Calculate the rate of diffusion of n-Butanol (A) across a film of non-diffusing water (B) solution of 1 mm thick at 25°C. The concentrations of n-Butanol on the opposite sides of the film are known to be 12 wt% and 4 wt% respectively. Data: the diffusivity of (A) in the solution is 0.95×10-9 m²/sec at 25°C, the density of (A) is 810 kg/m', the density of (B) is 1000 kg/m³ , MwtButanol) = 74.12 g/gmol, Mwt(Water) = 18 g/gmol.

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Consider a solid sphere, of radius R, which is placed in a large body of unstirred, aqueous solution, as shown in Figure 1. The dissolution of the solid A, is slow enough that quasi-steady-state can be assumed. Given the solubility of A in the solution is CA* at the surface of the sphere and assume there is a bulk diffusion in the solution (i.e. the term yA(NA+Nu) is not zero). 1.) Derive an expression for the concentration distribution of A in the solution; and 2.) develop a mathematical relationship for molar flow rate of A, entering the solution at the surface of the sphere. FLUID SOLID 'A' &r Rs

Acetic acid (CH3COOH) diffuses across a 1-mm thick film of non-diffusing water. The concentration of acetic acid on opposite sides of water film are 9% by weight (density=1012 kg/m³) and 4% by weight (density=1003.2 kg/m³). Calculate the rate of diffusion of acetic acid at 17 °C. DATA: The diffusivity of acetic acid in water at 25 °C = 1.11 x 109 m²/s Viscosity of acetic acid solution at 25 °C = 1.1336 x 10-³ Pa. Viscosity of acetic acid solution at 17 °C = 1.2883 x 10-³ Pa.s

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A binary gaseous mixture of components A and B at a pressure of 1 bar and temperature of 300 K undergoes steady-state equimolar counter diffusion along a 1-mm-thick diffusion path. At one end of the path the mole fraction of component A is 70%, while at the other end it is 20%. Under these conditions, DAB = 0.1 cm2/s. Calculate the molar flux of component A.

A wet sphere of gelatin gel at a temperature of 20 "C contains a uniform concentration of urea of 0.05 kg mol/m'. The sphere has a diameter of 16 mm. The sphere is suddenly immersed in turbulent water which initially contains urea of concentration 0.1 kg mol/m'. The diffusion coefficient of the urea in the gelatin gel is 8.59 * 10*" m/s. The convective mass transfer coefficient ke is 1.07375 x 10 m/s and the equilibrium distribution coefficient K is 1. For radial mass transfer only, listing your assumptions, calculate, (a) the concentration at a distance of 4,8 mm from the midpoint of the sphere after 25.87 hours of mass transfer. (b) the time by which the concentration, c, at the centre of the sphere is 0.09975 kg mol/m3

A spherical mothball initially with radius, Ro, is shrinking in volume due to the sublimation of naphthalene through the air in a large room.  At room temperature (T) and pressure (PT), the naphthalene (with molecular weight as MWa) in the mothball exerts a vapor pressure (VPa).  It is of interest to investigate the rate at which the mothball is shrinking due to the diffusion of naphthalene in an air-rich environment. A. Illustrate the physical model/s that can describe the diffusion of naphthalene through the air-rich environment (room).  Indicate the control volume/s (differential volume/s) as an expression of the transfer area and distance.  Specify the components needed in establishing the shell balance.  Indicate the boundary conditions and illustrate the direction of transfer in each physical model.  Note:  Express the radial distance from the mothball surface as r, while the shrinking radius of the mothball is expressed as R.  Use and define subscripts, as necessary. B. For each…

A quiescent body of water has a depth of 600 mm. The DO level at the bottom after 16 days is 3.5 mg/l when the surface is exposed to the atmosphere at a temperature of 25o Determine the DO of the water body. The saturated DO at 25oC is 8.5 mg/l and the diffusion coefficient (kd) at 25oC is 2.5 x 10-3 mm2/s.

A steel sheet is exposed to a nitrogen rich atmosphere at 900°C and achieves steady-state diffusion. The diffusion coefficient for nitrogen at this temperature is 1.85 x 10-10 m2 kg and the diffusion flux is 1.0 x 10-7 If the initial concentration of sec m².sec kg nitrogen in the steel at the high-pressure surface is 2 at what distance into the sheet m39 will the concentration of nitrogen be 0.5 *9? m3 4 360 words D Focus 255% e Type here to search IA 5:02 PM W 2/24/2022 10 165HZ V WQHD |. ROG ZEPHYRUS 100% DCI-P3 PANTONE Validated F5 F9 F10 ESC AURA DELETE %24 & %3D P www ENT G K