- Victor Meyer apparatus
The Victor Meyer apparatus is the standard laboratory method for determining the
molecular weight of a volatileliquid . It was developed byViktor Meyer , who spelled his name "Victor" in publications at the time of its development.The apparatus consists of a vertical glass column contained in a steam jacket, with a small bed of sand in the bottom of the column to protect its glass base. A delivery tube leads from the top of the column to a
gas jar in ahydraulic trough . A small glass vial with aground glass stopper is at the top of the column, containing a weighed quantity of the liquid to be tested. The vial rests on a device called the "spoon", which can be rotated to release the vial.When the spoon is rotated, the vial drops to the bottom of the column. The liquid vaporises, ejecting the stopper from the vial and displacing a volume of air equal to the volume of the vaporised liquid at 100°C, the temperature being controlled by the presence of the two phases of water in the steam jacket. This air is collected in the gas jar, and its volume measured.
The molecular weight can then be calculated using the mass of the liquid sample and its volume as a gas at the temperature at which the air is collected (room temperature).
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