Question

A volatile liquid sample is placed in an Erlenmeyer flask that has been sealed except for a tiny hole that allows vapor to escape. Upon heating, the liquid is converted to vapor that fills the flask. Cooling the flask allows the vapor to condense back to liquid. The mass of the condensed liquid is found to be 0.608g. The actual volume of the flask is 158.5 mL. The temperature of the flask contents is 32.4 degrees C and the atmospheric pressure reading is 30.52 inches of mercury. From this data determine the molecular weight of the volatile liquid.

Answer 1

PV = nRT. You have P (in inches which must be converted to atmospheres), you have V (convert to L), R and T(convert to kelvin). Solve for n = mols.
Then mols = grams/molar mass. You solve for molar mass.