Question

A pressure vessel is lined with a membrane to reduce the loss of helium. The membrane is made of a material through which the diffusivity of helium at 25 C is 3.091 x 10-10 m2/s. The concentration at the inner surface is maintained constant at 4.00 x 10-6 kg/m3. The concentration at the outer surface of the membrane is maintained constant at 2.00 x 10-6 kg/m3. The membrane thickness is 3.091 x 10-6 m and its area is 2.50 m2. How much helium escapes per hour through the membrane? Express your answer in kg.

Answer 1

1.8e-6