An evacuated glass vessel weighs `50.0 g` when empty, `148.0 g` when filled with a liquid of density `0.98 g mL^(-1)`, and `50.5 g` when filled with an ideal gas at `760 mm Hg` at `300 K`. Determine the molar mass of the gas.

Explanation

`"Weight of liquid "=148-50=98g`
`"Density of liquid "="0.98 g ml"^(-1)`
`therefore" Volume of liquid "=(98)/(0.98)="100 ml"`
`"Wt. of gas"=50.5-50.0=0.5g`
`"Volume"=(100)/(1000)L,P="1 atm,"T=300K`
`pV=nRT or pV=(W)/(M)RT`
`(1xx100)/(1000)=(0.5)/(M)xx0.082xx300`
`therefore" "M="123.15 g mol"^(-1)`.