What is the value of the flux (kmol/m^3.s) of water vapor through a stagnant film of estimated thickness 1.5mm on the water surface?

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In an accident a container containing ethanol(s.g 0.789) falls down in a room of dimension 1*1*2(all in m). Ethanol forms a layer of 2mm. Ethanol vaporizes and diffuses through a stagnant film of air of thickness 2.5mm. What will be the time required for the water layer to disappear completely. The diffusivity of ethanol in air is 2.567*10^-5 m^2/s. the total pressure is 1.013 bar and the pressure of ethanol in bulk air is 0.02244 bar and at the ethanol-air interface is 0.02718bar. The temperature is 25.2°C.

asked Sep 21, 2022 in Mass Transfer by Julian (37.1k points)

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Oxygen diffuses through a stagnant layer of air, 1mm thick, ambient temperature 28°C and 1atm total pressure. The partial pressure of oxygen on two sides of layer is P1=0.9atm and P2=0.1atm respectively. Calculate the value of Molar flux (in mol/m^2.s) with respect to an observer moving with molar average velocity. Calculate this value at the end of the path where P2=0.1atm. Use R=8.205*10^-5m^3atmK^-1mol^-1.

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Which of the following statements are correct? (a)Water vapor diffuses through non-diffusing hydrogen and oxygen

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What will be the values of the diffusivities (in cm^2/s) at the mean gas-film temperature?

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The value of a ratio of N flux of A to the total N flux for a steady state equimolar counter diffusion is

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In sulphuric acid plants dry air is used for burning of sulphur. Air is dried in contact with concentrated Sulphuric acid. Moisture diffuses through a layer of air, reaches the surface and gets absorbed in it. Here air is said to be non-diffusing were as moisture is diffusing. Which of the following statements are correct?

asked Sep 21, 2022 in Mass Transfer by Julian (37.1k points)

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For a steady state equimolar counter diffusion of A and B. The N flux of A is ________

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Consider steady-state equimolar counterdiffusion through the converging-diverging tube. Given: r1=1cm; r2=2cm; NA=10^-6 kmol/m^2.s at the vessel 1 end of the tube. The rate of transport of B at the vessel 2 end of the tube is

asked Sep 21, 2022 in Mass Transfer by Julian (37.1k points)

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Equimolar counterdiffusion of A and B occurs through a spherical film of i.d=ri and thickness δ. The flux of A is NA1 at r=ri. The flux through a flat film of the same thickness is NA2. if NA1 is larger than NA2 by 5%, the film thickness δ is

asked Sep 21, 2022 in Mass Transfer by Julian (37.1k points)

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In order to prepare Lithium nitride, air is passed gently over a reactor. Suppose that Nitrogen diffuse to a length 5cm before getting reacted with Lithium. Nitrogen reacts with lithium quickly so that partial pressure of Nitrogen at that point is 0. Reactor is a cylinder of length 10cm and diameter 2cm. Assume air to be a mixture of Nitrogen and Oxygen only. The temperature is 298K and total pressure 1atm. Diffusivity of N2 in O2 is 2*10^-5m^2/s. Calculate the Molar flux (mol/m^2.s) of N2 at a distance of 2.5cm from the top with respect to an observer moving with twice the mass average velocity a direction towards the liquid surface. (R=8.205*10^-5m^3atmK^-1mol^-1). Assume z=0 at the top of the reactor.

asked Sep 20, 2022 in Mass Transfer by Julian (37.1k points)

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A mixture undergoing multicomponent diffusion is analyzed through the Maxwell-Stefan approach. With regard to this approach which among the following statements are incorrect? The difference in the partial pressure of the Component A over a small distance ∆z (AB)is proportional to

asked Sep 20, 2022 in Mass Transfer by Julian (37.1k points)

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If all the components except 1 of the multicomponent diffusing mixture are inert, then what will be the expression for Diffusivity of component 1 in the mixture?

asked Sep 21, 2022 in Mass Transfer by Julian (37.1k points)

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Find the diffusivity through slab if N flux of A 4 mol/sq.m sec, concentration difference is 2mol/cu.m and distance is 3 m.

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In industries titanium is hardened through diffusion of carbon. The concentration of carbon at 1mm into the surface of the titanium slab is 0.25kg/m^3 and at 3mm the concentration is 0.68kg/m^3. The rate at which the carbon is entering into its surface is 1.27*10-9kg/m^2.s. calculate the value of diffusion coefficient of carbon.

asked Sep 20, 2022 in Mass Transfer by Julian (37.1k points)

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The mass flow rate of a component in a mixture in X-direction is 2kg/s. The area vector at a particular cross-section is (1.1, 3.2, 5.4) cm2. Calculate the value of flux (kg/cm2.s) through the cross-section.

asked Sep 20, 2022 in Mass Transfer by Julian (37.1k points)

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Find the diffusivity of AB in sq.m/sec if N flux of A 5 mol/sq.m sec, concentration difference is 2mol/cu.m and distance is 3 m.

asked Sep 21, 2022 in Mass Transfer by Julian (37.1k points)

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Find J flux of A ( xA = 0.5) if the total N flux is 6 mol/sq.m sec and N flux of A is 3 mol/sq.m sec.

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If the value of N flux of A to the total N flux is 1 then it is a steady state diffusion of non-diffusing B.

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A napthelene hemisphere is placed on a glass plate and a napthelene ball of identical diameter is kept suspended in the stagnant air in two large rooms. The respective shapes of the ball are maintained while they sublime and reduce in size. Which of the following statements are true in this connection?

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For a Steady state diffusion of A through Non- diffusing B. N flux of B= ______

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The value of N flux of A under steady state non-diffusing B with diffusing A is _________

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Find the change in concentration for a steady state equimolar counter diffusion if D(AB)= 6 sq.m/sec, the change in distance is 2 m and the N flux of A is 5 mol/sq.m sec.

asked Sep 21, 2022 in Mass Transfer by Julian (37.1k points)

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Find the flux of A ( xA= 0.2) if Total flux is 5 mol/sq.m sec and J flux of A is 2 mol/sq.m sec.

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For two particles at steady state collision of A and B, J flux of A is 2 mol/sq.m sec find the J flux of B.

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Find the total flux for a particle A and B in a steady state if flux of A and B is 2.44 and 4.44 mol/sq.m sec.

asked Sep 21, 2022 in Mass Transfer by Julian (37.1k points)

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