Question (2 to 12 ) MCQ 2 A mixture of Benzene (C&H) in Toluene (C7Hg) is fed to a continuous distillation column. It is desired that the column produce a distillate with a composition of 0.94 mol fraction Benzene, and a bottom product with a composition of 0.04 mole fraction Benzene. If the feed stream enters the column at a rate of 151.04 kmol s1 and has a composition of 0.59 mol fraction Benzene, determine the molar flow of the distillate in kmol s¹ to 2.d.p. 3 The Bubble Point is defined as the as the temperature is raised. 4 For the diagram below, match the correct terms to the indicated lines, or points on the diagram. Please note: All selections must be correct be awarded marks. 5 You have a mixture of two components A and B. A sample of the mixture is taken and analysed and found to have a contain of 0.25 mass fraction A. If the relative molecular mass (RMM) for A and B are as follows: RMM A = 69 g mol-1 RMM B = 99 g mol-1 Then determine the mole fraction of component A in the mixture to 2.d.p. 6 From the selection of statements below, select all statements which are true, 7 You have a mixture of two components A and B. A sample of the mixture is taken and analysed and found to have a contain of 0.07 mole fraction A. If the relative molecular mass (RMM) for A and B are as follows: RMM A-34 g mol-¹ RMM B = 115 g mol-1 Then determine the mass fraction of component B in the mixture to 2.d.p. 8 A 200 Litre barrel containing an unknown mixture of ethanol and water has been located. A sample from this barrel is taken and the temperature of the sample is adjusted to 20 C. The composition of this 20 C mixture is measured using an hydrometer and found to be 45.39% by volume ethanol in water. Using the physical property data provided, determine the composition of ethanol in the mixture in terms of mole fraction to 2.d.p. 9 You have six sketches labelled A to F. Each sketch uses a black line to present the change in partial pressure with respect to liquid composition at a fixed system temperature. A red line is then used to try to indicate the region where Henry's Law applies to the data. the data 10 For the listed separation processes, match each process with their respective "separation agent": Please note: All selections must be correct to be awarded marks for this question. 11 A mixture of two components A and B are fed continuously to a distillation column, to produce a top distillate product, and a bottom product. The mass flow of the feed to the column is 132.64 kg s and has a composition of 0.50 mole fraction of component A. It is desired that the column produces a top product with a composition of 0.97 mole fraction of component A, and a bottom production with a composition of 0.03 mole fraction of component A Determine the molar flow of the top distillate product in kmol s¹ to 2.d.p. 12 A mixture of two components A and B are fed continuously to a distillation column at a temperature 335 K. The mass flow of the feed to the column is 530 kg s¹ and has a composition of 0.48 mole fraction of component A If the feed mixture boils at 405 K; determine the value of a for the feed mixture, based following thermodynamic datą. You should indicate your answer to two decimal places.

Consider the gas carburizing of a gear of 1020 steel at 927C°. Calculate the time in minutes needed necessary to increase the carbon content to 0.40% at 0.5 mm below the surface. Assume the carbon content at the surface is 0.90% and that the steel has a nominal carbon content of 0.20%. The diffusion coefficient of C in 1020 steel at this temperature is 1.28 x 10-11 m²/s.

Consider a given volume of liquid at a temperature ∆T below Tm with a free energy G₁, figure a. If Vs is the volume of the solid sphere, V, the volume of liquid, Asl is the solid/liquid interfacial area, GS and G are the free energies per unit volume of solid and liquid respectively, and Ysl, the solid/liquid interfacial free energy. (a) The free energy of the system without any solid present is G₁=_______ (b) If some of the atoms of the liquid cluster together to form a small sphere of solid, figure b, the free energy of the system will change to G₂ =_____ (c) Therefore, the formation of solid results in a free energy change ∆G =_______ (d) Determine the energy barrier AG* for homogenous nucleation using the information above.

Obtain the analytical solution of the partial differential equation that describes the concentra- tion profile for one-dimensional unsteady-state diffusion by the separation of variables technique.

A. A reactant A diffuses to a surface, at which a reaction occurs according to the following stoichiometry: A(g) → B(g) + C(g). Under what conditions can we ignore the convective flux of A? a. We cannot, because 2 moles of product gas (B+C) diffuse away from the surface for every 1 mole of reactant (4) that diffuses to the surface. b. If the medium above the surface is quiescent and the concentration of A is dilute throughout the medium. c. If the medium above the surface is quiescent and the concentration of both B and C are dilute throughout the medium. B. Why does convection not occur at a solid boundary? a. No slip in normal direction and no penetration in the tangential direction. b. No slip in tangential direction and no penetration in the normal direction. c. Because the reactant becomes trapped in the pores of the surface and cannot pass through. d. Both (b) and (c) are correct.

A. For 1-D steady-state diffusion in the z-direction, in which one molecule of A has a flux that is equal and opposite to one molecule of B, draw (A) a plot of concentration versus z-distance with curves for both CA and CB, and (B) a plot of partial pressure versus z-distance with curves for both PA and PB. B. In your own words, describe some key indicators that a mass-transfer situation should be analyzed as pseudo-steady state diffusion (as opposed to steady or unsteady-state diffusion).

Based on your performance on the second midterm, write a few sentences about how you might approach studying/preparing for the final differently or the same!

A liquid mixture (100 gmol/s) of 40 mol% n-hexane/60 mol% n-heptane at 10 atm pressure and 25°C is sent through an expansion valve, where the pressure drops to 1 atm, and into a flash tank, which is heated. Vapor and liquid are separated in the tank and leave at 1 atm and 85°C. Calculate the compositions and flow rates of the vapor and liquid streams leaving the tank. Calculate the amount of heat (kJ/s) added to the tank.

20 kg of water vapor at 1 bar is heated from 100 to 320°C. What is the enthalpy change calculated (a) from the steam table, (b) using the approximate Cp given in App. B, and (c) using the polynomial expression for C, given in App. B?

Natural gas (10 gmol/h, 96 mol% meth- ane, 4 mol % ethane) at 15 psig and 60°C is heated in a double-pipe heat exchanger to 160°C. If the heat is supplied by con- densing saturated steam at 30 psig, what flow rate of steam (g/h) is required?