Description

Chapter: 2 -Problem: 9 >> Sketch two isotherms on a P–v plot for an ideal gas. Label each, taking T2 > T1.
Answer Preview: In an ideal gas the relationship between pressure P volume v and tempera…

, Chapter: 5 -Problem: 90 >> As a fluid flows steadily past a turbine blade with friction present, the fluid velocity drops from 400 m/s to 100 m/s while the fluid enthalpy increases by 25 kJ/kg. Assuming the process ais adiabatic, determine the specific work transfer (kJ/kg) from the fluid to the blade.
Answer Preview: ANSWER Since the process is adiabatic there is no he…

, Chapter: 12 -Problem: 74 >> Create a spreadsheet model of a turbojet combustor in which the air temperature, fuel temperature, and air–fuel ratio are input quantities, and the combustion product temperature is an output quantity. Use iso-octane (C8H18) and simple air as the reactants.
Answer Preview: In this exercise the input quantities are the air temperature in Ke…

, Chapter: 11 -Problem: 14 >> At state 1, a piston–cylinder device contains 0.004m3 of moist air initially at 20° C and 0.10135MPa with a 70% relative humidity. The volume is then decreased to 0.002m3 at state 2 as the piston is pushed inward in a reversible isothermal process. A. Complete the following table: B. Does the total internal energy of the contents of the cylinder increase, decrease, or remain constant during this
Answer Preview: ANSWER A To complete the table we need to calculate the properties at states 1 and 2 Given data Initial volume state …

, Chapter: 1 -Problem: 14 >> Consider an automobile, containing a driver and several passengers, traveling along a country road. Isolate the automobile and its contents from the surroundings by drawing an appropriate boundary. Does your boundary enclose a thermodynamic closed system or an open system? Justify your choice by writing a sentence or two. How would you have to modify your boundary  convert from one to the other? W
Answer Preview: To isolate the automobile and its contents from the surroundings we can draw a boundary that encloses the car and its occupants but not the air outsid…

, Chapter: 5 -Problem: 54 >> Steam (13.2 kg) at 1.5 MPa with an 80% quality comprises a thermodynamic system. The steam is heated in a frictionless process until the temperature is 540 K.A. Calculate the heat transfer (kJ) if the process occurs at constant pressure.B. What is the heat transfer if the process is carried out at constant volume?
Answer Preview: ANSWER To solve this problem we will use the First Law of Thermodynamics which states that the chang…

, Chapter: 12 -Problem: 48 >> Determine the heat transfer in the constant-volume combustion of 1 kg of carbon indicated in the following reaction: The reactants are at 298 K and the products are at 500 K. Transcribed Image Text: C + 1.5 0? CO2 + 0.5 0?.
Answer Preview: The given chemical equation for the combustion of carbon can be written as C 1 5O2 CO2 0 5O2 The sto…

, Chapter: 12 -Problem: 11 >> For correct operation of the catalytic converter in an automobile, the air–fuel ratio of the engine must be precisely controlled to near the stoichiometric value. This control is achieved using feedback from an O2 sensor located in the exhaust stream. A. If the equivalent composition of gasoline is given by C8H15, determine the value of the stoichiometric air–fuel ratio (by mass). Assume that air
Answer Preview: A To determine the stoichiometric airfuel ratio we need to find the mole ratio of air to fuel requir…

, Chapter: 1 -Problem: 5 >> Consider the toy balloon shown in Fig. 1.22. (a) Define an open system that is different than the one illustrated in the figure. Write a sentence describing your choice and draw a sketch for each indicating your boundary with a dashed line. (b) Define two closed systems associated with the balloon/air system. Write a sentence describing each of your choices and draw a sketch for each, indicating y
Answer Preview: Using Figure 1 22 An open system can be drawn to include only the air in the ball…

, Chapter: 5 -Problem: 72 >> Consider the following four (A–D) closed thermodynamic systems at an instant. The systems consist of a single-phase substance.Answer the questions posed for the following scenarios:A. At a particular instant, energy enters a system as a heat interaction at a rate of 14 kJ/s. No energy leaves. Is the rate  change of the system energy positive, negative, or zero? Give the numerical value. Is the sys
Answer Preview: Answer A Since energy is entering the system as a heat interaction at a rate of 14 kJ s and no energ…

, Chapter: 13 -Problem: 37 >> Hydrogen and oxygen react to form water. Determine the equilibrium composition (mole fractions) at 4000 K and 1 atm of an initial mixture of 1 kmol of hydrogen (H2) and 1 kmol of oxygen (O2).
Answer Preview: The balanced chemical equation for the reaction of hydrogen and oxygen to form water is 2H2 O2 2H2O …

, Chapter: 11 -Problem: 33 >> As shown in the sketch below, moist air enters an insulated tube at station 1with properties T1, P1, and ?1. Moisture is added to the air stream as it passes through a wick and exits at station 2 saturated with moisture (i.e., ?2 = 100%) at a temperature T2. The pressure at station 2 can be assumed to be the same as at station 1. The make-up water is supplied to the wick as saturated liquid, also
Answer Preview: ANSWER To derive an expression for calculating the specific humidity 1 at station 1 we can use the c…

, Chapter: 1 -Problem: 15 >> Write out the formal definitions of the following terms: property, state, and process. What is the relationship of a property to a state? What is the relationship of a state to a process? What is the relationship of a property to a process?
Answer Preview: Property A property is a characteristic of a substance or system that can be measured and quantified …

, Chapter: 5 -Problem: 52 >> Saturated steam is contained in a sealed rigid tank at 500 K (state 1). Energy is removed from the steam by heat transfer until a temperature of 350 K (state 2) is reached. Determine the heat transfer.
Answer Preview: To determine the heat transfer we need to use the first law of thermodynamic…

, Chapter: 13 -Problem: 38 >> Nitric oxide (NO) is a major pollutant formed in high-temperature combustion processes, but typically in less than equilibrium amounts. Equilibrium values thus can be considered to be upper limits. For the equilibrium reaction N2 + O2 ? 2 NO determine the equilibrium partial pressures and the mole fractions (in parts per million) of the nitric oxide at combustion-like conditions of 2200 K and 10 a
Answer Preview: The equilibrium constant for the reaction N2 O2 2NO is given by Kp pNO pN2 pO2 where pNO pN2 and pO2 …

, Chapter: 12 -Problem: 3 >> Distinguish between the terms “rich” and “lean.”
Answer Preview: The terms rich and lean can have different meanings depending on the context in which they are used …

, Chapter: 2 -Problem: 14 >> Write out a physical interpretation of the thermodynamic property “quality”.
Answer Preview: In thermodynamics quality is a property that describes the degree to which a substance is a vapor or …

, Chapter: 5 -Problem: 53 >> Consider a piston–cylinder assembly containing 0.12 kg of superheated steam at 700 kPa and 800 K (state 1). Energy is removed from the steam by heat transfer until a temperature of 400 K is reached (state 2). The process is conducted at constant pressure. Determine the work and heat transfer.
Answer Preview: To determine the work and heat transfer during the process we can apply the first law of thermodynam…

, Chapter: 12 -Problem: 69 >> Air enters a turbojet engine with a velocity of 150m/s (at station 1) and a mass flow rate of 23.6 kg/s. Fuel is supplied to the engine at 0.3165 kg/s. The mass specific standardized enthalpy of the air and fuel are 1.872 kJ/kgA and –3210.4 kJ/kgF, respectively, and the standardized enthalpy of the combustion products exiting the engine is –129.9 kJ/kge. Estimate the thrust developed by the engine
Answer Preview: To estimate the thrust developed by the turbojet engine we need to use the principle of conservation …

, Chapter: 3 -Problem: 75 >> A cylindrical water tank, shown in the sketch, has a cross-sectional area of 5m2. Water flows out of the tank through a pipe of 0.2-m diameter with an average velocity V1 of 6 m/s. Water flows into the tank through a 0.1m diameter pipe with an average velocity V2 of 12 m/s. Define an open system (control volume) and determine the rate at which the water level rises in the tank. Use a formal mass c
Answer Preview: ANSWER To analyze the rate at which the water level rises in the cylindrical tank we can define an open system or control volume around the tank The c…

, Chapter: 11 -Problem: 3 >> Sketch an air conditioner. Discuss its operation.
Answer Preview: Description An air conditioner also known as an AC or air conditioning system is a device that regulates the temperature humidity and air quality with…

, Chapter: 8 -Problem: 43 >> The compressor at the inlet section of a jet engine has a diameter of 4 ft and receives air at 730 ft/s and 20 F. The air is compressed reversibly and adiabatically from 4 to 36 psia. The discharge velocity is negligible. Determine the horsepower required to operate the compressor.
Answer Preview: To determine the horsepower required to operate the compressor we can use the following equation Pow…

, Chapter: 1 -Problem: 66 >> Determine the indefinite integral of y(x) where Transcribed Image Text: y(x) = 19.86-597x-0.5 + 7500/x.
Answer Preview: 19 86 597x05 75…

, Chapter: 8 -Problem: 64 >> Using your computer solution from Problem 8.63, vary the outflow pressure from 300 kPa to 6 MPa. Plot the  power as a function of the outflow pressure. Put pressure on the abscissa (x-axis) of the plot. Problem 8.63Solve Problem 8.62 using EES or other software.Problem 8.62Determine the power required to is entropically pump 25 kg/s of water from saturated liquid at 50 kPa to 3.0 MPa. Assume incom
Answer Preview: To plot the power as a function of the outflow pressure we first need to determine the power require…

, Chapter: 13 -Problem: 57 >> Ammonia is used as a refrigerant in large-scale refrigeration systems. Using data for ammonia (NH3) from the NIST resources, verify that the condition for phase equilibrium (Eqs.13.35) is met. Use temperatures of 300 and 400 K. Transcribed Image Text: [Nf (8£ - 88), dGsys=0= dNf8f
Answer Preview: The condition for phase equilibrium can be expressed as G 0 or G sys n R R G where G sys is the chan…

, Chapter: 4 -Problem: 11 >> A 3.0-kg steel projectile is fired from a gun. At a particular point in its trajectory it has a velocity of 300 m/s, an altitude of 700 m, and a temperature of 350 K. The projectile is spinning about its longitudinal axis at an angular speed of 100 rad/s. Treating the projectile as a thermodynamic system, calculate the total system energy relative to a reference state of zero velocity, zero altitu
Answer Preview: To calculate the total energy of the system we need to consider the kinetic energy KE potential energy PE and internal energy U of the projectile The …

,

, Chapter: 8 -Problem: 9 >> List several devices that can act as throttles.
Answer Preview: Several devices that can act as throttl…

, Chapter: 1 -Problem: 27 >> Consider the following statement: For a quasi equilibrium process, the property changes can be large, e.g., the final pressure can be much larger (or greater) then the initial pressure. Is this statement true or false? Explain your choice.
Answer Preview: True In a quasi equilibrium process there can be changes …

, Chapter: 8 -Problem: 58 >> Water flowing at 950,000 liters/min enters a pump in a power plant at 150° C and 0.5 MPa. The pump increases the water pressure to 10 MPa (v = 0.063 m3/kg).Determine (a) The mass flow rate (kg/hr), (b) The volume flow rate at discharge (liters/min), (c) The temperature change across the pump (°C), (d) The enthalpy change across the pump (kJ/kg).
Answer Preview: To solve this problem we will use the conservation of mass and energy principles along with the properties of water at different conditions …

, Chapter: 13 -Problem: 20 >> Consider the reaction N2 ? 2 N. Determine a numerical value for the equilibrium constant Kp for the reaction as written for temperatures of 500 K and 5000 K. Compare your results with Problem 13.19 and discuss. Problem 13.19In a steam reforming process, natural gas (or other hydrocarbon or coal) is used to produce hydrogen. In this process, the water–gas shift equilibrium reaction H2O + CO ? CO2 +
Answer Preview: To determine the numerical value for the equilibrium constant Kp for the reaction N2 2 N at temperat…

, Chapter: 3 -Problem: 39 >> A gas enters a steady-flow system through a 5-cm-diameter tapering duct with an average velocity of 3.5 m/s and a density of 1.20 kg/m3. It leaves the duct with a specific volume of 0.31m3 /kg through a 1.6-cm-diameter constriction. Determine (a) The mass flow rate (kg/hr) (b) The average outlet velocity (m/s).
Answer Preview: To determine the mass flow rate and the average outlet velocity we can use the principle of conserva…

, Chapter: 11 -Problem: 1 >> Sketch an evaporative cooler. Discuss its operation.
Answer Preview: An evaporative cooler also known as a swamp cooler works on the principle of evaporative cooling which is the process of cooling air by the evaporatio…

, Chapter: 7 -Problem: 117 >> A Carnot heat engine receives 633 kJ from a reservoir at 650° C while rejecting heat at 38° C. Determine the work delivered (kJ) and the engine efficiency. Also determine the entropy change (kJ/K) associated with the high- and low temperature reservoirs.
Answer Preview: The Carnot efficiency of a heat engine is given by 1 T cold T hot where T hot is the absolute temper…

, Chapter: 1 -Problem: 38 >> The National Ambient Air Quality Standard (NAAQS) for lead (Pb) in the air is 1.5 ?g/m3. Convert this standard to US customary units of lbm/ft3.
Answer Preview: To convert the NAAQS for lead from g m3 to lbm ft3 we need to use the followin…

, Chapter: 5 -Problem: 58 >> An 2.27-m3 steam boiler initially contains 1.7025m3  of liquid water and 0.5675m3 of water vapor in equilibrium at 100 kPa. The boiler is fired up and the liquid and vapor in the boiler are heated. Somehow the valves on the inlet and discharge of the boiler are both left closed. The relief valve lifts when the pressure reaches 4.0 MPa. Determine the heat transfer (kJ) to the boiler before the reli
Answer Preview: Answer To solve this problem we need to apply the First Law of Thermodynamics which states that the change in internal energy of a system is equal to the heat added to the system minus the work done b…

, Chapter: 13 -Problem: 61 >> Determine the number of degrees of freedom associated with the following systems. Also, use the NIST resources, and any other resources you can find, to determine numerical values associated with the pressure and temperature boundaries (lines, regions, point) associated with each system.A. Liquid CO2B. Vapor CO2C. Liquid and solid CO2D. Liquid and vapor CO2E. Solid and vapor CO2F. Solid, liquid, a
Answer Preview: The number of degrees of freedom DOF for a system is given by the number of independent intensive variables required to specify the state of the system The intensive variables are those that are indep…

, Chapter: 4 -Problem: 21 >> Consider an ideal gas contained in a piston–cylinder arrangement as a closed thermodynamic system. The gas expands following a polytropic process PVn = P1Vn1 from state 1 to state 2. The polytropic exponent n is a constant.A. Starting with the definition of moving-boundary work ? Pdv derive an expression to evaluate the work in terms of the pressures and volumes at the  initial and final states.B.
Answer Preview: A The definition of moving boundary work is given by the equation Work P dv To evaluate the work in …

, Chapter: 11 -Problem: 8 >> Define the humidity ratio, ?.
Answer Preview: The humidity ratio denoted as is a fundamental property used to describe the amount of mo…

, Chapter: 1 -Problem: 1 >> Write out the definition of thermodynamics. Using this definition as a guide, list three practical situations or devices that closely relate to thermodynamics. Explain the relationships of each situation/device to thermodynamics. Do not repeat any of the examples given in book.
Answer Preview: Definition of Thermodynamics Thermodynamics is the science that deals with the relationship of he…

, Chapter: 5 -Problem: 49 >> Saturated steam is contained in a sealed rigid tank at 600 K (state 1). Energy is removed from the steam by heat transfer until a temperature of 400 K (state 2) is reached. Plot the process in P–v and T–v coordinates. Include the steam dome on your plots. Determine the following quantities for this process: 1W2/M, ?u, ?h, and 1Q2/M.
Answer Preview: Given Constant temperature expansion of nitrogen Find Heat transfer for …

, Chapter: 2 -Problem: 76 >> In a closed (fixed-mass) system, an ideal gas undergoes a process from an initial state with pressure 517 kPa and volume of 0.1416m3 to a final state with pressure 172.3 kPa and volume of 0.2741m3. For this process, the enthalpy change ?H is –65.4 kJ and the average constant-volume specific heat cv,avg is 3.157 kJ/kg·K. Determine:(a) The internal energy change ?U.(b) The average constant-pressure
Answer Preview: Given a b c P 517 …

, Chapter: 3 -Problem: 38 >> Air with a density of 1.20 kg/m3 enters a steady-flow control volume through a 0.3-m-diameter duct with an average velocity of 3 m/s. The air leaves with a specific volume of 0.311 m3/kg through a 0.1-m diameter duct. Determine (a) The mass flow rate (kg/hr) (b) The average outlet velocity (m/s).
Answer Preview: To determine the mass flow rate and the average outlet velocity of the air we can use the principle …

, Chapter: 11 -Problem: 19 >> Combustion products (10% carbon dioxide, 20% water vapor, and 70% nitrogen, by volume) enter a pipe at 200 F and 14.7 psia. The mass flow rate of the products is 6 lbm/min. The products are cooled as they flow through the pipe and leave at 100 F and 14.7 psia. Determine (a) The mass flow rate (lbm/min) of water condensed(b) The heat-transfer rate (Btu/min).
Answer Preview: To solve this problem we need to use the energy balance equation and the ideal gas law Here are the steps to solve the problem Step 1 Calculate the ma…

, Chapter: 5 -Problem: 80 >> Which of the following are true statements? Justify your responses, true or false, with a sentence or two.cA. Enthalpy appears in the conservation of energy equation for open systems because open systems involve constant-pressure processes.B. Enthalpy appears in the conservation-of-energy equation for ope systems because the internal energies of the inlet and outlet fluid streams are negligible.C.
Answer Preview: ANSWER A True Enthalpy appears in the conservation of energy equation for open systems because open …

, Chapter: 12 -Problem: 32 >> One mole of a hydrocarbon fuel (CHx) is burned with excess air. The volumetric analysis of the dry products (with H2O removed) yields: A. Determine the approximate composition of the fuel on a mass basis.B. Determine the percent theoretical air.C. Determine the equivalence ratio. Transcribed Image Text:
Answer Preview: A To determine the approximate composition of the fuel on a mass basis we need to do a mass balance on the carbon and hydrogen in the fuel Since we do…

, Chapter: 4 -Problem: 32 >> Initially, 0.05 kg of air is contained in a piston–cylinder device at 200° C and 1.6MPa. The air then expands at constant temperature to a pressure of 0.4 MPa. Assume the process occurs slowly enough that the acceleration of the piston can be neglected. The ambient pressure is 101.35 kPa. A. Determine the work (kJ) performed by the air in the cylinder on the piston. B. Determine the work (kJ) per
Answer Preview: To solve this question we use first law of thermodynamics which states that the change in internal energy of a system is equal to the heat added to th…

, Chapter: 11 -Problem: 64 >> In a classroom the temperature is 78 F, the adiabatic saturation temperature is 64 F, and the barometric pressure is 29.175 in Hg.A. Determine the humidity ratio.B. Determine the partial pressures (in Hg) of the dry air and of the water vapor.C. Determine the relative humidity.D. Determine the density (lbm,mix/ft3).E. Determine the dew-point temperature.
Answer Preview: To solve this problem we will use psychrometric charts and equations Psychrometry is the study of the properties of air and water vapor mixture Given Room temperature 78 F Adiabatic saturation tempera…

, Chapter: 5 -Problem: 44 >> Initially, 1 kg of air at 101 kPa and 700 K is contained in a rigid tank. The tank is not insulated and cools down, as  result of heat transfer to the atmosphere (Tatm = 25° C, Patm = 101 kPa), until it reaches thermal equilibrium. Determine the final pressure (kPa) and the heat transfer (kJ) for the process.
Answer Preview: ANSWER This problem can be solved using the ideal gas law …

, Chapter: 13 -Problem: 59 >> Consider the liquid–vapor equilibrium of H2O at 20° C in which N2 is added to the gas phase to obtain a total pressure of 1 atm. Assuming that the N2 is both inert and insoluble in the liquid H2O, how does the N2 affect the equilibrium pressure (or partial pressure) of the H2O vapor? To answer this, compute the partial pressure of the H2O vapor in the H2O(g)–N2 mixture. The total pressure is fixed
Answer Preview: Since N2 is inert and insoluble in the liquid H2O it does not affect the equili…

, Chapter: 4 -Problem: 64 >> The torque in the shaft of a water pump is 15 N·m. How much work is performed after 1000 revolutions of the shaft?
Answer Preview: Given Rotating drive shaft wit…

, Chapter: 11 -Problem: 5 >> Sketch a cooling tower. Discuss its operation.
Answer Preview: A cooling tower is a large cylindrical or box like structure that is commonly found in industrial settings particularly in power plants refineries and …

, Chapter: 8 -Problem: 88 >> Steam with a flow rate of 65 kg/s enters an isentropic turbine at 12 MPa and exits at 70 kPa. Using your computer solution from Problem 8.87, vary the inflow temperature from 500° C to 650° C. Plot the turbine power as a function of the inflow temperature. Put temperature on the abscissa (x-axis) of the plot. Problem 8.87Solve Problem 8.86 using EES or other software. Problem 8.86Steam at 600° C a
Answer Preview: To solve Problem 8 86 we can use the steam tables to determine the properties of steam at the given …

, Chapter: 12 -Problem: 25 >> Rework Problem 12.24 but use propane as the fuel. Problem 12.24Ethane burns with 150% stoichiometric air. Assume the air is 79% N2 and 21%O2 by volume. Combustion goes to completion. Determine (a) The air–fuel ratio by mass (b) The mole fraction (percentage) of each product.
Answer Preview: To solve this problem we can start by writing the balanced chemical equation for the combustion of p…

, Chapter: 3 -Problem: 22 >> Air at 540°C and 140 KPa flows through a 2-ft-inside-diameter pipe at a mass flow rate of 1.05 kg/s. Determine the average velocity (m/s) of the air. Assume ideal-gas behavior.
Answer Preview: To determine the average velocity of air flowing through a pipe we can use the equation v m dot A wh…

, Chapter: 11 -Problem: 63 >> The temperature and adiabatic saturation temperature for a room of moist air are measured to be 30° C and 20° C, respectively.A. Determine the humidity ratio and relative humidity if the pressure is 1 atm.B. Determine the humidity ratio if the pressure is 0.95 atm with the same temperature and adiabatic saturation temperature as in Part A.
Answer Preview: To solve this problem we need to use the psychrometric chart which is a graphical representation of the thermodynamic properties of moist air We will …

, Chapter: 5 -Problem: 24 >> Consider a piston–cylinder assembly containing 0.12 kg of nitrogen initially at 700 K and 300 kPa (state 1). The piston moves such that the final volume of the nitrogen (state 2) is three times larger than the initial volume (state 1). The process occurs at constant temperature. Plot the process on P–v and T–v coordinates. Assuming a constant value of the constant-pressure specific heat of 1.067 k
Answer Preview: Since the process occurs at constant temperature we can assume that the nitrogen undergoes an isothe…

, Chapter: 13 -Problem: 35 >> Carbon monoxide and water react to form carbon dioxide and hydrogen (H2), the so-called water-gas shift reaction. Determine the equilibrium composition (mole fractions) of a mixture at 1100 K and 1 atm initially containing 1 kmol of carbon monoxide and 1 kmol of water.
Answer Preview: The balanced chemical equation for the water gas shift reaction is CO g H2O g CO2 g H2 g At equilibr…

, Chapter: 4 -Problem: 8 >> Initially, 1 lbm of water is at rest at 14.7 psia and 70 F. The water then undergoes a process where the final state is 30 psia and 700 F with a velocity of 100 ft/s and an elevation of 100 ft above the starting location. Determine the increases in internal energy, potential energy, and kinetic energy of the water in Btu/lbm. Compare the increases in potential energy and kinetic energy individuall
Answer Preview: To solve this problem we will use the first law of thermodynamics which states that the change in internal energy of a system is equal to the amount o…

, Chapter: 10 -Problem: 23 >> A 5-m3 tank contains 2 kmol of oxygen and 5 kmol of nitrogen at 300 K.a. Find the total pressure of the mixture.b. Find the apparent constant-volume specific heat using a mass-basis  (cv,mix in kJ/kg · K) and molar-basis (cv,mix in kJ/kg · K).c. Find the heat transfer required to raise the temperature of the mixture to 500 K using the apparent specific heat from part b. Assume that the apparent sp
Answer Preview: a To find the total pressure of the mixture we can use the ideal gas law PV nRT where P is the pressure V is the volume n is the number of moles R is the gas constant and T is the temperature First we …

, Chapter: 8 -Problem: 90 >> In the production of orange juice, it is desired to heat the juice from 4° C to 93° C in a tubular heat exchanger. To accomplish this task, saturated steam enters the outer tube of the heat exchanger at 150 kPa and exits as a saturated liquid at the same pressure. For an orange juice flow rate of 2000 kg/hr (c?p = 3.9 kJ/kg·K), determine the required steam flow rate.
Answer Preview: We can use the energy balance equation for the heat exchanger to determine the steam …

, Chapter: 12 -Problem: 34 >> Derive that (x + y/4)/? is the oxidizer coefficient a in the combustion reaction where ? is the air–fuel equivalence ratio. Start by considering the case where ? = 1; i.e., by doing C, H, O, and N balances you get a = x + y/4 when the mixture is in stoichiometric proportions. Then show how ? enters in when the mixture is not stoichiometric.
Answer Preview: When the mixture is in stoichiometric proportions the balanced equation for the combustion reaction is CxHy O2 3 76N2 xCO2 y 2 H2O 3 76xN2 3 76y 4N2 w…

, Chapter: 9 -Problem: 109 >> Consider the air-standard Otto cycle described in Problem 9.94, operating with a compression ratio of 8:1. In the constant-volume heat-addition process (state 2–state 3), 1800 kJ/kg of energy is transferred to the air. If the cycle begins with air at ambient conditions of 100 kPa and 15° C (state 1), determine the cycle efficiency. Also determine the heat rejected to the atmosphere. Problem 9.941-
Answer Preview: To determine the cycle efficiency and the heat rejected to the atmosphere in the air standard Otto c…

, Chapter: 11 -Problem: 1 >> For the purpose of testing air conditioners, the following indoor and outside air temperatures and relative humidities are defined for a so-called moderate climate: Determine the specific humidity and dew point associated with these two conditions. Transcribed Image Text: Indoors: Outside: TA 27 °C
Answer Preview: To determine the specific humidity and dew point associated with the given indoor and outdoor condit…

, Chapter: 5 -Problem: 69 >> A small propane tank (V = 0.0185 m3), used to fuel a barbeque grill, is approximately half full and contains 10 pounds (4.55 kg) of propane. A fire breaks out enveloping the tank in flames. There is no pressure relief system to prevent the pressure from building up as the tank heats. If the pressure in the tank reaches 1000 psia (6.89 MPa), there is a good chance that the tank will rupture. How mu
Answer Preview: ANSWER To calculate the energy required to reach the pressure of 1000 psia we need to use the ideal …

, Chapter: 13 -Problem: 23 >> Consider the reaction N2 + O2 , 2 NO. Determine a numerical value for the equilibrium constant Kp for the reaction as written for temperatures of 1000 K and 3500 K. Discuss
Answer Preview: To determine the numerical value of the equilibrium constant Kp for the reaction N2 O2 2 NO at diffe…

, Chapter: 2 -Problem: 18 >> A pressure gage connected to a compressed air tank reads 325 kPa. The local barometric pressure reading is 28.3 inches of mercury. Calculate the absolute pressure in units of psia, psfa (pounds-force per square foot absolute), and atm.
Answer Preview: Conversion factors given in text inside front cove…

, Chapter: 4 -Problem: 12 >> Consider a 25-mm-diameter steel ball that has a density of 7870 kg/m3 and a constant-volume specific heat of the form What velocity would the ball have to achieve so that its bulk kinetic energy equals its internal energy at 500 K? Use an internal energy reference. state of 300 K. Transcribed Image Text:
Answer Preview: To solve this problem we need to use the principle of conservation of energy The bulk kinetic energy …

, Chapter: 12 -Problem: 2 >> Determine whether the following mixtures are stoichiometric: Transcribed Image Text: A. B. C?H? + 40? C8H18 + 120?
Answer Preview: To determine if a mixture is stoichiometric we need to compare the ratio of the actual number o…

, Chapter: 5 -Problem: 91 >> An ideal gas passes steadily through a device that increases the gas velocity from 5m/s to 300 m/s without transfer of heat or work.A. Determine the increase in specific enthalpy (kJ/kg) of the gas.B. If the specific heat of the gas is a linear function of temperature given by cp [kJ/kg · K] = 1.00 + 0.01T [K], determine the increase in temperature of the gas if it enters the device at 20°C.
Answer Preview: ANSWER To solve this problem we will use the first law of thermodynamics which states that the change in the internal energy of a system is equal to t…

, Chapter: 12 -Problem: 22 >> Natural gas is burned to produce hot water to heat a clothing store. Assuming that the natural gas can be approximated as methane (CH4) and that the air is a simple mixture of O2 and N2 in molar proportions of 1:3.76, determine the following:A. The molar air–fuel ratio for stoichiometric combustion.B. The mass air–fuel ratio for stoichiometric conditions.C. The operating air–fuel ratio (mass) of t
Answer Preview: The balanced equation for the combustion of methane can be written as CH4 2 O2 3 76N2 CO2 2H2O 7 52N2 A The molar airfuel ratio for stoichiometric com…

,

, Chapter: 3 -Problem: 43 >> A variable-diameter duct has a flow cross-sectional area of 0.006m2 at state 1 and 0.002m2 at state 2. Steam at 680 K and 6.0 MPa enters at state 1 at a velocity of 30 m/s, flows steadily through the duct, and leaves at 580 K and 3.0MPa at state 2. (a) Determine the velocity (m/s) at state 2, (b) Use the NIST software to plot the 6.0 and 3.0 MPa isobars on a T–v plot and indicate the inlet and out
Answer Preview: a To determine the velocity at state 2 we can apply the principle of conservation of mass In a stead…

, Chapter: 11 -Problem: 29 >> An evaporative cooler inducts outside air at 46° C (114.8 F) and 100 kPa having a relative humidity of 16%. The air is cooled to 29° C (84.2 F). Determine the following quantities: A. The mass of water added by the cooler per unit mass of dry air. B. The relative humidity of the outlet stream. C. The mass and volumetric flow rates of the added water when the volumetric flow rate of the entering mo
Answer Preview: A The mass of water added per unit mass of dry air can be calculated using the psychrometric chart or equations From the given conditions the initial …

, Chapter: 1 -Problem: 9 >> From your list in Problem 1.2, select two devices, or parts of those devices, that you can represent as closed systems. Sketch each device, show the system boundary as a dotted line, and label as needed to make your sketch intelligible. Discuss why your  choice encloses a closed system. Problem 1.2 Transcribed Image Text:
Answer Preview: Clothes iron Electric…

, Chapter: 5 -Problem: 85 >> Show in excruciating detail that the units associated with the term V2/2 are J/kg.
Answer Preview: The term V 2 2 often appears in the context of kinetic energy which is the energy that an object pos…

, Chapter: 13 -Problem: 65 >> Methanol has been proposed for use in fuel cells for automotive applications. The vapor pressure for methanol (CH3OH) was measured to be 4.02 and 352 kPa at 273 K and 373 K, repectively. Use these data to estimate the enthalpy of vaporization (kJ/kg) of methanol. Compare your result with the actual value (from the NIST resources or other source) at the average of the two temperatures.
Answer Preview: To estimate the enthalpy of vaporization of methanol we can use the Clausius …

, Chapter: 2 -Problem: 125 >> A piston–cylinder arrangement contains 0.05 m3 of liquid water and 2.0 m3 of water vapor in equilibrium at 1.5 MPa. Heat crosses the boundary from the surroundings to the H2O at constant pressure until the temperature reaches 700 K. Use tables, not the NIST software, to solve this problem.A. Sketch the process in both T–v and P–v coordinates. B. Determine the initial temperature of the H2O. C. Det
Answer Preview: ANSWER A Sketch the process in both T v and P v coordinates In T v coordinates the process can be represented by a horizontal line on the superheated …

, Chapter: 2 -Problem: 152 >> Determine (a) The specific enthalpy of evaporation of steam (kJ/kg) (b) The ratio of the vapor to liquid specific volumes at standard atmospheric pressure.
Answer Preview: To determine the specific enthalpy of evaporation of steam and the ratio of vapor to liquid specific …

, Chapter: 11 -Problem: 20 >> Moist natural gas enters a valve at 40° C, 0.2 MPa, and 70% relative humidity with a volumetric flow rate of 20m3/min. An analysis of the dry gases in the natural gas shows 80% methane and 20% hydrogen by volume as the gas enters. The moist natural gas leaves the valve at 0.15 MPa. Determine the moisture condensation rate (kg/min).
Answer Preview: Given the conditions of moist natural gas entering a valve we can determine the moisture condensatio…

, Chapter: 2 -Problem: 10 >> Sketch two isobars on a T– v plot for an ideal gas. Label each, taking P2 > P1.
Answer Preview: Sure here is a sketch of two isobars on a T v plot …

, Chapter: 8 -Problem: 78 >> A turbine receives steam at a pressure of 1000 psia and 1000 F and exhausts the steam at 3 psia. The velocity of the steam at the inlet is 50 ft/s. At the outlet, which is 10 ft higher, the velocity is 1000 ft/s. Assuming that the operation is reversible and adiabatic, determine the work produced per unit mass. Transcribed
Answer Preview: Assuming that the turbine operation is reversible and adiabatic we can apply the steady flow energy …

, Chapter: 12 -Problem: 54 >> Determine the mass of CO2 produced (kg) per unit of energy released (kJ), i.e., the CO2 emission, for the complete combustion of the following fuels. The higher heating value (HHV) expresses the energy released per mass of fuel burned. Transcribed Image Text: Fuel Methane Natural gas Gasoline Diesel
Answer Preview: To calculate the CO2 emission factor we need to use the equation CO2 emission factor kg CO2 kg fuel …

, Chapter: 2 -Problem: 27 >> A cylinder containing a gas is fitted with a piston (see the above sketch). The cross-sectional area of the piston is 0.029m2. Assume that there is no frictional force at the piston–cylinder wall interface. The atmospheric pressure is 0.1035 MPa and the acceleration due to gravity is 30.1 ft/s2. To produce an absolute pressure in the gas of 0.1517 MPa, what mass (kg) of the piston is required?
Answer Preview: Given 4 0 029 m Convert the gravitational 1 m g 30 1 ft s 3 2808 ft The gag…

,

, Chapter: 11 -Problem: 18 >> A1-kg mixture of air and water vapor at 20 °C, 1 atm, and 75% relative humidity is confined in a cylinder by a frictionless piston. This mixture is compressed isothermally until the pressure is 2 atm. Determine (a) The final relative humidity and humidity ratio.(b) The mass (kg) of water vapor condensed.
Answer Preview: To solve this problem we can use the psychrometric chart which relates the properties of moist air such as relative humidity humidity ratio temperatur…

, Chapter: 1 -Problem: 16 >> Can you identify any devices that operate in a thermodynamic cycle? If so, list them. Also, identify the working fluids, if known.
Answer Preview: Yes there are several devices that operate in a thermodynamic cycle Here are a few examples 1 Refrig…

, Chapter: 5 -Problem: 83 >> Repeat Problem 5.82, eliminating the assumption of a steady state. Problem 5.82Without reference to the text, write a symbolic expression for the conservation of energy (the first law of thermodynamics) for a open system having a single inlet and a single outlet. Assume steady state. Below each term, write its meaning in words.
Answer Preview: The conservation of energy for an open system with a single inle…

, Chapter: 2 -Problem: 128 >> Water at 10.0 MPa (absolute) is heated from 350 K to 380 K. Determine the change in mass-specific enthalpy for this process in three ways. (1) Use the tables in Appendix B, interpolating as required. (2) Use the NIST software or online database. (3) Use the liquid property approximation, Eqn. 2.41c. Compare your results and discuss. Eqn. 2.41c.
Answer Preview: We will solve the problem in three ways as instructed Solution 1 Using Tables in Appendix B From the …

, Chapter: 2 -Problem: 102 >> Carbon dioxide (CO2) is heated in a constant-pressure process from 15° C and 101.3 kPa to 86° C. Determine, per unit mass, the changes in:(a) Enthalpy(b) Internal energy(c) VolumeAll in SI units. Use the NIST software or online database to find these quantities.
Answer Preview: Analysis a b c Given Constant pressure process of carbon diox…

, Chapter: 4 -Problem: 24 >> A polytropic process is one that obeys the relationship PVn = constant, where n may take on various values. A. Define the type of process associated with each of the following values of n, assuming the working fluid is an ideal gas (i.e., determine which state variable is constant): B. Starting from the same initial state, which process results in the most amount of work performed by the gas when
Answer Preview: A The type of process associated with each of the following values of n assuming the working fluid i…

, Chapter: 11 -Problem: 34 >> Moist air enters an air conditioner at 305.3 K, 137.9 kPa, and 80% relative humidity. The mass flow rate of dry air entering is 45.4 kg/min. The moist air leaves the air conditioner at 285.3 K, 124.1 kPa, and 100% relative humidity. The condensed moisture leaves at 285.3 K and 124.1 kPa. Determine the heat transfer rate (kW) from the moist air.
Answer Preview: To solve this problem we need to use the psychrometric chart to determine the properties of the mois…

, Chapter: 1 -Problem: 53 >> Vigorous swimming results in the “burning” of 11 food calories per minute. What is amount of energy associated with 30 minutes  swimming expressed in Btu? How many equivalent ounces (mass of gasoline are associated with this energy expenditure? An approximate value for the energy density of gasoline is 20,000 Btu per pound-mass. One food calorie (or large calorie) is equivalent to 4184 joules. One
Answer Preview: Conversions Energy rate 1 food calorie 4184 J …

, Chapter: 5 -Problem: 45 >> Air, initially at 205°C and 3.45 MPa, expands isothermally in a piston–cylinder device until its volume is 100 times larger than its initial volume. Determine the following:A. The increase in internal energy (kJ/kg) of the airB. The work transfer (kJ/kg) and direction into or out of the air.C. The heat transfer (kJ/kg) and direction into or out of the air.
Answer Preview: To solve this problem we can use the ideal gas …

, Chapter: 12 -Problem: 16 >> An automobile is traveling at 55 mph on a highway. The car’s engine is operating at 2000 revolutions per minute. The engine fills its cylinders with air each time two revolutions are completed, i.e., it operates on a four-stroke cycle. The volume of air ingested during each cycle is 95% of the engine’s displacement of 1.5 liters. The air enters the cylinders at 0.7 atm and 305 K. Determine the fol
Answer Preview: A The volumetric flow rate of the air at the entering conditions is calculated using the ideal gas law PV nRT where P 0 7 atm V 1 5 L x 0 95 1 425 L 0 …

, Chapter: 2 -Problem: 99 >> Use the van der Waals equation of state to determine the density of propane (C3H8) at 400 K and 12.75 MPa. How does this value compare with that obtained from the NIST software or online database?
Answer Preview: Given Propane P 12 75 MPa T 400 K Properties The molecular weight for propane is found from …

, Chapter: 9 -Problem: 103 >> Express the thermal efficiency of a Carnot-cycle heat engine in terms of the isentropic compression ratio (Vrisen ? Vlarge/Vsmall).
Answer Preview: The thermal efficiency of a Carnot cycle heat engine can be expressed in terms of the isentropic com…

, Chapter: 11 -Problem: 7 >> Define the term “psychrometry.” How is psychrometry included in a weather report?
Answer Preview: Psychrometry is a branch of science that deals with the study of the physical and thermodynamic properties of air and water vapor mixtures particularl…

, Chapter: 1 -Problem: 39 >> The astronauts of Apollo 17, the final US manned mission to the moon, collected 741 lunar rock and soil samples, having a  mass of 111 kg. Determine the weight of samples in SI and US customary units (a) on the lunar surface (gmoon = 1.62 m/s2) and (b) on the earth (gearth = 9.807 m/s2). Also determine (c) the mass of the samples in US customary units.
Answer Preview: a To find the weight of the lunar rock and soil samples on the lunar surface we can use the formula …

, Chapter: 5 -Problem: 50 >> Consider a piston–cylinder assembly containing 0.125 kg of wet steam with a quality of 0.45 at 300 kPa (state 1). Energy is added to the steam at constant temperature by a heat interaction until the volume of the steam is doubled (state 2). Determine the heat transfer. Give units.
Answer Preview: To determine the heat transfer in this process we need to use the first law of thermodynamics U Q W …

,

, Chapter: 10 -Problem: 3 >> On a hot (95 F) summer day the relative humidity reaches an uncomfortable 85%. At this condition, the water vapor mole fraction is 0.056. Treating the moist air as an ideal-gas mixture of water vapor and dry air, determine the mass fraction of water vapor and the apparent molecular weight of the moist air. Treat the dry air as a simple substance with a molecular weight of 28.97 kg/kmol.
Answer Preview: To determine the mass fraction of water vapor we need to use the mole fraction and the molecular wei…

, Chapter: 11 -Problem: 4 >> Combustion products (10% carbon dioxide, 20% water vapor, and 70% nitrogen by volume) flow in a pipe at 94° C and 1.36 atm. Determine (a) The dew-point temperature (°C)(b) The humidity ratio(c) The relative humidity.
Answer Preview: To determine the dew point temperature humidity ratio and relative humidity we need additional infor…

, Chapter: 1 -Problem: 6 >> Turn on a faucet and observe the stream of water flowing from it. Define a closed system related to the water in this situation. How do the boundaries change and move with time? What would you  to do to change your closed system to an open system?
Answer Preview: A closed system shown as the solid red box tha…

, Chapter: 5 -Problem: 81 >> Write out in words the precise meaning of the following symbols. Be very specific, using appropriate adjectives as needed. Also provide the usual SI units associated with the quantities. If the quantity is dimensionless, write “dimensionless.” For the terms that are products of symbols, give a single word or short phrase describing the grouping (see example).
Answer Preview: ANSWER A There is no symbol mentioned in the question B Q represents the flow rate which is the quan…

, Chapter: 13 -Problem: 10 >> Consider one kmol of O2 at 2400 K. Calculate and plot the Gibbs function of the O2 for pressures of 0.1, 1.0, 10, and 100 atm.
Answer Preview: To calculate the Gibbs function of O2 at different pressures we can use the Gibbs Helmholtz equation …

, Chapter: 9 -Problem: 132 >> Repeat Problem 9.131 using EES. Find the coefficient of performance and generate T–s diagrams for the original cycle conditions and your two modified cycles having an improved coefficient of performance. Problem 9.131In a vapor-compression refrigeration cycle that circulates R-134a at a rate of 5 kg/min, the refrigerant enters the compressor at –10° C and 0.18 MPa and leaves at 70° C and 0.7 MPa.
Answer Preview: To solve this problem using Engineering Equation Solver EES we need to define the properties of R 134a and set up the refrigeration cycle Unfortunatel…

, Chapter: 11 -Problem: 9 >> Define the relative humidity, ?.
Answer Preview: Relative humidity is the ratio of the amount of water vapor present in …

, Chapter: 1 -Problem: 23 >> Consider the following statement: In a thermodynamic cycle, many but not all, of the thermodynamics properties of the working fluid will be the same at the start and the end of the cycle. Is this statement true or false? Explain your choice.
Answer Preview: False A thermodynamic cycle is a series of proces…

, Chapter: 5 -Problem: 33 >> Consider a piston–cylinder assembly containing 0.10 kg of N2 initially at 425 K and 150 kPa (state 1). The piston moves such that the final pressure of the air is 350 kPa. The process occurs at constant temperature. Determine the magnitude of the heat interaction associated with this process. Indicate the direction of the heat interaction (into or out of the system).
Answer Preview: Since the process is occurring at constant temperature it is isothermal and we can use the following …

, Chapter: 12 -Problem: 66 >> Consider the theoretical combustion of methane in a steady-flow process at 1 atm. Determine the heat transfer per kmol and per kg of fuel from the combustion chamber for the following cases:A. The products and the reactants are at the same temperature of 15.6° C.B. The air and the methane enter at 5° C and 60° C, respectively, and the products exit at 449° C.
Answer Preview: To solve this problem we need to use the first law of thermodynamics which states that the change in internal energy of a system is equal to the heat added minus the work done on the system For a stea…

, Chapter: 4 -Problem: 31 >> A 0.0065-kg mass of air expands in a piston–cylinder assembly following a constant-pressure path with a work output of 1.3 kJ. The initial specific volume of the air is 0.25 m3/kg. The final volume is three times that of the initial volume.A. Sketch the process in P–V and T–V coordinates.B. Determine the gas pressure during the process.C. Determine the initial and final temperatures of the air.
Answer Preview: A In the P V coordinate system the process is represented by a horizontal line at the initial pressu…

, Chapter: 9 -Problem: 99 >> Consider the air-standard diesel cycle described in Problem 9.95 operating with a compression ratio of 15 (= Vmax/Vmin). The air just prior to compression is at 20° C and 0.1014 MPa. The maximum cycle temperature is 2500 K. Assuming constant specific heats, determine the temperature and pressure at the beginning of each process and the thermal efficiency for the cycle. Problem 9.95Consider a fixed
Answer Preview: To solve this problem we need to determine the temperature and pressure at each state of the air standard diesel cycle and calculate the thermal effic…

, Chapter: 1 -Problem: 20 >> List the conditions that must be established for thermodynamic equilibrium to prevail (i.e., list the subtypes of equilibrium).
Answer Preview: Thermodynamic equilibrium is the state variables that do not change with …

, Chapter: 5 -Problem: 78 >> A car battery is charged by applying a current of 40A at 12 V for 30 min. During the charging process, there is a heat transfer of 200  from the battery to the surroundings. Determine the increase in internal energy (Btu) of the battery.
Answer Preview: To determine the increase in internal energy of the battery we need to use the first law of thermody…

, Chapter: 13 -Problem: 62 >> Derive the Clausius–Clapeyron equation from the Clapeyron equation, assuming that the gas-phase specific volume is much, much greater than that of the liquid phase, and that the pressure is sufficiently low that the vapor behaves as an ideal gas.
Answer Preview: The Clapeyron equation relates the vapor pressure of a substance to its enthalpy of vaporization the …

, Chapter: 9 -Problem: 70 >> The cycle shown in the sketch is used to cool the passenger cabin of a commercial aircraft. Air is the working fluid. Assuming an ideal compression process, determine the following:  A. The net work required (hp) per ton of refrigeration (1 ton = 12,000 Btu/hr) B. The heat rejected at the heat exchanger (Btu/hr) C. The turbine isentropic efficiency (%) D. The coefficient of performance
Answer Preview: To solve the problem we ll need to apply the principles of thermodynamics and use the given information Let s go through each part step by step A The …

, Chapter: 12 -Problem: 9 >> Propane reacts completely with a stoichiometric amount of hydrogen peroxide (H2O2) to form carbon dioxide and water. Determine the mass of water formed per mass of propane.
Answer Preview: To determine the mass of water formed per mass of propane we need to calculate the sto…

, Chapter: 1 -Problem: 31 >> Consider a closed system consisting of ice and liquid water. The ice is melting at constant temperature. Is the ice–water system in equilibrium? Explain your answer. Is the ice–water system undergoing a process? Explain your answer.
Answer Preview: Yes ice and liquid water can occur as a m…

, Chapter: 8 -Problem: 84 >> A high-speed turbine produces 1 hp while operating on compressed air. The inlet and outlet conditions are 70 psia and 85 F and 14.7 psia and –50 F, respectively. Assume changes in kinetic and potential energies are negligible. Determine the mass flow rate.
Answer Preview: ANSWER To solve this problem we need to apply the First Law of Thermodynamics which states that the …

, Chapter: 12 -Problem: 37 >> Determine the standardized enthalpies of the following pure species at 4 atm and 2500 K: H2, H2O, and OH.
Answer Preview: To determine the standardized enthalpies of the pure species at 4 atm and 2500 K we need to use the …

,

, Chapter: 11 -Problem: 58 >> An air–water vapor mixture at 14.7 psia, 85 F, and 50% relative humidity is contained in a 15-ft3 tank. At what temperature will condensation begin? If the tank and mixture are cooled an additional 15 F, how much water will condense from the mixture?
Answer Preview: To determine at what temperature condensation will begin we need to find the dew point temperature of the air water vapor mixture This can be done usi…

, Chapter: 7 -Problem: 54 >> Is the adiabatic expansion of superheated steam from 850° C and 2.0 MPa to 650° C and 1.2 MPa possible? Explain.
Answer Preview: To determine if the adiabatic expansion of superheated steam from 850C and 2 0 MPa to 650C and 1 2 M…

, Chapter: 2 -Problem: 13 >> What is the physical significance of the critical point? Locate the critical point on a P–v diagram.
Answer Preview: The critical point in thermodynamics is a condition of a substance where the boundary between the li…

, Chapter: 8 -Problem: 53 >> A compressor uses air as the working fluid. The air enters at 101 kPa and 16° C and exits at 1.86 MPa and 775° C. What is the compressor isentropic efficiency?
Answer Preview: To determine the compressor isentropic efficiency we need to first find the compressor work and then …

, Chapter: 12 -Problem: 40 >> A mixture of products of combustion contains the following constituents at 2000 K: 3 kmol of CO2, 4 kmol of H2O, and 18.8 kmol of N2. Determine the following quantities:A. The mole fraction of each constituent in the mixtureB. The total standardized enthalpy H of the mixtureC. The mass-specific standardized enthalpy h of the mixture
Answer Preview: To solve this problem we need to use the principle of conservation of mass and the thermodynamic pro…

, Chapter: 4 -Problem: 67 >> Determine all the combinations of the following 120-volt kitchen appliances that can be operated simultaneously without tripping a 15-ampere circuit breaker: blender (300 W); clock radio (70 W); coffee maker (1200 W); food processor (200 W); microwave oven (1450 W); toaster oven (1150 W). Would you recommend having more than one 15-amp circuit to accommodate these appliances? Would you recommend a
Answer Preview: To determine which combinations of appliances can be operated simultaneously without tripping a 15 ampere circuit breaker we need to first calculate t…

, Chapter: 12 -Problem: 4 >> A mass of particular solid fuel (70% carbon, 20%hydrogen, and 10% water by mass) reacts stoichiometrically with air. Assume that the air is 79% N2 and 21% O2 by volume. Determine the balanced chemical equation. Your final equation should be for an amount of fuel containing 1 mol of carbon.
Answer Preview: The balanced chemical equation for the combustion of a hydrocarbon fuel with air can be represented …

, Chapter: 7 -Problem: 104 >> In the cylinders of a steam engine, superheated vapor is compressed reversibly from 300 kPa and 460 K to 500 kPa. Calculate the work per unit mass if the process is (a) Adiabatic (b) Isothermal. For each case, sketch the process on P–V and T–s diagrams, showing the vapor dome. On the P–V diagram, include constant temperature curves through the initial and final states. On the T–s diagram, include
Answer Preview: To solve this problem we need to use the equations for reversible adiabatic and isothermal processes a Adiabatic process For an adiabatic process we h…

, Chapter: 1 -Problem: 41 >> The astronauts of Apollo 17, the final US manned mission to the moon, collected 741 lunar rock and soil samples, having a  mass of 111 kg. Determine the weight of samples in SI and US customary units (a) on the lunar surface (gmoon = 1.62 m/s2) and (b) on the earth (gearth = 9.807 m/s2). Also determine (c) the mass of the samples in US customary units.
Answer Preview: a To determine the weight of the lunar rock and soil samples on the lunar surface we need to multipl…

, Chapter: 8 -Problem: 60 >> Solve Problem 8.59 using EES or other software. Problem 8.59Air enters a multistage compressor of a jet engine at 50 kPa and 270 K with a flow rate of 40 kg/s. The compressor has an overall pressure ratio of 20:1. Determine the power required to drive the compressor and the temperature of the air at the compressor outlet. Use the following specific heat at the average temperature:cp = 1.021 kJ/kg·
Answer Preview: To determine the power required to drive the compressor we can use the equation for compressor power …

, Chapter: 12 -Problem: 44 >> A mixture of 5 g of ethane and a stoichiometric amount of oxygen is contained in a piston–cylinder device at 25° C and 1 atm. The piston moves freely without friction. A spark ignites the mixture and a complete reaction occurs at a pressure of 1 atm. The products are cooled to 25° C by the end of the reaction. Determine the following:A. The initial volume (cm3) of the reactantsB. The masses of liq
Answer Preview: First we need to balance the reaction equation for the combustion of ethane C2H6 3 5O2 2CO2 3H2O A To find the initial volume of the reactants we can …

, Chapter: 3 -Problem: 80 >> Water with a density of 990 kg/m3 is flowing through a 3-cm diameter pipe at a mass flow rate of 5 kg/s. What is the flow velocity in the pipe? a. 7.1 m/s,b. 1.8 m/s, c. 22.4 m/s, d. 0.21 m/s.
Answer Preview: To determine the flow velocity in the pipe we can use the equatio…

, Chapter: 12 -Problem: 2 >> What does it mean that a fuel burns with air in stoichiometric proportions?
Answer Preview: When a fuel burns with air in stoichiometric proportions it means that the exact amount of air neede…

, Chapter: 7 -Problem: 33 >> For a simple compressible substance with cp = a(1 + bT), where a and b are constants, determine the entropy change for an isobaric process going from T1 and T2.
Answer Preview: For an isobaric process the pressure is constant and we can use the fol…

, Chapter: 1 -Problem: 36 >> The 1964 Pontiac GTO was one of the first so-called muscle cars produced in the United States in the 1960s and 1970s. The 389-in3 displacement V-8 engine in the GTO delivered a maximum  of 348 hp and a maximum torque of 428 lbf .ft. From a standing start, the GTO traveled 1/4 mile in 14.8 s, accelerating to 95 mph. Convert all the US customary units in these specifications to SI units.
Answer Preview: 1 in 0 0254 m inch to meter 1 ft 0 3048 m foot to meter …

, Chapter: 8 -Problem: 68 >> Steam expands in an ideal adiabatic turbine from 5000 kPa and 400°C to 40 kPa. Determine the turbine power output if the steam is supplied at a rate of 136 kg/s.
Answer Preview: To determine the turbine power output we need to use the First Law of Thermodynamics which states th…

, Chapter: