2.9 g of a gas at 95°C occupied the same volume as 0.184 g of dihydrogen at 17°C, at the same pressure. What is the molar mass of the gas?


From ideal gas equation we know that: -

PV = nRT


PV = m/M x RT



Where, P = pressure of dihydrogen


R = Universal gas constant


T= temperature of dihydrogen


m = mass of dihydrogen


M = molar mass of dihydrogen


V = volume of dihydrogen



Let M be the molar mass of the unknown gas, pressure remains constant. Volume (V) occupied by the unknown gas can be calculated in the same way as above:




According to the question,





= 40gmol-1


Hence, the molar mass of the gas is 40 g mol-1.


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