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Q1: Rectangular channel flow reactors are a useful basis for the development of electrochemical synthesis as part of a green and sustainable chemica manufacturing involving process electrification. A laboratory-scale electro chemical reactor, developed as channel flow cell, had length (L) of 30 cm, a cross-sectional width (B) of3.0 cm and a cross-sectional height (s) of 5.0 mm, and was designed so that the flow would be well-developed before it reached the electrodes embedded in the sides of the reactor. Operation of the cell occurred isothermally at293 K, for a liquid electrolyte (of viscosity 1.002 mPa s and density998.2 kg m) for the electro chemical conversion of a reactant. The diffusion coefficient of the reactant in the liquid electrolyte is 2.67 x 10° cm? s'a rectangularat293 K. See Answer
Q2: A simple rain gauge is just a cylinder into which rain falls. The rain gauge shown is a cylinder that is 12 cm deep and 2 cm in diameter. It currently filled with 2.5 cm of water. The relative humidity (RH = 100 x pa/pa*) of the ambient air is 40%. The air and the water are at 25°C and1 atm a) Find the steady-state molar flux at which water evaporates from the tube. Use both the dilute and concentrated solutions that are appropriate for this problem and compare the results. Identify the reasons for any similarities or differences in the results. b) What is the molar concentration of the water vapor in the rain gauge 5 cm from the top? c) Consider the effect of the wind on evaporation and concentration profile under the following conditions: i) a perfectly calm day ii) a light breeze iii) a strong windSee Answer
Q3: Ansell Inc. produces chemical-resistant gloves. Their chemicalpermeation test cell is shown in the illustration to the right. Theglove material is used as a thin membrane separating a liquidcompartment from a gas compartment. Nitrogen gas iscontinuously pumped through the gas side of the chamber to keepthe concentration of liquid vapor that has diffused across themembrane close to zero. Their test liquid is epichlorohydrin, a chemical we have used inour lab to crosslink polymers. According to Ansell, gloves made ofa neoprene-natural rubber blend (0.67 mm thick, density of 1.18g/cm3) are rated as "Good" in terms of permeation rate, whichmeans that the steady state permeation rate is no more than 90ug/cm2-min (or 1.6 x 10-8 mol/cm2-s).(E a) A typical value of a diffusion coefficient of a small organic molecule in a polymer is 5 x 10-7 cm2/s. Calculate thepartition coefficient HA of epichlorohydrin in neoprene-natural rubber using this value of DAB. b) Diffusion coefficients of molecules in most polymers are much higher than in other solids. Hence manipulation of HAlsa promising way to reduce permeation rates in polymeric gloves. Does the value of Ha found in part a) suggest that Ansell has successfully developed a material that will do a “good" jobof protecting your hands from epichlorohydrin? Explain your reasoning briefly. c) Sketch the steady-state molar concentration profile of epichlorohydrin in the neoprene rubber from the liquid phase,through the rubber and into the gas phase. That is, sketch the mass transfer equivalent of WRF Fig 16.2 for steady-state heat conduction as shown below. Only a qualitatively reasonable sketch is expected (no calculations are necessary), but draw it in terms of molarconcentration for each phase (liquid/solid/gas). Note that the density of the liquid and rubber phases are equal. See Answer
Q4:Dilute concentrations of toxic organic solutes can be degraded by a "biofilm" attached to an inert, nonporous surface. A biofilm consists of living cellSee Answer
Q5:P7.43 10 L of water are contaminated with 200 mmol phe- nol. The water must be cleaned up to contain no more than 5 mmol phenol before it can be discharged. This will be accomplished by pumping the solution into a vessel loaded with fresh activated carbon, waiting for the phases to equilibrate, then removing the liquid solution. How much activated carbon should be loaded into the vessel? Assume an operating tempera- ture of 20°C. Use the equilibrium data given with Prob. P7.42.See Answer
Q6:In microprocessors, thin metal circuitry lines are connected vertically using cylindrical "vias." These metal vias are surrounded by oxide to prevent short circuits; the oxide is deposited first and the vias are filled in afterwards. We have an oxide layer with empty vias that need to be filled with tungsten metal using chemical vapor deposition (CVD) through the instantaneous reaction below: WF:(g) + 3H-(g) → W(s) + 6HF(g) The oxide walls are "I" deep (z = 0 is at the top, z = L at the bottom) and the empty vias are 0.5 um in diameter. The tungsten does not coat the side walls; it is only deposited on the base of each via. The mole fractions of WF6 at the top of via is ywrs, and the system is not dilute. There is no forced convection. A. Draw a diagram of the process, showing the movement of the various species. State all assumptions. B. Develop mathematical expressions that relate the flux of tungsten hexafluoride (Nws) to the fluxes of the other pertinent species. Okay to drop the subscript z to simplify the notation. C. Simplify the general equation for NwFs (Fick's law) and the continuity equation to derive one differential equation that can be integrated to determine ywF6 (2). Assume steady state and constant T, P, and DAB- D. State the boundary conditions for this process (instantaneous reaction). E. Integrate your equation in Part C with your boundary conditions in Part D to derive an expression of the form ywrs = .... F. Derive an expression for the flux of WF, in the gas film, NwF6-See Answer
Q7:Chapter Thirteen Gas Absorption 13.2 An absorption column is to be designed to recover 99.5% of the NH3 from a feed stream, which is supplied at 72 °F and an NH3 partial pressure of 10 mm Hg. The feed stream contains 2100 lb/hr of air. The column operates at 1.0 atm, is supplied with pure water at 72 °F that flows at 1.5 times the minimum water rate. Hoy for the operation is 1.9 ft. a. Find the minimum water rate, in lb/hr. b. Find the height of the packing required if = 1.0.See Answer
Q8:13.3 A gas stream containing a valuable hydrocarbon (MW = 44) is scrubbed with a nonvolatile oil (MW=300, specific gravity = 0.90) in a tower packed with 1-inch Raschig rings. The entering gas analyzes 20 mole percent hydrocarbon with the remainder being an inert gas (MW = 29). The gas stream enters the column at 5000 lb/hr-ft2, and hydrocarbon-free oil enters the top at 10,000 lb/hr-ft. The column is 4 ft in diameter. Ninety-five percent of the valuable hydrocarbon is to be recovered. Use the equilibrium relationship and the equations for k,a and ka given below. Estimate the height of packing required.See Answer
Q9:13.4 An air-ammonia mixture, containing 1.5 volume percent NH3, at 95 °F and 1.0 atm is scrubbed in a packed tower with pure water at 95 °F. The outlet NH3 concentration must be no more than 0.1% to meet EPA regulations. a. What volume of this gas in acfm can be processed in a 2-ft diameter column packed with 1-in. ceramic Raschig rings if the gas-to-liquid mass flow ratio is 1.0? b. What height of packing is necessary if Hoy is 1.85 ft?See Answer
Q10:given dry bulb temperature is 35c wet bulb temperature is 27c to find with use of the provided psychrometric chart fig 1See Answer
Q11:given a mixture of o and co is kept in a container the molar fraction of the o is 0 4 to find 1 molar fraction of the co VPcCzj2UqSee Answer
Q12:given thick wall natural rubber pipe with outer diameter 40mm and inner diameter 32mm is in use for transport of 100 co _zu5dBoiASee Answer
Q13:1. Multistage Distillation Separation and VLE Consider the VLE conditions for a binary mixture of 2-propanol and 2-butanol. This process has a feed flow rate of 600 mol/s, where the feed enters as a mixture of vapor (110 mol V in feed) and liquid (490 mol L in feed), and an initial feed concentration of 65% 2-propanol and 2-butanol. The reflux ratio is given as R = 1, and a target top concentration of 98% 2- propanol and a bottoms concentration of 12% 2-propanol. a. Draw a PFD for this process. Construct xy-, Txy, and Pxy diagrams for this system, assuming either a constant T = 80 °C or a constant P = 760 mmHg. Reference Antoine's coefficients from the Table provided with HW2. b. Solve for the distillate and bottoms flow rates. c. Assume that the ratio of streams in the rectifying section of the column are defined by L/V = 0.5, while streams in the stripping section of the column are defined by L'/V' = 2.6, where the vapor returning to the column following the partial reboiler and V':B split is 50 mol/s (V"). Graphically determine the theoretical number of stages required by plotting this information on an x-y plot, including the q-line, TOL, and BOL d. Calculate the heat duty for the condenser (total) and reboiler (partial), assuming no heat loss (Que="0). The heat of vaporization for 2-propanol is ~39.85 kJ/mol and for 2-butanol is ~40.8 kJ/mol.See Answer
Q14:2. For this same binary separation (Part 1), prepare 3 graphically-solved/constructed McCabe Thiele Diagrams derivations, varying 3 specific specifications and solving for new flow rates or compositions (i.e., change ZF, R, and Target Purity). (note: you will likely be able to use a similar spreadsheet). Briefly discuss how each change affected the process (positively or negatively!).See Answer
Q15:1. Explain with schematic drawing the mechanisms of mass transfer. 2. What are the possible driving forces for mass transfer. 3. Explain Fick's Law. 4. Define each terms what they are and their units in SI of the following equation:See Answer
Q16:5. Explain the film theory and how the mass transfer coefficient is derived. 6. Explain with schematic plot the two film theory indicate PAL Al in equilibrium with what, PA and CA are equilibrium with Ab what and show their equation. Define such equation. 7. Derive the following overall mass transfer coefficients based on liquid side and gas side driving forces: 1 H₂ = + KL kp KG 1 1 Hak (3-187) (3-191)See Answer
Q17:8. Derive the following overall mass transfer coefficients based on the mole fractions. 1 7/24 K₂ KAky = = Ky ky 1 and 9. Derive and explain the other forms of overall mass transfer coefficients based on mole fractions as follows: -- - +2 141 || (3-198) + (3-199) m,k, (3-215) (3-216)See Answer
Q18:Example Estimate the diffusivity of ethanol (C,H,O) in a dilute solution in water at 288 K. Compare your estimate with the experimental value reported in Appendix A. (1.0*10^-5 cm²/s) V=167.1 cm³/molSee Answer
Q19:Absorption A combustion gas (22 kmol) from a large coal-fired power plants contains carbon dioxide 11.5 + a+f-d = _CO₂ (mol %) the rest is air. We want to remove a+f-d CO₂ (mol %). 80 50 " the CO₂ so that the cleaned gas contains 1.1+ This is done by contacting the combustion gas with a water-amine solution in a plate absorption column at about 60°C and 1.2 bar. The water-amine feed solution contains 1.0% CO₂ and the enriched solution leaving the bottom contain 5.32+3= % CO₂ The vapor liquid equilibrium relation is given by, y = 0.84x. Assume constant molar flows calculate the liquid flow rate and required number of plates. 103 = =See Answer
Q20:Q3. Choose a single answer. Show steps. The diffusivity of Argon in No at 20 °C and 1 atm pressure is 0.194 cm³/s. What would you expect the diffusivity of N: in Ar to be at 50 °C and 2.5 atm? Use the Chapman correlation. Does increasing the temperature or increasing the pressure have more effect on the diffusivity? Please comment A) 0.194 cm³/s B) 0.442 cm³/s C) 0.5 cm³/s D) 0.535 cm³/s E) 0.555 m³/s F) 0.535 m³/s G) 0.442 m³/s H) 0.09 cm³/s ) 0.09 m²/sSee Answer

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