1. Among various plastic hoses, silicone hose has the highest diffusion coefficient for diffusion of nitrogen gas, which is kept under pressure, through the walls. By using shell balance method, derive the concentration profile for diffusion process. Explain how the flux changes with respect to the plastic hose types that are given in the table below. (Boundary conditions:@r=R₁, CA= CA and @r-Ro, CA= CAO). Material Teflon Nylon 6 PVC Silicone DAB for N₂ gas (cm²/s) 1.25 0.00224 0.014 400

Helium gas is diffusing through a uniform tube 0.2 m long containing an equal amount of nitrogen gas at 298 K and constant pressure 1.00 atm. The partial pressure of helium gas at one end of the tube is 0.2 atm and 0.1 atm at the other end. The diffusivity of the gases is 0.703 x 10-4 m2/s. Calculate the diffusion flux of both helium and nitrogen at steady state. (R = 8.314 J K-1 mol-1 = 0.08206 L atm K-1 mol-1)