GERAF REVIEW NOTESPrepared by: Gerry Lou Quiles, CSA-BChemical Engineering Thermodynamics 11. Consider a fish swimming 5 m below the free surface of water. The increase in the pressure exerted on the fish when it dives to a depth of 45 m below the free surface is-a. 392 Pa b. 9800 Pa c. 50,000 Pad. 392,000 Pa2. An apple loses 4.5 kJ of heat as it cools per C drop in its temperature. The amount of heat loss from the apple per F drop in its temperature is-a. 1.25 kJ b. 2.50 kJ c. 5.0 kJ d. 8.1 kJ3. A 2-kW electric resistance heater in a room is turned on and kept on for 30 min. The amount of energy transferred to the room by the heater is-a. 1 kJb. 60 kJ c. 1800 kJ d. 3600 kJ4. In a hot summer day, the air in a well-sealed room is circulated by a 0.50-hp (shaft) fan driven by a 65% efficient motor. (Note that the motor delivers 0.50 hp of net shaft power to the fan). The rate of energy supply from the fan-motor assembly to the room isa. 0.769 kJ/s b. 0.325 kJ/s c. 0.574 kJ/s d. 0.373 kJ/s5. A fan is to accelerate quiescent air to a velocity to 12 m/s at a rate of 3 m3/s. If the density of air is 1.15 kg/m3, the minimum power that must be supplied to the fan is-a. 248 W b. 72 W c. 497 W d. 216 W6. The elevator of a large building is to raise a net mass of 400 kg at a constant speed of 12 m/s using an electric motor. Minimum power rating of the motor should be-a. 0 kW b. 4.8 kW c. 47 kW d. 12 kW7. Electric power is to be generated in a hydroelectric power plant that receives water at a rate of 70 m3/s from an elevation of 65 m using a turbinegenerator with an efficiency of 85 percent. When frictional losses in piping are disregarded, the electric power output of this plant is-a. 3.9 MW b. 38 MW c. 45 MW d. 53 MW8. A 75 hp (shaft) compressor in a facility that operates at full load for 2500 hours a year is powered by an electric motor that has an efficiency of 88 percent. If the unit cost of electricity is P0.06/kWh, the annual electricity cost of this compressor is-a. P 7382 b. P9900 c. P12,780 d. P95369. Ten centimeter high and twenty centimeter wide circuit board houses on its surface 100 closely spaced chips, each generating heat at a rate of 0.08 W and transferring it by convection to the surrounding air at 40C. Heat transfer from the back surface of the board is negligible. If the convection heat transfer coefficient on the surface of the board is 10 W/m2 C and radiation heat transfer is negligible, the average surface temperature of the chips is-a. 80C b. 54C c. 41C d. 72C10. If two objects are in thermal equilibrium with each other-a. they cannot be movingb. they cannot be undergoing an elastic collisionc. they cannot have different pressuresd. they cannot be at different temperatures11. A "closed system" is also known as-a. Control massb. isolated systemc. control volume d. control boundary12. Properties that are independent of the size of the system, such as temperature, pressure, and the density are called-a. intensive propertiesc. extensive propertiesb. extrinsive propertiesd. extrinsic properties13. A H-S diagram is also known as-a. Argand diagramb. Euler diagramc. Mollier diagram d. Grolier diagram14. The condition in which there is no change in pressure at any point of the system with time.a. Thermal equilibriumc. mechanical equilibriumb. Phase equilibriumd. chemical equilibrium

15. A process during which, the specific volume V remains constant is called-a. Isometricb. isovolumetricc. isochoricd. all of these16. Who wrote the first thermodynamics textbook in 1859?a. Lord Kelvinb. William Rankinec. Thomas Young d. Rudolph Clausius17. The area under the process curve on a P-V diagram represents the boundary-a. Temperatureb. pressurec. energy d. work18. A device that increases the pressure of a fluid by slowing it down is called-a. Noozleb. diffuserc. manometer d. heat exchanger19. A rigid tank contains 6 kg of an ideal gas at 3 atm and 40C. Now a valve is opened, and half of mass of the gas is allowed to escape. If the final pressure in the tank is 2.2 atm, the final temperature in the tank is-a. 186C b. 59C c. -43C d. 20C20. Water is boiling at 1 atm pressure in a stainless steel pan on an electric range. It is observed that 2 kg of liquid water evaporates in 30 minutes. The rate of heat transfer to the water is-a. 2.51 kW b. 2.32 kW c. 2.97 kW d. 0.47 kW21. A rigid 3-m3 rigid vessel contains steam at 10 MPa and 500C. The mass of the steam is-a. 3.0 kg b. 19 kg c. 84 kg d. 31 kg22. A certain humidifier operates by raising water to the boiling point and then evaporating it. Every minute 30 g of water at 20 C are added to replace the 30 g that are evaporated. The heat of fusion of water is 333 kJ/kg, the heat of vaporization is 2256 kJ/kg, and the specific heat is 4190 J/kg K. How many joules of energy per minute does this humidifier require?a. 3.0 104b. 8.8 104c. 7.8 104d. 1.1 10523. A system undergoes an adiabatic process in which its internal energy increases by 20 J. Which of the following statements is true?a. 20 J of work was done on the system c. the system received 20 J of energy as heatb. 20 J of work was done by the system d. the system lost 20 J of energy as heat24. A frictionless piston-cylinder device and a rigid tank contain 2 kmol of an ideal gas at the same temperature, pressure and volume. Now heat is transferred, and the temperature of both systems is raised by 10C. The amount of extra heat that must be supplied to the gas in the cylinder that is maintained at constant pressure is-a. 0 kJ b. 42 kJ c. 83 kJ d. 166 kJ25. A 3-m3 rigid tank contains nitrogen gas at 500 kPa and 300 K. Now heat is transferred to the nitrogen in the tank and the pressure of nitrogen rises to 800 kPa. The work done during this process is-a. 500 kJ b. 1500 kJ c. 0 kJ d. 900 kJ26. ChE GATE PROBLEM 2011. One mole of methane is contained in a leak proof piston cylinder assembly at 8 bar and 1000 K. The gas undergoes isothermal expansion to 4 bar under reversible conditions. Methane can be considered as an ideal gas under these conditions. The heat transferred in kJ during the process is-a. 11.52b. 5.76c. 4.15d. 2.3827. Equations of state for a single component can be any of the following, except:a. the ideal gas law, PV= RTb. the ideal gas law modified by insertion of a compressibility factor, PV = ZRT.c. any relationship interrelating 3 or more state functions.d. a mathematical expression defining a path between states.28. The state of a thermodynamic system is always defined by its-a. absolute temperatureb. processc. properties d. temperature and pressure29. Mathematically, a thermodynamic property is which of the following?a. a point functionc. an inexact differentialb. a path functiond. discontinuous30. PIChE National Quiz Bee 2007. Three moles of an ideal gas at 1 atm and 20 OC are heated at constant pressure until the final temperature is 80 OC. (Cv = 7.5 + 3.2 x 10-2 T, cal/ mol K). The change in the internal energy of the process isa. 3210.5 cal b. 2105.3 calc. 2015.3 cald. 1203.5 cal31. A 0.8-m3 cylinder contains nitrogen gas at 600 kPa and 300 K. Now the gas is compressed isothermally to a volume of 0.1 m3. The work done on the gas during this compression process is-a. 746 kJ b. 0 kJ c. 420 kJ d. 998 kJ32. An ordinary egg with a mass of 0.1 kg and a specific heat of 3.32 kJ/kg-C is dropped into boiling water at 95C. If the initial temperature of the egg is 5C, the maximum amount of heat transfer to the egg is-a. 12 kJ b. 30 kJ c. 24 kJ d. 18 kJ33. A pistoncylinder device contains an ideal gas. The gas undergoes two successive cooling processes by rejecting heat to the surroundings. First the gas is cooled at constant pressure until T2 = T1. Then the piston is held stationary while the gas is further cooled to T3 = T1, where all temperatures are in K. The ratio of the final volume to the initial volume of the gas is-a. 0.25 b. 0.50 c. 0.67 d. 0.7534. From problem #33, The work done on the gas by the piston is-a. RT1/4 b. Cv T1/2c. Cp T1/2 d. (Cv+Cp)T1/435. From problem #33, The total heat transferred from the gas is-a. RT1/4 b. CvT1/2 c. CpT1/2d. (Cv+Cp)T1/436. MRII Question. An adiabatic tank contains 20 kg of water. A 220V, 0.1A motor drives a paddle wheel and runs for 45 minutes. Determine the change in the total energy of the system.a. 59.4 kJb. 55.6 kJc. 52.4 kJd. 62.3 kJ37. MRII Question. It is the heat effect accompanying a change in phase at constant temperature.a. sensible heatc. heat capacityb. latent heatd. heat of formation38. Steam enters a diffuser steadily at 0.5 MPa, 300C, and 122 m/s at a rate of 3.5 kg/s. The inlet area of the diffuser is-a. 15 cm2 b. 50 cm2 c. 105 cm2 d. 150 cm239. Water flows through a constriction in a horizontal pipe. As it enters the constriction, the waters:a. speed increases and pressure decreasesc. speed increases and pressure increasesb. speed increases and pressure is constant d. speed decreases and pressure increases40. A heat engine-a. converts heat input to an equivalent amount of work b. converts work to an equivalent amount of heat c. takes heat in, does work, and loses energy heatd. uses positive work done on the system to transfer heat from a low temperature reservoir to a high temperature reservoir41. A heat engine that in each cycle does positive work and loses energy as heat, with no heat energy input, would violate-a. the zeroth law of thermodynamicsc. the second law of thermodynamicsb. the first law of thermodynamics d. the third law of thermodynamics42. A Carnot cycle-a. is bounded by two isotherms and two adiabats on a p-V graphb. consists of two isothermal and two constant volume processesc. is any four sided process on a p-V graphd. only exists for an ideal gas43. The change in entropy is zero for:a. reversible adiabatic processes c. reversible processes during which no work is doneb. reversible isothermal processes d. reversible isobaric processes44. Which of the following processes leads to a change in entropy of zero for the system undergoing the process?a. Non-cyclic isobaric (constant pressure) c. Non-cyclic isothermal (constant temperature)b. Non-cyclic isochoric (constant volume) d. Any closed cycle45. An ideal gas expands into a vacuum in a rigid vessel. As a result there is:a. a change in entropyc. a change in temperatureb. an increase of pressured. a decrease of internal energy46. A copper block (Cp = 0.398 kJ/kg K) having a mass of 15 kg and a temperature of 500 K is placed in a well insulated vessel containing 100 kg of water initially at 300 K. The entropy change in this process (in kJ/kg) is-a. 0.912 b. 3.906c. 2.994d. 6.52147. MRII Question. According to ___________, it is impossible to create a device in which the only effect is to transfer heat from low temperature to high temperature.a. Kelvin Planckb. Clausius c. Carnotd. Clapeyron48. Air at 20C and 5 atm is throttled by a valve to 2 atm. If the valve is adiabatic and the change in kinetic energy is negligible, the exit temperature of air will be-a. 10Cb. 14C c. 17C d. 20C49. The drinking water needs of an office are met by cooling tab water in a refrigerated water fountain from 23C to 6C at an average rate of 10 kg/h. If the COP of this refrigerator is 3.1, the required power input to this refrigerator is-a. 197 Wb. 612 W c. 64 W d. 109 W50. Throttling process is a/an __________ process.a. reversible and isothermalc. reversible and constant enthalpyb. reversible and constant entropyd. irreversible and constant enthalpy51. In case of an __________ process, the temperature of the system increases.a. adiabatic compressionc. isothermal expansionb. isothermal compression d. adiabatic expansion52. The third law of thermodynamics states that the-a. heat capacity of a crystalline solid is zero at absolute zero temperature.b. heat transfer from low temperature to high temperature source is not possible without external work.c. gases having same reduced properties behave similarly.d. none of these.53. The main feature of Carnot refrigeration cycle is that, it-a. accomplishes the reverse effect of the heat engine.b. does not need the addition of external work for its functioning.c. transfers heat from high temperature to low temperature.d. none of these54. Degree of freedom of the system ice-water-vapor will be-a. 1b. 3c. 0d. 255. Degree of freedom of the system liquid water with its vapor will be-a. 1b. 3c. 0d. 256. Degree of freedom of the system liquid solution of alcohol in water in equilibrium with its vapor-a. 1b. 3c. 0d. 257. For any system, what is the minimum number of degrees of freedom? a. 0b. 1c. 2d. 358. Given the table below for Freon 12 (entropy in BTU/ lb R; enthalpy in BTU/lb; specific volume in ft3/lb)-

What is its state at 40F and 25 psia?a. saturated liquidc. compressed liquidb. superheated vapord. saturated vapor59. Using the previous Freon 12 data table in problem #58, what is its entropy in BTU/lb R at 120F and 80% quality?a. 0.057b. 0.144c. 0.186d. 28.860. Using the previous Freon 12 data table, what is its latent heat (heat of vaporization) in BTU/1b at 80F?a. 0.219b. 0.423c. 26.4d. 58.961. Work or energy can be a function of all of the following except:a. force and distancec. power and timeb. torque and angular rotationd. force and time62. (U + PV) is a quantity called-a. flow energyb. shaft workc. entropyd. enthalpy63. ChE Board Exam Nov. 2009. A chemical engineer wants to extract energy from a geothermal power plant. At the top of the reservoir, the temperature of water is 30 C and as the water goes out of the coils, the temperature is 20C. If we analyze 2000 kg of water, how much maximum power can we extract from the reservoir? Let specific heat capacity of water be 4.186 kJ/kg C.a. 83,720 kJb. 2,763 kJc. 2,536,720 kJd. 80,957 kJ64. Consider a Carnot refrigerator and a Carnot heat pump operating between the same two thermal energy reservoirs. If the COP of the refrigerator is 3.4, the COP of the heat pump is-a. 1.7 b. 2.4 c. 3.4 d. 4.465. Steam is condensed at a constant temperature of 30C as it flows through the condenser of a power plant by rejecting heat at a rate of 55 MW. The rate of entropy change of steam as it flows through the condenser is-a. 1.83 MW/K b. 0.18 MW/K c. 0 MW/K d. 0.56 MW/K66. Steam is compressed from 5 MPa and 300C to 10 MPa isentropically. The final temperature of the steam is-a. 290C b. 300C c. 311C d. 401C67. Given that molar Cp of CO2 is 8.92 BTU/lbmol oR, and molar Cp of N2 is 6.95 BTU/lbmol oR, the calculated Cp per pound of mixture containing 25 vol% CO2 and 75 vol% N2 is:a. 0.23 BTU/lb Rb. 2.23 BTU/lb oRc. 5.21 BTU/lb Rd. 7.44 BTU/lb oR68. For an ideal liquid solution, which of the following is unity?a. Fugacity coefficientb. Activityc. Fugacityd. Activity coefficient69. In an ideal gas mixture, fugacity of a species is equal to its-a. partial pressure b. vapor pressure c. chemical potentiald. none of these70. An apple with an average mass of 0.15 kg and average specific heat of 3.65 kJ/kg-C is cooled from 20C to 5C. The entropy change of the apple is-a. 0.0288 kJ/K b. 0.192 kJ/K c. -0.526 kJ/Kd. 0 kJ/K71. MRII Question. The cooling energy ratio of a refrigeration cycle operating at -12C and 31C is-a. 4.39b. 3.58c. 6.07d. 5.1972. An inventor suggests that a house might be heated by using a refrigerator to draw energy as heat from the ground and reject energy as heat into the house. He claims that the energy supplied to the house as heat can exceed the work required to run the refrigerator. This:a. is impossible by first lawb. is impossible by second lawc. is impossible since heat energy flows from the (hot) house to the (cold) groundd. is possible73. In a thermally insulated kitchen, an ordinary refrigerator is turned on and its door is left open. The temperature of the room:a. remains constant according to the first law of thermodynamicsb. increases according to the first law of thermodynamicsc. decreases according to the first law of thermodynamicsd. remains constant according to the second law of thermodynamics74. An experimental electric jeepney running in Makati on 12V battery at 20m/s has a total energy storage of 2.0x107 Joules. If 8.0 KW is needed to move the vehicle, what is the quantity of energy supplied to the motor and how far will it travela. 500 A, 35km b. 814 A, 60km c. 960 A, 71kmd. 667 A, 50km75. An airjet operates at 2,500 rev/min and uses 7.89 x 103J of energy and exhausts 4.58 x 103 J for each crankshaft revolution. Determine the quantity of gasoline fuel consumed in one hour of operation if the heat of combustion is 4.03 x 107 J/liter.a. 24.2 L/hrb. 29.4 L/hrc. 13.4 L/hr d. 2.05 L/hr