Can you help me with this Grahm's Law AP Chemistry Problem?

Question

The rate of effusion of a particular gas is 24.0 L/min. Under the same conditions, the rate of effusion of CH4 is 47.8 L/min. What is the molar mass of the unknown gas?

Answer 1

Graham's Law of Effusion: rate of effusion is inversely proportional to the square root of the molar mass

rate gas1/rate gas2 = √MW gas2/√MW gas1

rate CH4 = 47.8 L/min

MW CH4 = 16 g;mole

rate X = 24.0 L/min

MW X = x

47.8/24.0 = √x/√16

1.99 = √x/4

√x = 7.97

x = 63.5 = molar mass of unknown gas