3. Methane gas is diffusing in a straight tube 0.1m long containing helium at 298 K and a total pressure of 1.01325105Pa. The concentration of CH4 at one end is 13.816 mole \% and 1.316 mole \% at the other end. Helium is insoluble in one boundary, and hence is non-diffusing or stagnant. Calculate the flux of methane in kg mole/s. m2 at steady-state