Diffusion coefficients for vapors in air are determined by measuring the rate of evaporation of a liquid in a vertical glass tube. For a 0.2 cm diameter tube filled with n-heptane at 21 C, calculate the rate of descent of the liquid level when the meniscus is 1 cm from the top, taking the diffusivity value of 0.071 cm 2 /s. At 21 C the vapor pressure and density of n-heptane are 0.050 atm and 0.66 g/cm 3 , respectively. , I need a solution explained and done by hand please, use mass transfer equations, make sure the units are correct and and please put the whole procedure