Review Exercises for the Final Examination PDF

Review Exercises for the Final Examination 1. The volume of water in a reaction is given by the equation: 3 -2 2 V (ft ) = 3.53*10 exp (2t ), where t is time in hours. -2 A) What are the units of 3.53*10 and 2?...

Review Exercises for the Final Examination 1. The volume of water in a reaction is given by the equation: 3 -2 2 V (ft ) = 3.53*10 exp (2t ), where t is time in hours. -2 A) What are the units of 3.53*10 and 2? 3 B) If the equation be given for the volume in m as a function of t (seconds). Determine the formula. 2. A mixture is 10mol% ethyl alcohol, 75mol% ethyl acetate (C4H8O2), and 15 mol% acetic acid. Calculate the mass fraction of each compound. What is the average molecular weight of the mixture? What would be the mass (kg) of a sample containing 25.0 kmol of ethyl acetate? 3. A stream of humid air enters a condenser in which 95% of the water vapor in the air is condensed. The flow rate of the condensate (the liquid leaving the condenser) is measured and found to be 225L/h. dry air may be taken to contain 21mole% oxygen, with the balance nitrogen. Calculate the flow rate of the gas stream leaving the condenser and the mole fraction of oxygen, nitrogen, and water in this stream. 4. A stream containing 5.15% chromium, Cr, is contained in the waste water from a metal finishing plant. The waste water stream is fed to a treatment unit that removes 95% of the chromium in the feed and recycles it to the plant. The residual liquid stream leaving the treatment unit is sent to a waste lagoon. The treatment unit has a maximum capacity of 4500kg waste water/h. If waste water leaves the finishing plant at a rate higher than the capacity of the treatment unit, the excess (anything above 4500kg/h) bypasses the unit and combines with the residual liquid leaving the unit, and the combined stream goes to the waste lagoon. Waste water leaves the finishing plant at a rate m 1 = 6000kg/h. Calculate the flow rate of liquid to the waste lagoon, m 6(kg/h), and the mass fraction of Cr in this liquid, x6(kg Cr/kg). 5. Methane is burned with oxygen to yield carbon dioxide and water. The feed contains 20 mole% CH4, 60% O2, and 20% CO2, and a 90% conversion of the limiting reactant is achieved. Calculate the molar composition of the product stream. 6. 500kg/hr of steam drives a turbine. The steam enters the turbine at 44 atm and 450°C at a linear velocity of 60 m/s and leaves at a point 5 m below the turbine inlet at atmospheric pressure and a velocity of 360 m/s. The turbine delivers shaft work at a rate of 70 kW, and the heat loss from the turbine is estimated to be 11.6KW. Calculate the specific enthalpy change associated with the process. 7. Trichloroethylene, a widely used degreasing solvent for machine parts, is produced in a two-step reaction sequence. Ethylene is first chlorinated to yield tetrachloroethane, which is dehydrochlorinated to form trichloroethylene. C2H4(g)+2Cl2(g)→C2H2Cl4(l)+H2(g): ∆Hor=-385.76KJ C2H2Cl4(l)→C2HCl3(l)+HCl(g) The standard heat of formation of liquid trichloroethylene is -276.2 kJ/mol. a) Use the given data and tabulated standard heats of formation of ethylene and hydrogen chloride to calculate the standard heat of formation of tetrachloroethane and the standard heat of the second reaction. b) Use Hess’s law to calculate the standard heat of the reaction C2H4(g)+2Cl2(g)→C2HCl3(l)+H2(g)+HCl(g) c) If 300 mol/h of C2HCl3(l) is produced in the reaction of art (b) and the reactants and products are all at 25 C and 1atm, how much heat is evolved or absorbed in the process? (Assume = H ) 8. Public concern about the increase in the carbon dioxide in the atmosphere has led to numerous proposals to sequester or eliminate the carbon dioxide. An inventor believes he has developed a new catalyst that can make the gas phase reaction ( ) ( ) ( ) ( ) proceed with 35% conversion of the CO2. The source of the hydrogen would be from the electrolysis of water using electricity generated from solar cells. Assume that 5mol of CO2 enter the reactor at 800°C together with 8mol of H2 at 100°C. Determine the heat of reaction if the exit gases leave at 1atm and 600°C.