Question

127 ml of a gas at 136°C and 758 mm pressure
weigh 0.4524 g. If 1 mL of hydrogen at S.T.P.
weighs 0.00009 g, calculate the vapour density and
molecular mass of the gas. [Ans. 59.45, 118.90​

Answer 1

Explanation:

volume=380 ml=0.380 liters

temperature= 270c=273+27=300K

Now, using by formula 

PV=nRT  (R= gas constant= 8.2×102

n=RTpv=8.2×102×3001.052×0.380=0.0162

Now, given mass of the gass is 0.455

no of moles= molarmassmass

molar mass=noofmolesmass

0.01620.455=28.08g/mole