 with a flame), dried, and weighed.By subtracting the tare of the vessel, 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

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.