posted by Rachel .
a flask with a volume of 267.5 mL contains a few milliliters of a volatile hydrocarbon. after vaporizing the gas at 100 degrees C, the flask is weighed and found to contain 0.728 grams of hydrocarbon vapor at 755 mmHg. a separate combustion analysis experiment revealed that the empirical formula osf the hydrocarbon was CH2. What is the molecular formula?