Two methods were described for determining the volume of the flask used for the molar mass determination. Which method will give a more precise determination of the volume? Why?

Answer: DUMAS method which employs ideal gas law

Explanation:

the actual mass of the unknown vapor within the vessel can be calculated. Assuming the unknown compound obeyed the ideal gas equation, the number of moles of the unknown compound, n, can be determined by

pV=nRT

where the pressure, p, is the atmospheric pressure, V is the measured volume of the vessel, T is the absolute temperature of the boiling water bath, and R is the ideal gas constant. The number of moles can be obtained by dividing known mass by molar mass. And the volume can be obtained from the ideal gas formulae