Answer:
The molar mass of the unknown gas is 128g/mol
Step-by-step explanation:
The rate of effusion of 2 different gases follows the equation:
Rate gas A / Rate gas B = √MM gas B / √MM gas A
Where rate is the speed of effusion of each gas and MM the molar mass of each gas
If gas A is oxygen and gas B the unknown:
Rate gas A / Rate gas B = 2 = √MM gas B / √32g/mol
11.134 = √MM gas B
128g/mol = MM gas B
The molar mass of the unknown gas is 128g/mol