Answer:
The molar mass of B is 32.0 g/mol
The unknown gas might be O2 (option C)
Explanation:
Step 1: Data given
A sample of Xe takes 75 seconds to effuse out of a container.
An unknown gas takes 37 seconds to effuse out of the identical container
Molar mass Xe = 131.3 g/mol
Step 2:
Rate A / rate B = √ (MB/MA)
rate = amount / time
The equation includes rate, but you are given times. Since rate is amount/time, we have to invert that side of the equation.
Time B/Time A = √(MB/MA)
⇒with time B = the time the unknown gas needed to effuse = 37 seconds
⇒with time A = the time needed Xe needed to effuse = 75 seconds
⇒with MB = the molar mass of the unknown gas = TO BE DETERMINED
⇒ with MA = the molar mass of Xe = 131.3
37/75 = √ (MB/131.3)
MB = 32
The molar mass of B is 32.0 g/mol
The unknown gas might be O2
