Q1) In an air-carbon dioxide mixture at 25 °C and 3 atm, the concentration of carbon dioxide at two planes (2 mm) apart are 20 vol.% and 35 vol.%. The diffusivity of carbon dioxide in air at 25 °C and 3 atm is 0.0062 cm²/s. Calculate the rate of transfer of CO2 across the two planes, assuming (Diffusion of CO2 through a stagnant air layer).

Question 7 What is vacuum pressure? "It is the pressure above the atmospheric pressure, measured using a gauge." "It is the pressure below the atmospheric pressure, measured using a gauge." It is the sum of the atmospheric and gauge pressures. It is the pressure of the atmosphere.