Chem 2 Diffusion Lab

Question

Methane gas diffuses from a container in 37 seconds. a second alkane diffuses from the container in 78.5 seconds. what is the mass and identity of the second alkane? (Hint: the distance traveled is the same for each gas)

Answer 1

Rate gas1/rate gas1 = sqrt MWgas2/sqrt MW gas1

methane = gas1

Rate is distance/time, assume distance is 1 meter

rate1 = 1/37 = 0.027

rate2 = 1/78.5 = 0.0127

MW1 = 16

MW2 = ?

0.027/0.0127 = sqrt x/sqrt 16

2.13 = sqrt x/4

sqrt x = 8.5

x =72.3 = mass of gas2

Identity of alkane could be isopentane (methylbutane)