Questions and Answers of Introduction To Chemical Engineering Thermodynamics

Estimate the entropy (J/g-K) of steam at 27.5MPa and 425C.
For each of the states below, calculate the number of moles of ideal gas held in a three liter container.(a) T = 673 K, P = 2 MPa(b) T = 500 K, P = 0.7 MPa(c) T = 450 K, P = 1.5 MPa
A 5 m3 outdoor gas storage tank warms from 10°C to 40°C on a sunny day. If the initial pressure was 0.12 MPa at 10°C, what is the pressure at 40°C, and how many moles of gas are in the tank? Use
An automobile tire has a pressure of 255 kPa (gauge) in the summer when the tire temperature after driving is 50°C. What is the wintertime pressure of the same tire at 0°C if the volume of the tire
A 5 m3 gas storage tank contains methane. The initial temperature and pressure are P = 1 bar, T = 18°C. Using the ideal gas law, calculate the P following each of the successive steps.(a) 1 m3 (at
Calculate the mass density of the following gases at 298 K and 1 bar.(a) Nitrogen(b) Oxygen(c) Air (use average molecular weight)(d) CO2(e) Argon
Calculate the mass of air (in kg) that is contained in a classroom that is 12m x 7m x 3m at 293 K and 0.1 MPa.
Five grams of the specified pure solvent is placed in a variable volume piston. What is the volume of the pure system when 50% and 75% have been evaporated at: (i) 30°C, (ii) 50°C? Use the
A gasoline spill is approximately 4 liters of liquid. What volume of vapor is created at 1 bar and 293 K when the liquid evaporates? The density of regular gasoline can be estimated by treating it as
The gross lifting force of a balloon is given by (ρair – ρgas)Vballoon. What is the gross lifting force (in kg) of a hot air balloon of volume 1.5E6 L, if the balloon contains gas at 100°C and 1
LPG is a useful fuel in rural locations without natural gas pipelines. A leak during the filling of a tank can be extremely dangerous because the vapor is denser than air and drifts to low elevations
The gas phase reaction A → 2R is conducted in a 0.1 m3 spherical tank. The initial temperature and pressure in the tank are 0.05 MPa and 400 K. After species A is 50% reacted, the temperature has
A gas stream entering an absorber is 20 mol% CO2 and 80 mol% air. The flowrate is 1 m3/min at 1 bar and 360 K. When the gas stream exits the absorber, 98% of the incoming CO2 has been absorbed into a
A permeation membrane separates an inlet air stream, F, (79 mol% N2, 21 mol% O2), into a permeate stream, M, and a reject stream, J. The inlet stream conditions are 293 K, 0.5 MPa, and 2 mol/min; the
For water at each of the following states, determine the internal energy and enthalpy using the steam tables. (a) (b) (c) | 0 T(C) 100 550 475 180 P(MPa) 0.01 6.25 7.5 0.7
(a) What size vessel holds 2 kg water at 80°C such that 70% is vapor? What are the pressure and internal energy?(b) A 1.6 m3 vessel holds 2 kg water at 0.2 MPa. What are the quality, temperature,
Determine the temperature, volume, and quality for one kg water under the following conditions:(a) U = 3000 kJ/kg, P = 0.3 MPa(b) U = 2900 kJ/kg, P = 1.7 MPa(c) U = 2500 kJ/kg, P = 0.3 MPa(d) U = 350
Two kg of water exist initially as a vapor and liquid at 90°C in a rigid container of volume 2.42 m3.(a) At what pressure is the system?(b) What is the quality of the system?(c) The temperature of
Three kg of saturated liquid water are to be evaporated at 60°C.(a) At what pressure will this occur at equilibrium?(b) What is the initial volume?(c) What is the system volume when 2 kg have been
The energy balance can be developed for just about any process. Since our goal is to learn how to develop model equations as well as to simply apply them, it is valuable practice to obtain the
Three moles of an ideal gas (with temperature-independent CP = (7/ 2)R, CV = (5/2)R) is contained in a horizontal piston/cylinder arrangement. The piston has an area of 0.1 m2 and mass of 500 g. The
The energy balance can be developed for just about any process. Since our goal is to learn how to develop model equations as well as to simply apply them, it is valuable practice to obtain the
One mole of an ideal gas (Cp = 7R/2) in a closed piston/cylinder is compressed from Ti = 100 K, Pi = 0.1 MPa to Pf = 0.7 MPa by the following pathways. For each pathway, calculate ΔU, ΔH, Q, and
The energy balance can be developed for just about any process. Since our goal is to learn how to develop model equations as well as to simply apply them, it is valuable practice to obtain the
One mole of an ideal gas (Cp = 5R/2) in a closed piston/cylinder is compressed from Ti = 298 K, Pi = 0.1 MPa to Pf = 0.25 MPa by the following pathways. For each pathway, calculate ΔU, ΔH, Q, and
The energy balance can be developed for just about any process. Since our goal is to learn how to develop model equations as well as to simply apply them, it is valuable practice to obtain the
One mole of an ideal gas (Cp=7R/2) in a closed piston/cylinder is expanded from Ti = 700 K, Pi = 0.75 MPa to Pf = 0.1 MPa by the following pathways. For each pathway, calculate ΔU, ΔH, Q, and
The energy balance can be developed for just about any process. Since our goal is to learn how to develop model equations as well as to simply apply them, it is valuable practice to obtain the
One mole of an ideal gas (Cp = 5R/2) in a closed piston/cylinder is expanded from Ti = 500 K, Pi = 0.6 MPa to Pf = 0.1 MPa by the following pathways. For each pathway, calculate ΔU, ΔH, Q, and
The energy balance can be developed for just about any process. Since our goal is to learn how to develop model equations as well as to simply apply them, it is valuable practice to obtain the
(a) What is the enthalpy change needed to change 3 kg of liquid water at 0°C to steam at 0.1 MPa and 150°C?(b) What is the enthalpy change needed to heat 3 kg of water from 0.4 MPa and 0°C to
The energy balance can be developed for just about any process. Since our goal is to learn how to develop model equations as well as to simply apply them, it is valuable practice to obtain the
Steam undergoes a state change from 450°C and 3.5 MPa to 150°C and 0.3 MPa. Determine ΔH and ΔU using the following:(a) Steam table data.(b) Ideal gas assumptions. (Be sure to use the ideal gas
The energy balance can be developed for just about any process. Since our goal is to learn how to develop model equations as well as to simply apply them, it is valuable practice to obtain the
Five grams of the specified pure solvent is placed in a variable volume piston. What are the molar enthalpy and total enthalpy of the pure system when 50% and 75% have been evaporated at: (i)
Create a table of T, U, H for the specified solvent using a reference state of H = 0 for liquid at 25°C and 1 bar. Calculate the table for: (i) Liquid at 25°C and 1 bar; (ii) Saturated liquid at
Consider a block of concrete weighing 1 kg.(a) How far must it fall to change its potential energy by 1 kJ?(b) What would be the value of its velocity at that stage?
A block of copper weighing 0.2 kg with an initial temperature of 400 K is dropped into 4 kg of water initially at 300 K contained in a perfectly insulated tank. The tank is also made of copper and
One kg of methane is contained in a piston/cylinder device at 0.8 MPa and 250°C. It undergoes a reversible isothermal expansion to 0.3 MPa. Methane can be considered an ideal gas under these
In the preceding problem, suppose that the copper block is dropped into the water from a height of 50 m. Assuming no loss of water from the tank, what is the change in internal energy of the block?
One kg of steam in a piston/cylinder device undergoes the following changes of state. Calculate Q and W for each step.(a) Initially at 350 kPa and 250°C, it is cooled at constant pressure to
In the following take CV = 5 and CP = 7 cal/mol-K for nitrogen gas:(a) Five moles of nitrogen at 100 °C is contained in a rigid vessel. How much heat must be added to the system to raise its
In one stroke of a reciprocating compressor, helium is isothermally and reversibly compressed in a piston + cylinder from 298 K and 20 bars to 200 bars. Compute the heat removal and work required.
A rigid cylinder of gaseous hydrogen is heated from 300 K and 1 bar to 400 K. How much heat is added to the gas?
Air at 30°C and 2MPa flows at steady state in a horizontal pipeline with a velocity of 25 m/s. It passes through a throttle valve where the pressure is reduced to 0.3 MPa. The pipe is the same
Saturated steam at 660 °F is adiabatically throttled through a valve to atmospheric pressure in a steady-state flow process. Estimate the outlet quality of the steam.
Refer to Example 2.10 about transformation of kinetic energy to enthalpy. Instead of water, suppose N2 at 1 bar and 298 K was flowing in the pipe. How would that change the answers? In particular,
Argon at 400 K and 50 bar is adiabatically and reversibly expanded to 1 bar through a turbine in a steady process. Compute the outlet temperature and work derived per mole.
Steam at 500 bar and 500°C undergoes a throttling expansion to 1 bar. What will be the temperature of the steam after the expansion? What would be the downstream temperature if the steam were
Steam at 150 bars and 600°C passes through process equipment and emerges at 100 bars and 700°C. There is no flow of work into or out of the equipment, but heat is transferred.(a) Using the steam
An adiabatic turbine expands steam from 500°C and 3.5 MPa to 200°C and 0.3 MPa. If the turbine generates 750 kW, what is the flow rate of steam through the turbine?
A 700 kg piston is initially held in place by a removable latch above a vertical cylinder. The cylinder has an area of 0.1 m2; the volume of the gas within the cylinder initially is 0.1 m3 at a
A steam turbine operates between 500°C and 3.5 MPa to 200°C and 0.3 MPa. If the turbine generates 750 kW and the heat loss is 100 kW, what is the flow rate of steam through the turbine?
A tennis ball machine fires tennis balls at 40 mph. The cylinder of the machine is 1 m long; the installed compressor can reach about 50 psig in a reasonable amount of time. The tennis ball is about
Valves on steam lines are commonly encountered and you should know how they work. For most valves, the change in velocity of the fluid flow is negligible. Apply this principle to solve the following
A 700 kg piston is initially held in place by a removable latch inside a horizontal cylinder. The totally frictionless cylinder (assume no viscous dissipation from the gas also) has an area of 0.1
An overall balance around part of a plant involves three inlets and two outlets which only contain water. All streams are flowing at steady state. The inlets are: 1) liquid at 1MPa, 25°C, ṁ = 54
Steam at 550 kPa and 200°C is throttled through a valve at a flow rate of 15 kg/min to a pressure of 200 kPa. What is the temperature of the steam in the outlet state, and what is the change in
A 0.1 m3 cylinder containing an ideal gas (CP /R = 3.5) is initially at a pressure of 10 bar and a temperature of 300 K. The cylinder is emptied by opening a valve and letting pressure drop to 1 bar.
Dimethyl ether (DME) synthesis provides a simple prototype of many petrochemical processes. Ten tonnes (10,000 kg) per hour of methanol are fed at 25°C. The entire process operates at roughly 10
As part of a supercritical extraction of coal, an initially evacuated cylinder is fed with steam from a line available at 20 MPa and 400°C. What is the temperature in the cylinder immediately after
A large air supply line at 350 K and 0.5 MPa is connected to the inlet of a well-insulated 0.002 m3 tank. The tank has mass flow controllers on the inlet and outlet. The tank is at 300 K and 0.1 MPa.
Two moles of nitrogen are initially at 10 bar and 600 K (state 1) in a horizontal piston/cylinder device. They are expanded adiabatically to 1 bar (state 2). They are then heated at constant volume
A distillation column with a total condenser is shown in Fig. 3.3. The system to be studied in this problem has an average enthalpy of vaporization of 32 kJ/mol, an average CPL of 146 J/mol°-C, and
The Arrhenius model of global warming constitutes a very large composite system. It assumes that a layer of gases in the atmosphere (A) absorbs infrared radiation from the Earth's surface and
Allyl chloride (AC) synthesis provides a simple prototype of many petrochemical processes. 869 kg per hour of propylene (C3) are fed with a 1% excess of chlorine (Cl2) at 25°C. The entire process
Chlorobenzene(l) is produced by reacting benzene(l) initially at 30°C with Cl2(g) initially at 30°C in a batch reactor using AlCl3 as a catalyst. HCl(g) is a by-product. During the course of the
In the process of reactive distillation, a reaction occurs in a distillation column simultaneously with distillation, offering process intensification. Consider a reactive distillation including the
Benzene and benzyl chloride produced from the reaction described in problem 3.6 are separated by distillation at 1 bar. The chlorine and HCl are removed easily and this problem concerns only a binary
This problem considers oxidation of glucose as a model carbohydrate.(a) In the human body glucose is typically metabolized in aqueous solution. Ignoring the enthalpy change due to dissolving glucose
Compressed air at room temperature (295 K) is contained in a 20-L tank at 2 bar. The valve is opened and the tank pressure falls slowly and isothermally to 1.5 bar. The frictionless piston-cylinder
A well-insulated tank contains 1 mole of air at 2 MPa and 673 K. It is connected via a closed valve to an insulated piston/cylinder device that is initially empty. The piston may be assumed to be
A piston/cylinder has two chambers and includes a spring as illustrated below. The righthand side contains air at 20°C and 0.2 MPa. The spring exerts a force to the right of F = 5500x N where x is
We wish to determine the final state for the gas in an inflated balloon. Initially, the balloon has a volume of Vi at rest. The volume of the balloon is related to the internal pressure by V = a·P +
Call placement of a particle in box A, “heads” and placement in box B, “tails.” Given one particle, there are two ways of arranging it, H or T. For two particles, there are four ways of
CO2 is given a lot of credit for global warming because it has vibrational frequencies in the infrared (IR) region that can absorb radiation reflected from the Earth and degrade it into thermal
Twenty molecules are contained in a piston + cylinder at low pressure. The piston moves such that the volume is expanded by a factor of 4 with no work produced of any kind. Compute ΔS/k.
An ideal gas, with temperature-independent CP = (7/2)R, at 15°C and having an initial volume of 60 m3, is heated at constant pressure (P = 0.1013 MPa) to 30°C by transfer of heat from a reservoir
Fifteen molecules are distributed as 9:4:2 between equal-sized boxes A:B:C, respectively. The partitions between the boxes are removed, and the molecules distribute themselves evenly between the
Steam undergoes a state change from 450°C and 3.5 MPa to 150°C and 0.3 MPa. Determine ΔH and ΔS using the following:(a) Steam table data(b) Ideal gas assumptions (be sure to use the ideal gas
The following problems involve one mole of an ideal monatomic gas, CP = 5R/2, in a variable volume piston/cylinder with a stirring paddle, an electric heater, and a cooling coil through which
Rolling two die (six-sided cubes with numbers between 1 and 6 on each side) is like putting two particles in six boxes. Compute ΔS /k for going from double sixes to a four and three.
Estimate the change in entropy when one mole of nitrogen is compressed by a piston in a cylinder from 300 K and 23 liters/mol to 400 K and 460 liters/mol. (CP = 7/2R)
When a compressed gas storage tank fails, the resultant explosion occurs so rapidly that the gas cloud can be considered adiabatic and assumed to not mix appreciably with the surrounding atmosphere.
Steam at 400°C and 10 bar is left in an insulated 10 m3 cylinder. The cylinder has a small leak, however. Compute the conditions of the steam after the pressure has dropped to 1 bar. What is the
Work problem 4.5 but consider a steam boiler that fails. The boiler is 250 L in size, operating at 4 MPa, and half full of liquid.Data from problem 4.5When a compressed gas storage tank fails, the
A mixture of 1CO:2H2 is adiabatically and continuously compressed from 5 atm and 100°F to 100 atm and 1100°F. For this mixture, CP = x1CP1 + x2CP2.(a) Estimate the work of compressing 1 ton/h of
An isolated chamber with rigid walls is divided into two equal compartments, one containing gas at 600 K and 1 MPa and the other evacuated. The partition between the two compartments ruptures.
An adiabatic compressor is used to continuously compress nitrogen (CP /R = 7/2) from 2 bar and 300 K to 15 bar. The compressed nitrogen is found to have an outlet temperature of 625 K. How much work
An isolated chamber is divided into two equal compartments, one containing gas and the other evacuated. The partition between the two compartments ruptures. At the end of the process, the temperature
An adiabatic compressor is used to continuously compress low-pressure steam from 0.8 MPa and 200°C to 4.0 MPa and 500°C in a steady-state process. What is the work required per kg of steam through
Airplanes are launched from aircraft carriers by means of a steam catapult. The catapult is a well-insulated cylinder that contains steam, and is fitted with a frictionless piston. The piston is
An adiabatic turbine is supplied with steam at 2.0 MPa and 600°C and the steam exhausts at 98% quality and 24°C. Compute the work output per kg of steam. Compute the efficiency of the turbine.
We have considered heat and work to be path-dependent. However, if all heat transfer with surroundings is performed using a reversible heat transfer device (some type of reversible Carnot-type
An adiabatic compressor has been designed to continuously compress 1 kg/s of saturated vapor steam from 1 bar to 100 bar and 1100°C. Estimate the power requirement of this compressor in horsepower.
Consider the wintertime heating of a house with a furnace compared to addition of Carnot heat engines/pumps. To compensate for heat losses to the surroundings, the house is maintained at a constant
Ethylene gas is to be continuously compressed from an initial state of 1 bar and 20°C to a final pressure of 18 bar in an adiabatic compressor. If compression is 70% efficient compared with an
An ideal gas enters a valve at 500 K and 3 MPa at a steady-state rate of 3 mol/min. It is throttled to 0.5 MPa. What is the rate of entropy generation? Is the process irreversible?
Operating a wind tunnel for aircraft experiments begins with adiabatically and reversibly compressing atmospheric air (300 K) into long cylinders comprising a total volume of 20 m3 at 200 bars. The
SO2 vapor enters a heat exchanger at 100°C and at a flowrate of 45 mole/h. If heat is transferred to the SO2 at a rate of 1,300 kJ/h, what is the rate of entropy transport in the gas at the outlet

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