An oxygen gas is flowing through a 10m circular tube length with a radius of 16cm. Oxygen concentrations in the pipe ends are 30 kg/m^3 and 10 kg/m^3. The diffusion constant of the oxygen at 20 ° C is 1.8 x 10^-5 m^2/s. (a) Calculate the diffusion flow rate (b) How many kilograms of oxygen will flow through this tube in 15 minutes? (c) What is the oxygen concentration 2m away from the end of the tube where there is high concentration? (d) How long will it take 100 kg of oxygen to travel this tube?