A tube contains air and methane gas was used in a standard diffusion rate determination experiment at 22 oC and 101.3 kpa. The partial pressure of methane was 30 x 10-4 atm at the end of the tube which was 78.2% lower at the other end. The tube radius was 0.042 m which is 7 times lower than its length.

Calculate.

1. The methane mass transfer rate.

2. The air's mass transfer rate.

3. The partial pressure of methane at the centre of the tube.

PS: State any assumptions clearly, if needed