We are asked to calculate the molar mass of the unknown vapor.
m = 0.847 g
V = 355 cm3 = 0.355 L
P = 753 torr = 0.991 atm
T = 100 oC +273.15 = 373.15 K
R = 0.08206 L-atm/mol-K
The molar mass of a volatile substance was determined by the Dumas-bulb method. (In the Dumas-bulb technique for determining the molar mass of an unknown liquid, you vaporize the sample of a liquid that boils below 100oC in a boiling-water bath and determine the mass of vapor required to fill the bulb (see drawing ). The unknown vapor had a mass of 0.847 g, the volume of the bulb was 355 cm3, pressure was 753 torr, and temperature was 100 oC.
Calculate the molar mass of the unknown vapor.
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