239mg sample of the drug is combusted in air to produce 8.785mg of CO2 (g) and 2.160 mg of water vapor. Determine the percent by mass of carbon and hydrogen in the sample. Assume that any remaining element is oxygen and calculate the empirical formula.

c) If the molar mass of the compound is 324.0g/mol, what is the actual molecular formula of the drug?