240 mL of a dry gas measured at 27°C and 750 mm pressure weighed 0.64 g. What is the molecular mass of the gas ?

240 mL of a dry gas measured at 27°C and 750 mm pressure weighed 0.64

1.	240 mL of a dry gas measured at 27°C and 750 mm pressure weighed 0.64 g. What is the molecular mass of the gas ?
Answer» ANSWER :66.5