Describe the two methods for determing the volume of the vap

Describe the two methods for determing the volume of the vapor In a Molar Mass of a Volatile Liquid experiment? Which method is likely to give more precise results? Why?

Solution

PV = nRT
(pressure in atms, volume in L, moles, .0821, temperature in kelvins)

PV(mw) = mRT
(molecular weight in grams/mol, m in grams)

P(mw)=DRT
(Density in grams/Liter)

Dumas method will give you precise result method is as follows:

In the Dumas method a volatile liquid is heated to a known temperature (above its boiling point) and allowed to escape from a container through a tiny orifice. Once the liquid has vaporized, the container is cooled to room temperature. Gradually the vapor which remained in the container at the higher temperature condenses to a liquid and is then massed. If the volume of the container is known along with the high temperature, the room pressure can be used (because the system is open to the atmosphere through the orifice) to calculate moles. From there a molar mass can be determined