Determination of Molecular Mass by Dumas’ Method
A gas will behave like an ideal gas under low pressure and high temperature ( p << pc and T >> Tc). As the gas tends to ideality, it is possible to apply the ideal gas law (pV = nRT) to calculate the molecular mass of an unknown gas (Mr = mass x RT/ pV). Where R is the gas constant 8.3143 m3·Pa·K-1·mol-1 and T is temperature in Kelvins
Warming up of the Dumas Bulb in a hot water bath
On cooling the bulb, the sample will be sucked into the bulb via the capillary.
Sealing of the Dumas Bulb after all the unknown liquid sample has been vaporised, with the Dumas Bulb still in the hot water bath.
Using of water to determine the vol of gas that occupied the Dumas Bulb.
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