Two tanks are connected by a tube, 5 mm in diameter and 0.5 m long. One tank contains nitrogen and one tank contains carbon dioxide. The pressure and temperature are maintained at 200 kPa and 25 C. The diffusivity is 0.08 cm²/s. At some initial time, t=0, diffusion occurs between the two tanks. How long will it take for the mole fraction of the nitrogen to reach 0.7 on one end and 0.25 at the other end?

Determine at this time,

1.) the rates and directions of the mass transfer of carbon dioxide and nitrogen

2.) the velocities of each species

3.) the molar average velocity of the mixture