Questions and Answers of Introductory Chemical Engineering Thermodynamics

Determine the equilibrium composition of the following isomers of C3H8O: at 500 K and 1 bar: ethyl methyl ether (1), n-propyl alcohol (2), and isopropyl alcohol (3). The following Gibbs energies of
Use ThermoSolver to determine the equilibrium composition from the combustion of butane and a stoichiometric amount of air at 2000 K and 50 bar. Consider H2O, H2, CO, CO2, NO, and NO2 as possible
Develop a methodology for calculating Δu according to the path shown in Figure E5.3A, in which the change in T occurs when intermolecular interactions are important.
Repeat Example 5.4 using the Lee–Kesler generalized correlation data for enthalpy departure to account for nonideal behavior.
3 moles of pure water are adiabatically mixed with 1 mole of pure ethanol at a constant pressure of 1 bar. The initial temperatures are the pure components are equal. If the fi nal temperature is
A stream of pure water fl owing at 1 mol/s is adiabatically mixed with a stream containing equamolar amounts of water and ethanol, also fl owing at 1 mol/s. This steady-state process occurs at a
Fit the data in Problem 6.53 to the form:(a) Use the analytical method to come up with an expression of the partial molar volume of ethanol.(b) Determine the values at x1 = 0.8, x1 = 0.4, and x1 =
In the discussion of cubic equations of state (Section 4.3), it was stated that the vapor–liquid dome could be constructed from a subcritical isotherm generated by the equation of state.The
Outline the calculations that you would do to produce the graph for the fugacity coeffi cient of methane in a binary mixture of methane and ethane, as shown on the left side of Figure 7.3.Show the
Consider the binary mixture depicted in Figure 7.5. Which interaction is stronger, the like interactions, a-a, or the unlike interactions, a-b?
Consider a binary liquid consisting of species a and b. The activity coeffi cient, based on the Lewis/Randall rule, for species a vs. mole fraction a is plotted in Figure E7.7A. On the same graph,
Repeat Problem 8.65 using the Peng–Robinson equation of state. Use a value for the binary interaction parameter of:(a) 0(b) 0.077Problem 8.65Using the equation of state method, construct a Pxy
You are considering building a solar power plant which uses CCl2F2 as its working fl uid. It enters the turbine as a saturated vapor at 1.7 MPa and leaves at 0.7 MPa. Based on the ideal Rankine
Calculate the van der Waals parameters from critical point data for the following gases: He, CH4, NH3, and H2O. Explain the relative magnitudes of a and b from a physical basis.
(a) Use the data in the steam tables to come up with an expression for the second virial coeffi cient for water vapor.(b) Calculate the value of BH2O using the principle of corresponding states.
Calculate the second virial coeffi cient, B, for C6H6 over the temperature range 100–900 K directly from the values of the Lennard-Jones parameters reported in Table 4.2. Compare the values to the
Experimental values for the second virial coeffi cients for NH3 versus temperature are reported in the following table. Use these data to obtain the best estimates that you can for the Lennard-Jones
Calculate the second virial coefficient, B11, for pure Ar, B22 for pure CH4, and the second virial coefficient for the unlike interaction in a mixture, B12 at 239.8 K directly from the values of the
Calculate the van der Waals parameters from critical point data for the following gases: benzene, toluene, cyclohexane. Explain the relative magnitudes of a and b from a physical basis.
Ethanol (1) and n-hexane (2) are in equilibrium at 75°C. There are two liquid phases and one vapor phase present (VLLE). The compositions of the liquid phases are:The saturation pressures at 75°C
Para-xylene (p-xylene) is used as a raw material to make polyester fi bers. Billions of pounds are produced every year. It is manufactured by reforming crude oil. p-Xylene must then be separated.In
Your roommate likes really, really cold beer. How cold can you set the freezer temperature to have the beer be as cold as possible without its freezing and causing a big mess? Assume beer is 4 mass%
Bismuth(a) and cadmium(b) form a eutectic at 144°C and xa = 0.45. They are also completely immiscible in the solid phase. The melting points for bismuth and cadmium are 271°C and 321°C,
The excess Gibbs energy for a binary mixture of liquid a and liquid b is given by:where T is in [K]. The solids of these species are completely immiscible. The enthalpies of fusion and melting
Antimony and lead form a eutectic at 251°C and 11.2 weight percent antimony. The enthalpy of fusion and melting point of lead are as follows:As best you can, determine the composition of the
phase diagram for the solid liquid equilibrium of a binary mixture of silver (Ag) and copper (Cu) is shown below. Answer the following questions. Note that the weight percentage is on the bottom and
A phase diagram for a binary mixture of ammonia (1) – water (2) at 1 atm is shown in the following fi gure. Answer the following questions. Illustrate whenever possible the information you obtain
A well-insulated container has 1.0 kg ice and 1.0 kg liquid water at 0°C in equilibrium. 1.0 kg of liquid ethanol at 0°C is added to the system. At equilibrium, what is the fi nal state of the
The following solid–liquid equilibrium data are available for a binary mixture of C and metastable γ—Fe.From these data estimate the melting point and enthalpy of fusion of γ—Fe. T[C] 1148
When 9 g of urea (CH4N2O) are added to 1 kg of acetone at 1 bar, the boiling point of acetone raises 0.24 K. The normal boiling point of acetone is 329.2 K. From this datum, estimate acetone’s
Ethylene glycol, C2H6O2, is used as an antifreeze to keep the water in the radiator of your car from freezing in the winter. Estimate the fraction of antifreeze, by volume, that you need to keep from
What is the minimum pressure required to desalinate seawater by reverse osmosis?
Find the osmotic pressure of a solution of 0.5 g of sucrose (C12H22O11) in 500 g water at 25°C and 1 bar.
Use ThermoSolver to fi nd the activity coeffi cient model parameters for the data presented in Problems 8.55 and 8.56.Problems 8.55The following vapor–liquid equilibrium data have been reported for
Use ThermoSolver to determine the dew-point temperature and composition of a vapor mixture of 0.2 mole fraction n-hexane, 0.25 cyclohexane, 0.25 benzene, and 0.3 toluene at pressures of 1 bar and at
Use ThermoSolver to determine the bubble-point temperature and composition of a liquid mixture of 0.2 mole fraction n-hexane, 0.25 cyclohexane, 0.25 benzene, and 0.3 toluene at 1 bar and at 20 bar,
Use ThermoSolver to determine the dew-point pressure and composition of a vapor mixture of 0.25 mole fraction methanol, 0.35 acetone, and 0.4 n-hexane at temperatures of 40°C and 200°C
Use ThermoSolver to determine the bubble-point pressure and composition of a liquid mixture of 0.25 mole fraction methanol, 0.35 acetone, and 0.4 n-hexane at temperatures of 40°C and at 200°C
Consider a system with liquid containing 30% n-pentane (1), 30% cyclohexane (2), 20% n-hexane (3), and 20% n-heptane (4) at 1 bar. Determine the temperature at which this liquid develops the fi rst
Consider a system with vapor containing 30% n-pentane (1), 30% cyclohexane (2), 20% n-hexane (3), and 20% n-heptane (4) at 1 bar. Determine the temperature at which this vapor develops the fi rst
A compressed liquid feed stream containing an equimolar mixture of n-pentane and n-hexane fl ows into a fl ash unit as shown in Figure E8.3 at fl ow rate F. At steady state, 33.3% of the feed stream
Apply the appropriate material balance equations to verify that the lever rule gives the relative amount of species in each phase along a tie line as depicted in Figure 8.2. Pressure Psys Psat
A binary vapor mixture contains 48% ethanol(a) in water(b) at 70°C. Determine the pressure at which this vapor develops the fi rst drop of liquid. What is the liquid composition? The excess Gibbs
At high pressures, both the vapor and liquid phases may be nonideal. Consider a binary mixture of a and b with vapor-phase mole fraction and T known. Develop a set of equations and a solution
At 50°C, a binary mixture of 1,4-dioxane(a) and water(b) exhibits an azeotrope at xa = 0.554 and a pressure of 0.223 bar. Use this datum to estimate the value of the two-suffi x Margules parameter
Show that the composition of the vapor and liquid phases must be equal at an azeotrope.
Liquid–vapor equilibrium data have been collected for a binary system of benzene (1)–cyclohexane (2) at 10°C. Mole fraction of liquid and vapor vs. total pressure are reported in Table E8.9A.5
Calculate the three-suffi x Margules parameters, A and B, for the system of Example 8.9.Example 8.9Liquid–vapor equilibrium data have been collected for a binary system of benzene (1)–cyclohexane
Determine the model parameters for the two-suffi x and the three-suffi x Margules equations using the liquid–vapor equilibrium data for a binary system of benzene (1)–cyclohexane (2) at 10°C.
Calculate the solubility of O2 from air in the atmosphere in equilibrium with liquid H2O at 25°C. Report the answer in mole fraction and in molarity.
Determine the solubility of N2 in H2O at 300 bar and 25°C. Take, N = 3.3 x 10-5 [m/mol]
Using the Peng–Robinson equation of state, calculate the saturation pressure of pure (i) propane, (ii) n-butane, and (iii) n-pentane at 300 K by using fugacity coefficients to calculate the
Using the equation of state method, determine the equilibrium composition in the vapor phase and the system pressure of a mixture of methane (1) and n-pentane (2) with a liquid mole fraction of x1 =
Repeat Example 8.15 using the Peng–Robinson equation of state. Compare your answer to the reported measured value of P = 69.1 bar and y1 = 0.95.Example 8.15Using the equation of state method,
The following data are available for vapor–liquid equilibrium of the methane (1) –n-pentane (2) binary system at 37.78°C. Compare how well the van der Waals and Peng–Robinson equations can
Repeat Example 8.17 for the Peng–Robinson equation with values of the binary interaction parameter, k12 of 0.025, 0.05, and 0.10.Example 8.17The following data are available for vapor–liquid
Calculate the equilibrium composition of the two liquid phases in a binary mixture of methyl diethylamine(a) and water(b) at 1 bar and 20°C. Solve this problem in two ways; by graphical methods
Find a graphical solution to Example 8.19 by determining where the Gibbs energy of the system is at a minimum.Example 8.19Calculate the equilibrium composition of the two liquid phases in a binary
Apply the criterion for inherent instability of a single liquid phase to determine the composition range at which the system in Example 8.19 will spontaneously split into two phases.Example
A binary mixture exhibits vapor–liquid–liquid equilibrium at 300 K. The excess Gibbs energy is described by the two-suffi x Margules equation with A = 6235 [J/mol]. Determine the composition of
Find the eutectic point for a binary mixture of cadmium and lead. You may assume that the solid phases of these metals are completely immiscible and the liquid is completely miscible.The following
At what temperature does seawater boil? The concentration of NaCl in seawater is 3.5% by weight.
Consider the following reaction where gaseous components A and B react to form solid C:This reaction proceeds to equilibrium at 500 K and 4 bar, where the following quantities of species are present:
Your boss has asked you to come up with a scheme to make a product through chemical reaction. In doing the thermodynamic analysis, you determine that Δgorxn > 0. Your colleague claims that because
Consider the following reaction: The Gibbs energy of reaction at 298 K is determined to be and at a given temperature, the equilibrium constant is reported to be KT = 16. Now consider the reaction
At a given temperature, pressure, and initial composition, the equilibrium mole fraction of species C for the following reaction:is found to be 0.75. What is the value of the mole fraction if the
At 300 K and 1 bar, the equilibrium constant for the following reaction:is reported to be 10. What is the equilibrium constant at 300 K and 10 bar? You may assume ideal gas behavior. A(g) + B(g) C(g)
Consider the gas phase hydrogenation reaction of propylene to form propane:To increase the equilibrium conversion, would it help to(a) Increase the pressure?(b) Increase the temperature?(c) Add an
Your colleague reports that the conversion to n-butane from the gas phase hydrogenation reaction of 1-butene increases as temperature increases:Is this possible? Explain. C4Hs(g) + H(g) C4H0(g)
Which of the following conditions would you use if you needed to develop an industrial process to produce ethanol from acetylene? Explain.(a) 25°C and 1 bar.(b) 250°C and 1 bar.(c) 25°C and 150
Consider the following liquid phase reactions: A plot of the concentrations in [mol/L], of A, B, and C in a constant-volume batch reactor operating isothermally at 500 K is shown in the following fi
The standard half-cell potential for the reduction of water to form hydroxyl ion in Table 9.1 is reported as -0.828 V. If instead we write the reaction:what should we use for the half-cell potential?
Consider an electrochemical cell with a 1 m concentration of sodium ions and Al and Pt electrodes electrically connected together. Will the Al spontaneously dissolve into solution?
Rank in order from largest in magnitude to smallest in magnitude the activity coefficients of the solute in the following aqueous solutions: 0.1 m sucrose, 0.1 m NaCl, 0.1 m CaCl2.Explain.
An electrochemical cell has Ag electrodes and an electrolyte containing different concentrations of AgNO3 solutions separated by a salt bridge. When the two cell compartments have AgNO3 concentration
Gallium arsenide (GaAs) is a III-V semiconductor, which is often considered for applications where the speed of carrier transport is crucial (lasers, high-frequency detectors).(a) Suggest an atom
Consider two semiconductors, one made of Si and the other made of Ge. Both are at room temperature and doped with 1015 phosphorous atoms.(a) Which semiconductor has the greater number of free
Consider two semiconductors, one made of Si and the other made of Ge. Both are at room temperature and doped with 107 phosphorous atoms.(a) Which semiconductor has the greater number of free
At 25°C and 1 atm, the Gibbs energy of reaction to produce liquid hydrogen peroxide (H2O2) from liquid water has been measured to be 116.8 kJ/mol. From this value determine the (Agf. 298) HO*
Consider a system initially charged with 1 mole of pure I2 that is maintained at 1300 K and 1 bar in which the following dissociation reaction occurs:For monatomic iodinePlot ΔH, TΔS and ΔG as a
Calculate the Gibbs energy of formation of NH3 at 1000 K. Remember that the Gibbs energies of formation of the elements are still zero at this temperature.
Consider the hydrogenation reaction of 1-butene to butane by the following reaction:The feed fl ow ratio is 10 moles H2: mole C4H8. Consider a reactor temperature of 1000 K and reactor pressure of 5
One step in the manufacture of sulfuric acid is the oxidation of sulfur dioxide to sulfur trioxide.Consider performing this oxidation at a pressure of 1 bar with an excess of 100 mole % oxygen, using
Calculate the equilibrium constant in Problem 9.21, accounting for the variation of Δhrxn o with temperature.Problem 9.21Consider the hydrogenation reaction of 1-butene to butane by the following
Consider the industrial production of cyclohexane, C6H12, by the gas-phase hydrogenation of benzene, C6H6. Assume that this process is carried out by two reactors in series as shown below.The fi rst
You are a process engineer in charge of growing solid silicon from a feed of SiCl4 and H2 gases. The growth process can be described by the following chemical reaction:The reactor pressure is 100
Consider the production of 1,1-dichloroethane (C2H4Cl2) from ethylene (C2H4) and chlorine (Cl2). This gas-phase reaction is the fi rst step in producing polyvinyl chloride (PVC). The feed ratio of
The following SO2 partial pressures have been observed from the reaction:From these data, calculateYou may assume that each of the solids forms distinct phases and all are immiscible with one
Fuel cells produce electricity from hydrogen. The life of the fuel cell depends on producing relatively pure hydrogen. Methane (natural gas) is often used as a feed to produce hydrogen.Consider the
A vessel contains a liquid and a vapor phase in equilibrium at a pressure of 0.1 atm. The vapor phase contains 100 moles of species A and 200 moles of species B. The liquid phase contains 500 total
Gaseous hydrogen can be produced by the steam cracking of methane in a catalytic reactor at 500°C and 1 bar according to the following reaction:(a) If 5 moles of steam are fed into the reactor for
You have been tasked with the removal of H2S and SO2 from an industrial stack. The following reaction is proposed to dispose of both species at once:Consider this reaction at 500°C. PvT data for H2S
A gas mixture containing 1 mol/s H2, 2 mol/s CO and 1 mol/s CO2 is fed into a furnace at 1.5 bar. In addition to the species at the inlet, the outlet stream is measured to contain 0.40 mol/s of H2O
Solid species A reacts with gas B to form gas C with the following stoichiometry:At 500 K, the equilibrium constant for the reaction is K = 4. The system is held at a constant pressure of 3 bar and
Consider a mixture of 1-propanol(a) and water(b) in vapor-liquid equilibrium at 25°C. The liquid has a mole fraction xa = 0.2. The three-suffi x Margules equation parameters are:In addition,
H2 gas is needed as a gas source for fuel cells. You want to generate H2 through a gas phase reaction of n-pentane (C5H12) with steam (H2O). You may assume the only by-product formed is carbon
One step in the manufacture of solar cells is the growth of solid silicon from gas feed. Consider a feed source of pure chlorosilane that undergoes the following reaction:You are considering a
Pure H2O fl ows through a porous bed of solid carbon at 1000 K and 0.5 bar to produce H2 and CO gases. Answer the following questions. You may assume Δh°rxn = const.(a) At equilibrium, how much H2
Solid titanium can be produced by reacting titanium tetrachloride gas with molten magnesium liquid using the following reaction:You wish to react 40% of the magnesium liquid at constant pressure and
Consider the production of ethanol from acetylene and water at 355 K and 1 bar by the following reaction:(a) If the feed contains an equimolar mixture of reactants, calculate the equilibrium

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