A tube of inner diameter 5 mm connects two chambers containing helium/argon gas mixtures of different compositions. The flowrates of each gas are measured and found to be: =2 mg/s and =4 mg/s (opposite signs imply opposite direction of flow). Compute the following:

The molar average velocity, , assuming that the pressure and temperature in the tube are uniform at =300 kPa and =350 K, and the gases are ideal