It rate of effusion of a particular gas was measured and found to be 24.0 ml/min. under identical conditions the rate of effusion of methane gas was measured and found to be 47.8 ml/min. what is the molar mass of the unknown gas?

The molar mass of unknown gas is 63.5 g/mol

calculation

let the unknown gas be represent by letter Y

The rate of effusion of a gas varies inversely with square root of molar mass

that is R (CH4) / R (Y) = √[ (M (Y) / M (CH4) ]

= 47.8 ml/min/24.0ml/min = √[ (Y/16g/mol) ]

square both side to remove square root sign

=47.8²ml/min / 24²ml/min = Y/16 g/mol

=2284.84ml/min/576ml/min=Y/16g/mol

multiply both side by 16

y = 63.5 g/mol