Methanol (ρ = 791 kg/m3 and M = 32 kg/kmol) is evaporated in a Stefan tube with a uniform...

Methanol (ρ = 791 kg/m3 and M = 32 kg/kmol) is evaporated in a Stefan tube with a uniform cross-sectional area of 0.8 cm2. Initially, the methanol surface was 10 cm from the top of the tube; and after a while, the methanol surface was 26 cm from the top of the tube. The methanol vapor pressure is 17 kPa, and the concentration of methanol is zero at the top of the tube. If the entire process was operated at 25°C and 1 atm. determine the evaporation rate of the methanol in kg/h. The mass diffusivity of methanol in air is DAB = 0.162 cm2/s.