Chemisrty: A sample of an unknown liquid is vaporized in a flask.?

Question

The volume is 152.1 mL and open to the atmosphere through a pin hole. On a day when the atmospheric pressure is 756.2 torr, the sample is vaporized in an oil bath at 225.2 degrees C. The mass of the vapor is found to be 1.0050g. What is the gram molecular mass of the unknown liquid?

Answer 1

find moles:

PV=nRT

(756.2Torr)(0.1521Litres) = n (62.36Torr-L/mol-K)(498.35K)

n= 0.003701 moles

=================

molar mass:

1.0050 grams  / 0.003701 moles = 271.548 g/mol

your answer (4sigfigs) = 271.5g/mol