Respuesta :

the molar mass is 16.0 grams 
To determine the molar mass of the unknown gas, we use Graham's Law of effusion which relates the rate of the gases with their respective molar masses. We calculate as follows:

r1 / r2 = √(M2 / M1 )

We let 1 represent the unknown gas and 2 the carbon dioxide.

r1 / r2 = 1.66 = √(44.01 / M1 )
M1  = 15.97 g/mol