Questions and Answers of Fundamentals Of Chemical Engineering Thermodynamics

A lake initially contains 20,000 kg of water and has a uniform temperature of 20°C. The ambient pressure is P = 1 bar. During the course of a day, the following events affecting the lake occur: 200
One kilogram of steam is placed in a piston-cylinder device, initially at P = 1 bar and T = 100°C. The steam is heated at constant pressure to T = 200°C.A. Find the heat and work for this process.
In a large chemical plant, steam is used as a heat source in several different processes. The steam condenses in heat exchangers, and the liquid water is recycled to a boiler, which converts it back
An adiabatic valve operates at steady state. Saturated liquid water at P = 5 bar enters. The exiting stream is a saturated liquid–vapor mixture at P=1 bar. What is the quality of the exiting stream?
10 mol/s of gas enters a steady state, adiabatic nozzle at T = 300°C and P = 5 bar and leaves at T=100°C and P = 1 bar. Find the exiting velocity of the gas if it is:A. SteamB. Nitrogen, modeled as
This problem examines the effect of mixing water at two different temperatures and/or two different phases, such as dropping ice cubes into warm water. Assume that ΔHfus = 333.55 J/g, that CP for
Superheated steam enters a nozzle that has an inlet diameter that measures 2.5 cm and an outlet diameter that measures 1 cm. Its outlet velocity has been measured at 30 m/s. The steam that enters the
A rigid, 10 m3 vessel initially contains 100 kg of water/ steam at P = 2 bar. 10 kilograms of steam at P = 5 bar and T = 300°C is gradually added to the vessel. During the same time period, heat
A vessel initially contains 1000 kg of saturated liquid water at T = 30°C, which needs to be cooled. The vessel is adiabatic but has a piston that allows pressure and volume to be changed and a
Water at P = 25 bar and T = 200°C enters a steadystate flash chamber with a flow rate of 5 kg/s. The liquid and vapor streams exiting the flash chamber are both at P = 1 bar.A. If the flash chamber
This problem presents a comparison of the work required in adiabatic pumps and compressors.A. Saturated water vapor enters a steady-state compressor at P = 1 bar. Estimate the work required to
A two-step, steady-state process is used to compress 100 kg/min of nitrogen from P = 1 bar and T = 250 K to P = 10 bar and T = 250 K. First, an adiabatic compressor is used to convert the nitrogen
1 kg of nitrogen is contained in a piston-cylinder device. The nitrogen is isothermally compressed from P = 1 bar to P = 10 bar at T = 300 K. Find the initial volume, final volume, and work and heat
20 lb-mol/min of the compound enters a steady-state boiler as saturated liquid at P = 1 bar. Find the rate at which heat is added if the exiting stream is:A. Saturated vapor at P = 1 atmB. Vapor at P
Initially, one lb-mol of the compound is placed in a piston-cylinder device at T = 25°F and P = 1 atm. The compound is heated at constant pressure. Find the heat (Q) added if the final state is:A.
A liquid stream contains 1 lbm/s of the compound at T = 100°F and P = 1 atm. It needs to be boiled and heated to P = 1 atm and 175°F, as that is the temperature at which it must enter a chemical
A steady-state distillation column is designed to separate benzene from toluene. The separation is nearly enough complete that, for the purposes of designing the reboiler and the condenser, we can
Several processes are described. Indicate whether each is reasonably modeled as reversible, and if not, indicate what aspect of the process makes it irreversible.A. The inside of a refrigerator is at
Find the change in entropy for the system in each of the following processes.A. The system is 5 kg of initially saturated steam at P = 1 bar, and it is heated isobarically to 300°C.B. The system is
A heat reservoir is at 50°C. Find the change in entropy of the heat reservoir whenA. 1 kJ of heat is added.B. 1 kJ of heat is removed.C. Heat is added at a rate of 100 W for a total of one hour.
The system is 100 grams of a solid that has CP = 0.3 J/g · K. Find the change in entropy whenA. It is heated reversibly from 300 K to 500 K.B. It is cooled reversibly from 50°C to 25°C.C. It is
A system is operating at a steady state. Find the rate of at which entropy is generated inside the system for each of the following cases.A. The system is adiabatic. 100 kg/min of saturated steam
An inventor claims to have built a machine that operates as follows: 100 kg/min of steam at T = 400°C and P = 5 bar enters the machine. 100 kg/min of saturated liquid water at 40°C leaves the
Steam enters a turbine at 10 bar. The effluent pressure is 1 bar and the efficiency of the turbine is 80%. Determine the state of the turbine effluent (if pure liquid or vapor, find the temperature,
A 10 ounce glass of water (half full) is initially at 15°C. It is left outside overnight in a location where the air temperature is –5°C. By morning the glass is in equilibrium with the
Prove that the process shown in Figure 4-9 is impossible if the cylinder contains a monatomic ideal gas P = 1 bar, T= 300 K P = 1.0 bar T = 300 K l l l l l l l l l P= 1 bar, T = 300 K P = 5.0 bar T =
A stream of liquid nitrogen enters an adiabatic, steady-state valve as a saturated liquid at P = 2 MPa. The material leaves the valve at P = 0.6 MPa. Use the data in Figure 2-3 to determine the
Ten moles of a gas are placed in a rigid container. Initially the gas is at P = 0.5 bar and T = 300 K and the container is also at T = 300 K. The container is placed in a furnace, where its
A 10 kg copper block has an initial temperature of 800 K. It is placed in a well-insulated vessel containing 100 kg of water initially at 290 K. The process is isobaric at atmospheric pressure.
One of the steps in a typical refrigeration process is a boiler. Freon® 22 enters a steady-state boiler as a VLE mixture with a pressure P = 0.5 bar and quality of q = 0.2, and leaves the boiler as
One of the steps in a typical refrigeration process is a compressor. Freon® 22 enters a steady-state compressor as saturated vapor at P = 0.5 bar, and leaves at P = 3 bar. Use the data in Appendix F
One of the steps in a typical refrigeration process is a condenser. Freon® 22 enters a condenser at steady state as superheated vapor at P = 3 bar and T = 30°C. It leaves the condenser as saturated
Four eggs labeled A, B, C, and D are to be placed in three bowls labeled 1, 2, and 3.A. How many distinct “microstates“ are there?B. How many distinct “macrostates” are there? List the
A high-temperature reservoir at T = 500°F is to be used as the heat source for a steady-state heat engine, and a low-temperature reservoir at T = 75°F is to be used as the heat sink. The boiler
You have four molecules labeled 1, 2, 3, and 4 and two bins labeled A and B. Any number of molecules can be placed in each bin.A. List all of the possible microstates. How many are there?B. List all
A high-temperature reservoir at T = 375°C is to be used as the heat source for a steady-state heat engine, and a low-temperature reservoir at T = 25°C is to be used as the heat sink. The boiler
Two chambers are separated by a partition. One of the chambers is evacuated, and the other has a volume of 1 m3 and contains steam at T = 500°C and P = 10 bar. The partition is removed, allowing the
Throughout Chapters 3 and 4, we have assumed that potential and kinetic energy are negligible in standard chemical process equipment. This proble tests how valid these approximations are for turbine.
Saturated liquid water enters a steady-state, adiabatic throttling valve at T = 100°C . The pressure of the fluid leaving the valve is P = 0.5 bar. It has been suggested that perhaps it would make
Superheated steam enters a steady-state, adiabatic throttling valve at T = 200°C and P = 1 bar. The pressure of the fluid leaving the valve is P = 0.5 bar. It has been suggested that perhaps it
The thermostat in a house is set at 70°F. Consequently, the inside of the house is always at 70°F, regardless of the season.A. One day, the outside temperature is 50°F, and the house loses 100 kJ
A nuclear power plant generates 750 MW of power. The heat engine uses a nuclear reactor operating at 315°C as the source of heat. A river is availabl (at~20°C) which has a volumetric flow rate of
The table below contains specifications for five different steady-state Rankine heat engines, A–E. Fill in all the missing data. NOTE: All numbers in the table are given as ABSOLUTE VALUES;
The table below contains specifications for six different steady-state Rankine heat engines, A–F. Fill in all of the missing data. ABU B с D EF F Ĥ Boiler Exit Ĥ Turbine
You are designing a chemical process that involves a relatively unstudied compound, and you need to know Δ Hvap, ΔUvap and ΔSvap, and CP* for the compound at atmospheric pressure. You place 1 mole
The table below contains specifications for six different steady-state vapor-compression refrigerators, A–F. Fill in the missing data. NOTE: All numbers are given as ABSOLUTE VALUES. Determine
The table on the right contains specifications for four different liquefaction processes, A–D, all of which are designed using the basic flow sheet shown in Figure E5-5. Fill in the missing data.
The table below contains specifications for six different steady-state vapor-compression refrigerators, A–F. Fill in all of the missing data. A AB B с D E ப ட Ĥ Boiler
A refrigerator runs on the vapor-compression cycle. The boiler operates at T = 265 K and the condenser operates at 305 K. The compressor has an efficiency of 85%. Thermodynamic data for two different
A schematic of a variation on the Rankine cycle is shown in Figure P5-9—not for steam but for an organic fluid. This process has been called the “organic Rankine cycle”:A. Do some research and
The engine on a steam ship runs on the Rankine cycle. The steam leaves the boiler at 20 bar and 350°C. The turbine has an efficiency of 75% and an outlet pressure of 1 bar. The pressure changes in
A refrigerator runs on the vapor compression cycle, using HFC-134a as a refrigerant. The boiler operates at 20°F. The effluent from the condenser is 10°F above ambient temperature. The compressor
The boiling point of a compound at P = 0.1 MPa is 150 K. The Linde liquefaction process will be used to produce saturated liquid at P = 0.1 MPa, which has a specific enthalpy of 20 kJ/kg. The Table
A heat engine operates on the Rankine cycle, with saturated steam at T = 350°C leaving the boiler, a condenser operating at T = 100°C, and a turbine efficiency of 80%.A. Find the liquid fraction
Water is the most common working fluid in a Rankine heat engine, but there is no fundamental reason why a Rankine heat engine couldn’t be designed with other working fluids. Suppose a heat engine
A steady-state liquefaction process generates 100 lbm/min of saturated liquid methane at P = 10 psia. Fresh methane enters the process at T = 75°F and P = 10 psia, and is mixed with the recycled
A steady-state heat engine operates on the Rankine cycle.∎ The steam entering the turbine is 1 kg/s of steam at P = 3.5 MPa and T = 350°C.∎ The ACTUAL stream exiting the turbine is a mixture of
A refrigeration process operates using the vaporcompression cycle, using a proprietary refrigerant that the inventor claims is better than R-134a. At low pressures, the refrigerant can be assumed to
A steady-state Rankine cycle currently in service operates as follows:∎ Steam leaves the boiler at P = 8 bar and T = 250°C.∎ Steam leaves the turbine as saturated vapor at P = 0.3 bar.∎ Water
You are designing a Rankine heat engine which must produce 10,000 kJ/min of NET shaft work. The heat source is at T = 200°C and the low-temperature reservoir at T= 25°C. The turbine efficiency is
You are designing a steady-state liquefaction process that will manufacture liquid methane. Part A of this problem will focus on two unit operations: the flash separation step itself, and the
You are designing a refrigeration cycle, and have the option of using either a compressor with an efficiency of 70% or a compressor that is more expensive by $5000 but has an efficiency of 80%. The
Find expressions for the residual molar internal energy, residual molar enthalpy, and residual molar entropy for a fluid that is described by each of the following:A. The ideal gas lawB. The
Find expressions for the isothermal compressibility and coefficient of thermal expansion for an ideal gas. Expressions should be in terms of measurable properties only.
Find expressions for the isothermal compressibility and the coefficient of thermal expansion for a fluid that is described by the van der Waals equation of state. Expressions should be in terms of
The system is a 5 lbm object that has CP = 0.1 BTU/ lbm · °R. Find the change in entropy when:A. It is heated reversibly from 500°R to 1000°R.B. It is cooled reversibly from 200°F to 50°F.C. It
The system is 1 kg of nitrogen, initially at T = 300 K and P = 4 bar. For each of the following cases, find the change in entropy of the system using Figure 2-3, then find the change in entropy again
Find the efficiency of each of the following Carnot heat engines.A. TH = 500 K, TC = 300 KB. TH = 500°C, TC = 300°CC. TH = 1000°F, TC = 500°FD. TH = 1000°R, TC = 500°R
For the methanol (1) + acetone (2) system at 101.325 kPa, what is the K-factor for each substance at 332 K? What is the relative volatility at 332 K? Use Figure 10-16.
Calculate the Raoult’s Law predicted vapor-phase composition and bubble-point pressure for an equimolar mixture of methanol (1) + ethanol (2) at 273.15 K. Please report the pressure in bar.
There are four types of VLE calculations for mixtures: A. Bubble-point temperature B. Bubble-point pressure C. Dew-point temperature D. Dew-point pressure For each of the calculations, list the
For the n-pentane (1) + methanol (2) system at 422.6 K (Wilsak et al., 1987), answer the following questions based on Figure P10-13. A. List the boiling point for the pure components ( n-pentane and
The Journal of Chemical and Engineering Data is one journal that publishes, among other items, experimental data for vapor–liquid equilibrium of mixtures. Using the Journal of Chemical and
Consider the 1-hexene (1) + n-hexane (2) system at 328.15 K. Using Raoult’s Law, predict the sys tempressure and vapor-phase composition for this mixture and provide a Pxy plot for this mixture.
Consider the methanol (1) + ethanol (2) system at 101.325 kPa. Using Raoult’s Law, predict the sys tem temperature and vapor-phase composition for this mixture and provide a Txy plot for this
Consider the n-hexane (1) + ethanol (2) system at 1 bar. Using Raoult’s Law, predict the system temperature and vapor-phase composition for this mixture and provide a Txy plot for this mixture.
A new and relatively unstudied compound is being investigated for its potential use as a refrigerant in a vapor compression cycle that operates with T = 25°C in the boiler and T = 35°C in the
A new and relatively unstudied compound is being investigated for potential use as the working fluid in a Rankine heat engine. In the proposed heat engine, the boiler will operate at T = 200°C, with
A compound has Tc = 800 K, Pc = 45 bar, C*P = 8R, and ω = 0.25 and is well modeled by the Peng-Robinson equation of state. 10 mol/s of the compound enters a turbine in the vapor state at T = 600 K
One mole of η-butane vapor is compressed at a constant temperature of 400 K from P = 0.1 bar to P = 15 bar. Using the Peng-Robinson equation of state:A. Find ΔU for the gas in this process.B. Find
Five moles per second of n-butane enter a turbine at P = 15 bar and T = 500 K and leave the turbine at P = 1 bar. The turbine has an efficiency of 80%. Find the rate at which work is done, using the
For a mixture of methyl ethyl ketone (1) + water (2) at 45°C, what would be the predicted bubble-point pressure using Raoult’s Law if your mixture was 20% water by mole? Would you expect
Consider the n-pentane (1) + methanol (2) system at 422.6 K in Figure P10-13. Four numbered black dots are provided on the Pxy diagram, and they are all at 422.6 K. For each of the four points,
Consider the tetrahydrofuran (1) + n-hexane (2) system at 313.15 K. Using Raoult’s Law, predict the system pressure and vapor-phase composition for this mixture and provide a Pxy plot for this
The Lennard-Jones parameters that describe intermolecular interactions for a compound are ε = 1 kJ/ mol and σ = 0.4 nm.A. Determine the intermolecular distance at which potential energy is
Estimate the vapor pressure of benzene at temperatures of T = 0, 50, 100 and 150°C, using the following methods.A. The Antoine equationB. The Clausius-Clapeyron equation with ΔHvap = 33.9 kJ/mol
Estimate the vapor pressure of n-pentane at temperatures of T = 0, 50, 100, and 150°C, using the following methods.A. The Antoine equationB. The Clausius-Clapeyron equation, with ΔHvap = 25.8
Estimate the boiling points of n-hexane at pressures of P = 0.1, 0.5, 1, and 5 bar, using the following methods.A. The Antoine equationB. The Clausius-Clapeyron equation, with ΔHvap = 28.85 kJ/mol
Estimate the boiling points of toluene at pressures of P = 0.1, 0.5, 1, and 5 bar:A. The Antoine equationB. The Clausius-Clapeyron equation, with ΔHvap = 33.2 kJ/mol at the normal boiling point of T
Use the van der Waals EOS to estimate the fugacity of propane at each of the following conditions.A. T = 200 K, P = 0.5 bar (vapor)B. T = 300 K, P = 1 bar (vapor)C. T = 400 K, P = 5 bar (gas)D. T =
Use the Peng-Robinson EOS to estimate the fugacity of butane at each of the following conditions (find both fL and fV if possible).A. T = 300 K, P = 0.5 barB. T = 350 K, P = 5 barC. T = 400 K, P = 1
Use the Peng-Robinson EOS to estimate the fugacity of 1-propanol at each of the following conditions (find both fL and fV if possible).A. T = 300 K, P = 1 barB. T = 300 K, P = 5 barC. T = 400 K, P =
A compound has a liquid molar volume of 0.1 L/mol and a vapor pressure of 0.3 bar at T = 300 K. Estimate the fugacity of this compound in the liquid phase at T = 300 K and each of the following
A compound has a solid molar volume of 85 cm3/mol and at a pressure of 0.25 bar, it sublimates at T = 275 K. Estimate the fugacity of this compound in the solid phase at T = 275 K and each of the
Using only information in the appendices of this book, estimate the boiling points of 1-propanol at pressures of P = 0.1, 0.5, 1, and 5 bar, using the following methods.A. The Antoine equationB. The
Four vapor pressure data points—two representing solid–vapor equilibrium and two representing liquid–vapor equilibrium—are available for a compound:A. Give your best estimate of the triple
Ten moles of a gas is placed in a piston-cylinder device, initially at P = 0.1 bar, and its temperature is maintained constant temperature T = 50°C throughout the following process:∎ The gas is
Ten moles of a solid is placed in a piston-cylinder device, and its pressure is maintained constant at P = 0.7 atm throughout the following process.∎ The solid is heated to 47°C, at which
For each of the following compounds, make a table and graph that compare the vapor pressure vs. temperature predictions obtained from the Antoine and shortcut equations over the entire region 0.5 <
Use the Peng-Robinson EOS to estimate each of the following properties of 1-propanolA. The vapor pressure at T = 100°C.B. The fugacity of saturated vapor at T = 100°C.C. The fugacity of saturated

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