Chapter 19. Heat Engines
|
|
- Meredith Conley
- 6 years ago
- Views:
Transcription
1 Chapter 19 Heat Engines
2 Thermo Processes Eint = Q+ W Adiabatic No heat exchanged Q = 0 and E int = W Isobaric Constant pressure W = P (V f V i ) and E int = Q + W Isochoric Constant Volume W = 0 and E int = Q Isothermal Constant temperature E int = 0 and Q = -W W V i = nrt ln V f
3
4 C P and C V Note that for all ideal gases: where R = 8.31 J/mol K is the universal gas constant. Slide 17-80
5 Heat Engines
6 Refrigerators
7 Important Concepts
8 2 nd Law: Perfect Heat Engine Can NOT exist! No energy is expelled to the cold reservoir It takes in some amount of energy and does an equal amount of work e = 100% It is an impossible engine No Free Lunch! Limit of efficiency is a Carnot Engine
9 Reversible and Irreversible Processes The reversible process is an idealization. All real processes on Earth are irreversible. Example of an approximate reversible process: The gas is compressed isothermally The gas is in contact with an energy reservoir Continually transfer just enough energy to keep the temperature constant The change in entropy is equal to zero for a reversible process and increases for irreversible processes. Section 22.3
10 The Maximum Efficiency Q T T = and ec = 1 Q T T c c c h h h COP C Q Tc W T T c = = h c COP H Q Th W T T h = = h c
11 Heat Engines In a steam turbine of a modern power plant, expanding steam does work by spinning the turbine. The steam is then condensed to liquid water and pumped back to the boiler to start the process again. First heat is transferred to the water in the boiler to create steam, and later heat is transferred out of the water to an external cold reservoir, in the condenser. This steam generator is an example of a heat engine Pearson Education, Inc. Slide 19-33
12 Heat Engine Eint = 0 for the entire cycle A heat engine is a device that takes in energy by heat and, operating in a cyclic process, expels a fraction of that energy by means of work A heat engine carries some working substance through a cyclical process The working substance absorbs energy by heat from a high temperature energy reservoir (Q h ) Work is done by the engine (W eng ) Energy is expelled as heat to a lower temperature reservoir (Q c )
13 Thermal Efficiency of a Heat Engine Eint = 0 for the entire cycle Weng = Qh Qc Thermal efficiency is defined as the ratio of the net work done by the engine during one cycle to the energy input at the higher temperature e W Q Q Q 1 Q Q Q eng h c c = = = h h h
14 Analyze this engine to determine (a) the net work done per cycle, (b) the engine s thermal efficiency and (c) the engine s power output if it runs at 600 rpm. Assume the gas is monatomic and follows the idealgas process above.
15 From Last Week.. A 4.00-L sample of a nitrogen gas confined to a cylinder, is carried through a closed cycle. The gas is initially at 1.00 atm and at 300 K. First, its pressure is tripled under constant volume. Then, it expands adiabatically to its original pressure. Finally, the gas is compressed isobarically to its original volume. (a) Draw a PV diagram of this cycle. (b) Find the number of moles of the gas. (c) Find the volumes and temperatures at the end of each process (d) Find the Work and heat for each process. (e) What was the net work done on the gas for this cycle?
16
17 The Brayton Cycle Many ideal-gas heat engines, such as jet engines in aircraft, use the Brayton Cycle, as shown. The cycle involves adiabatic compression (1-2), isobaric heating during combustion (2-3), adiabatic expansion which does work (3-4), and isobaric cooling (4-1). The efficiency is: 2013 Pearson Education, Inc. Slide 19-58
18 Otto Cycle The Otto cycle approximates the processes occurring in an internal combustion engine If the air-fuel mixture is assumed to be an ideal gas, then the efficiency of the Otto cycle is 1 e = 1 ( V ) 1 1 V γ 2 γ is the ratio of the molar specific heats V 1 / V 2 is called the compression ratio Typical values: Compression ratio of 8 γ = 1.4 e = 56% Efficiencies of real engines are 15% to 20% Mainly due to friction, energy transfer by conduction, incomplete combustion of the air-fuel mixture
19 No Perfect Heat Engines A perfect heat engine connected to a refrigerator would violate the second law of thermodynamics Pearson Education, Inc. Slide 19-46
20 Rank in order, from largest to smallest, the work W out performed by these four heat engines. e W Q Q Q 1 Q Q Q eng h c c = = = h h h A. W b > W a > W c > W d B. W b > W a > W b > W c C. W b > W a > W b = W c D. W d > W a = W b > W c E. W d > W a > W b > W c
21 Rank in order, from largest to smallest, the work W out performed by these four heat engines. e W Q Q Q 1 Q Q Q eng h c c = = = h h h A. W b > W a > W c > W d B. W b > W a > W b > W c C. W b > W a > W b = W c D. W d > W a = W b > W c E. W d > W a > W b > W c
22 QuickCheck 19.8 How much heat is exhausted to the cold reservoir? A J. B J. C J. D J. E. 0 J Pearson Education, Inc. Slide 19-54
23 QuickCheck 19.8 How much heat is exhausted to the cold reservoir? A J. B J. C J. D J. E. 0 J Pearson Education, Inc. Slide 19-55
24 QuickCheck 19.9 Which heat engine has the larger efficiency? A. Engine 1. B. Engine 2. C. They have the same efficiency. D. Can t tell without knowing the number of moles of gas Pearson Education, Inc. Slide 19-56
25 QuickCheck 19.9 Which heat engine has the larger efficiency? A. Engine 1. B. Engine 2. C. They have the same efficiency. D. Can t tell without knowing the number of moles of gas Pearson Education, Inc. Slide 19-57
26 Heat Pumps and Refrigerators Heat engines can run in reverse This is not a natural direction of energy transfer Must put some energy into a device to do this Devices that do this are called heat pumps or refrigerators COP = heating energy transferred at high temp work done by heat pump = Qh W COP = cooling energy transferred at low temp = work done by heat pump Q W C
27 Refrigerators In a sense, a refrigerator or air conditioner is the opposite of a heat engine. In a heat engine, heat energy flows from a hot reservoir to a cool reservoir, and work W out is produced. In a refrigerator, heat energy is somehow forced to flow from a cool reservoir to a hot reservoir, but it requires work W in to make this happen Pearson Education, Inc. Slide 19-41
28 Refrigerators Shown is the energytransfer diagram of a refrigerator. All state variables (pressure, temperature, thermal energy, etc.) return to their initial values once every cycle. The heat exhausted per cycle by a refrigerator is: Q H = Q C +W in 2013 Pearson Education, Inc. Slide 19-42
29 Refrigerators The purpose of a refrigerator is to remove heat from a cold reservoir, and it requires work input to do this. We define the coefficient of performance K of a refrigerator to be: If a perfect refrigerator could be built in which W in = 0, then heat would move spontaneously from cold to hot. This is expressly forbidden by the second law of thermodynamics: 2013 Pearson Education, Inc. Slide 19-43
30 QuickCheck 19.6 The coefficient of performance of this refrigerator is A B C D E Pearson Education, Inc. Slide 19-44
31 QuickCheck 19.6 The coefficient of performance of this refrigerator is A B C D E Pearson Education, Inc. Slide 19-45
32 Refrigerators Understanding a refrigerator is a little harder than understanding a heat engine. Heat is always transferred from a hotter object to a colder object. The gas in a refrigerator can extract heat Q C from the cold reservoir only if the gas temperature is lower than the cold-reservoir temperature T C. Heat energy is then transferred from the cold reservoir into the colder gas. The gas in a refrigerator can exhaust heat Q H to the hot reservoir only if the gas temperature is higher than the hot-reservoir temperature T H. Heat energy is then transferred from the warmer gas into the hot reservoir.
33 Refrigerators
34
35 Heat Pumps
36 Coefficient of Performance The effectiveness of a heat pump is described by a number called the coefficient of performance (COP) In heating mode, the COP is the ratio of the heat transferred in to the work required COP = energy transferred at high temp work done by heat pump = Q h W
37 A heat pump, is essentially an air conditioner installed backward. It extracts energy from colder air outside and deposits it in a warmer room. Suppose that the ratio of the actual energy entering the room to the work done by the device s motor is 10.0% of the theoretical maximum ratio. Determine the energy entering the room per joule of work done by the motor, given that the inside temperature is 20.0 C and the outside temperature is 5.00 C. energy transferred at high temp Qh COP heating = = work done by heat pump W Q W h Qh = W Carnot cycle Qh Th 293 K = = = 1.17 W T T 293 K 268 K h c 1.17 joules of energy enter the room by heat for each joule of work done.
38 Second Law Clausius Form It is impossible to construct a cyclical machine whose sole effect is to transfer energy continuously by heat from one object to another object at a higher temperature without the input of energy by work. Or energy does not transfer spontaneously by heat from a cold object to a hot object. Section 22.2
39 The Limits of Efficiency A perfectly reversible engine must use only two types of processes: 1. Frictionless mechanical interactions with no heat transfer (Q = 0) 2. Thermal interactions in which heat is transferred in an isothermal process (ΔE th = 0). Any engine that uses only these two types of processes is called a Carnot engine. A Carnot engine is a perfectly reversible engine; it has the maximum possible thermal efficiency and, if operated as a refrigerator, the maximum possible coefficient of performance.
40 2 nd Law: Carnot s Theorem No real heat engine operating between two energy reservoirs can be more efficient than a Carnot engine operating between the same two reservoirs All real engines are less efficient than a Carnot engine because they do not operate through a reversible cycle The efficiency of a real engine is further reduced by friction, energy losses through conduction, etc French engineer
41 The Carnot cycle is an ideal-gas cycle that consists of the two adiabatic processes (Q = 0) and the two isothermal processes (ΔE th = 0) shown. These are the two types of processes allowed in a perfectly reversible gas engine. Section 22.4
42 Carnot Cycle, A to B A B is an isothermal expansion. The gas is placed in contact with the high temperature reservoir, T h. The gas absorbs heat Q h. The gas does work W AB in raising the piston. Section 22.4
43 Carnot Cycle, B to C B C is an adiabatic expansion. The base of the cylinder is replaced by a thermally nonconducting wall. No energy enters or leaves the system by heat. The temperature falls from T h to T c. The gas does work W BC. Section 22.4
44 Carnot Cycle, C to D The gas is placed in thermal contact with the cold temperature reservoir. C D is an isothermal compression. The gas expels energy Q c. Work W CD is done on the gas. Section 22.4
45 Carnot Cycle, D to A D A is an adiabatic compression. The base is replaced by a thermally nonconducting wall. So no heat is exchanged with the surroundings. The temperature of the gas increases from T c to T h. The work done on the gas is W DA. Section 22.4
46 Carnot Engine Carnot Cycle A heat engine operating in an ideal, reversible cycle (now called a Carnot cycle) between two reservoirs is the most efficient engine possible. This sets an upper limit on the efficiencies of all other engines Q T T = and ec = 1 Q T T c c c h h h Temperatures must be in Kelvins
47 (a) (b) Carnot Cycle Problem An ideal gas is taken through a Carnot cycle. The isothermal expansion occurs at 250 C, and the isothermal compression takes place at 50.0 C. The gas takes in J of energy from the hot reservoir during the isothermal expansion. Find the energy expelled to the cold reservoir in each cycle and (b) the net work done by the gas in each cycle.
48 Carnot Cycle in Reverse Theoretically, a Carnot-cycle heat engine can run in reverse This would constitute the most effective heat pump available This would determine the maximum possible COPs for a given combination of hot and cold reservoirs
49 COP, Heating Mode COP is similar to efficiency Q h is typically higher than W Values of COP are generally greater than 1 It is possible for them to be less than 1 We would like the COP to be as high as possible
50 COP, Cooling Mode In cooling mode, you gain energy from a cold temperature reservoir COP = Q c W A good refrigerator should have a high COP Typical values are 5 or 6
51
52 Can this refrigerator be built? W = Q Q H COP = Q c W C COP C Q Tc W T T c = = h c
53 2nd Law of Thermo Heat flows spontaneously from a substance at a higher temperature to a substance at a lower temperature and does not flow spontaneously in the reverse direction. Heat flows from hot to cold. Alternative: Irreversible processes must have an increase in Entropy; Reversible processes have no change in Entropy. Entropy is a measure of disorder in a system
54 The Limits of Efficiency Everyone knows that heat can produce motion. That it possesses vast motive power no one can doubt, in these days when the steam engine is everywhere so well known.... Notwithstanding the satisfactory condition to which they have been brought today, their theory is very little understood. The question has often been raised whether the motive power of heat is unbounded, or whether the possible improvements in steam engines have an assignable limit. Sadi Carnot
55 Reversible and Irreversible Processes The Arrow of Time! Play the Movie Backwards!
56 Entropy
57 Entropy on a Microscopic Scale We can treat entropy from a microscopic viewpoint through statistical analysis of molecular motions. A connection between entropy and the number of microstates (W) for a given macrostate is S = k B ln W The more microstates that correspond to a given macrostate, the greater the entropy of that macrostate. This shows that entropy is a measure of disorder. Section 22.8
58
59 Free Expansion Consider an adiabatic free expansion. This process is irreversible since the gas would not spontaneously crowd into half the volume after filling the entire volume. The change in entropy is greater than zero for a irreversible processes. Section 22.7
60 S in a Free Expansion Consider an adiabatic free expansion. This process is irreversible since the gas would not spontaneously crowd into half the volume after filling the entire volume. Q = 0 but we need to find Q r Choose an isothermal, reversible expansion in which the gas pushes slowly against the piston while energy enters from a reservoir to keep T constant. dq T f r S = = i S = nr 1 T V ln f Vi i f dq r Since V f > V i, S is positive This indicates that both the entropy and the disorder of the gas increase as a result of the irreversible adiabatic expansion. Section 22.7
61 Entropy and Heat The original formulation of entropy dealt with the transfer of energy by heat in a reversible process. Let dq r be the amount of energy transferred by heat when a system follows a reversible path. The change in entropy, ds is ds = dq r T The change in entropy depends only on the endpoints and is independent of the actual path followed. The entropy change for an irreversible process can be determined by calculating the change in entropy for a reversible process that connects the same initial and final points. Section 22.6
62 dq T f r S = = i 1 T i f dq r Entropy increases when: Temperature increases Q flows into the system Volume increases Pressure decreases??
63 Heat Death of the Universe Ultimately, the entropy of the Universe should reach a maximum value. At this value, the Universe will be in a state of uniform temperature and density. All physical, chemical, and biological processes will cease. The state of perfect disorder implies that no energy is available for doing work. This state is called the heat death of the Universe.
64
65 Big Bang Cosmogenesis
66 The Stellar Age Stars Rule for a Trillion Years
67 In about 5 billion years, Our Sun will swell into a cool Red Giant, engulfing Mercury, Venus and possibly Earth!
68 The Degenerate Age After about 100 trillion, years, the stars are dead. By years, the material in the "Local Galaxy" consists of isolated stellar remnants and black holes. Everything is cold and dark.
69 The Black Hole Age All the stars turn into black holes. After about years, all the black holes are gone.
70 The Dark Era The remaining black holes evaporate: first the small ones, and then the supermassive black holes. All matter that used to make up the stars and galaxies has now degenerated into photons and leptons.
71
72
73
74
75
76
77
78 Boltzmann was subject to rapid alternation of depressed moods with elevated, expansive or irritable moods, likely the symptoms of undiagnosed bipolar disorder. On September 5, 1906, while on a summer vacation in Duino, near Trieste, Boltzmann hanged himself during an attack of depression. He is buried in the Viennese Zentralfriedhof; his tombstone bears the inscription.
Chapter 19. Heat Engines
Chapter 19 Heat Engines QuickCheck 19.11 The efficiency of this Carnot heat engine is A. Less than 0.5. B. 0.5. C. Between 0.5 and 1.0. D. 2.0. E. Can t say without knowing Q H. 2013 Pearson Education,
More informationChapter 20. Heat Engines, Entropy and the Second Law of Thermodynamics. Dr. Armen Kocharian
Chapter 20 Heat Engines, Entropy and the Second Law of Thermodynamics Dr. Armen Kocharian First Law of Thermodynamics Review Review: The first law states that a change in internal energy in a system can
More informationSpeed Distribution at CONSTANT Temperature is given by the Maxwell Boltzmann Speed Distribution
Temperature ~ Average KE of each particle Particles have different speeds Gas Particles are in constant RANDOM motion Average KE of each particle is: 3/2 kt Pressure is due to momentum transfer Speed Distribution
More informationChapter 12. The Laws of Thermodynamics
Chapter 12 The Laws of Thermodynamics First Law of Thermodynamics The First Law of Thermodynamics tells us that the internal energy of a system can be increased by Adding energy to the system Doing work
More informationChapter 12. The Laws of Thermodynamics. First Law of Thermodynamics
Chapter 12 The Laws of Thermodynamics First Law of Thermodynamics The First Law of Thermodynamics tells us that the internal energy of a system can be increased by Adding energy to the system Doing work
More informationHandout 12: Thermodynamics. Zeroth law of thermodynamics
1 Handout 12: Thermodynamics Zeroth law of thermodynamics When two objects with different temperature are brought into contact, heat flows from the hotter body to a cooler one Heat flows until the temperatures
More informationLecture Outline Chapter 18. Physics, 4 th Edition James S. Walker. Copyright 2010 Pearson Education, Inc.
Lecture Outline Chapter 18 Physics, 4 th Edition James S. Walker Chapter 18 The Laws of Thermodynamics Units of Chapter 18 The Zeroth Law of Thermodynamics The First Law of Thermodynamics Thermal Processes
More informationHandout 12: Thermodynamics. Zeroth law of thermodynamics
1 Handout 12: Thermodynamics Zeroth law of thermodynamics When two objects with different temperature are brought into contact, heat flows from the hotter body to a cooler one Heat flows until the temperatures
More informationTemperature Thermal Expansion Ideal Gas Law Kinetic Theory Heat Heat Transfer Phase Changes Specific Heat Calorimetry Heat Engines
Temperature Thermal Expansion Ideal Gas Law Kinetic Theory Heat Heat Transfer Phase Changes Specific Heat Calorimetry Heat Engines Zeroeth Law Two systems individually in thermal equilibrium with a third
More informationChapter 16 Thermodynamics
Nicholas J. Giordano www.cengage.com/physics/giordano Chapter 16 Thermodynamics Thermodynamics Introduction Another area of physics is thermodynamics Continues with the principle of conservation of energy
More informationThe first law of thermodynamics. U = internal energy. Q = amount of heat energy transfer
Thermodynamics Investigation of the energy transfer by heat and work and how natural systems behave (Q) Heat transfer of energy due to temp differences. (W) Work transfer of energy through mechanical means.
More informationClass 22 - Second Law of Thermodynamics and Entropy
Class 22 - Second Law of Thermodynamics and Entropy The second law of thermodynamics The first law relates heat energy, work and the internal thermal energy of a system, and is essentially a statement
More informationHeat Machines (Chapters 18.6, 19)
eat Machines (hapters 8.6, 9) eat machines eat engines eat pumps The Second Law of thermodynamics Entropy Ideal heat engines arnot cycle Other cycles: Brayton, Otto, Diesel eat Machines Description The
More informationChapter 12 Thermodynamics
Chapter 12 Thermodynamics 12.1 Thermodynamic Systems, States, and Processes System: definite quantity of matter with real or imaginary boundaries If heat transfer is impossible, the system is thermally
More informationLecture 26. Second law of thermodynamics. Heat engines and refrigerators.
ecture 26 Second law of thermodynamics. Heat engines and refrigerators. The Second aw of Thermodynamics Introduction The absence of the process illustrated above indicates that conservation of energy is
More informationThe First Law of Thermodynamics
Thermodynamics The First Law of Thermodynamics Thermodynamic Processes (isobaric, isochoric, isothermal, adiabatic) Reversible and Irreversible Processes Heat Engines Refrigerators and Heat Pumps The Carnot
More informationHeat What is heat? Work = 2. PdV 1
eat What is heat? eat (Q) is the flow or transfer of energy from one system to another Often referred to as heat flow or heat transfer Requires that one system must be at a higher temperature than the
More informationTHERMODYNAMICS. Zeroth law of thermodynamics. Isotherm
12 THERMODYNAMICS Zeroth law of thermodynamics Two systems separately in thermal equilibrium with a third system are in thermal equilibrium with each other. Isotherm It is the graph connecting pressure
More informationThermodynamic Systems, States, and Processes
Thermodynamics Thermodynamic Systems, States, and Processes A thermodynamic system is described by an equation of state, such as the ideal gas law. The location of the state can be plotted on a p V diagram,
More informationAP PHYSICS 2 WHS-CH-15 Thermodynamics Show all your work, equations used, and box in your answers!
AP PHYSICS 2 WHS-CH-15 Thermodynamics Show all your work, equations used, and box in your answers! Nicolas Léonard Sadi Carnot (1796-1832) Sadi Carnot was a French military engineer and physicist, often
More informationChapter 4 - Second Law of Thermodynamics
Chapter 4 - The motive power of heat is independent of the agents employed to realize it. -Nicolas Léonard Sadi Carnot David J. Starling Penn State Hazleton Fall 2013 An irreversible process is a process
More informationSurvey of Thermodynamic Processes and First and Second Laws
Survey of Thermodynamic Processes and First and Second Laws Please select only one of the five choices, (a)-(e) for each of the 33 questions. All temperatures T are absolute temperatures. All experiments
More informationReversible Processes. Furthermore, there must be no friction (i.e. mechanical energy loss) or turbulence i.e. it must be infinitely slow.
Reversible Processes A reversible thermodynamic process is one in which the universe (i.e. the system and its surroundings) can be returned to their initial conditions. Because heat only flows spontaneously
More informationPhysics 150. Thermodynamics. Chapter 15
Physics 150 Thermodynamics Chapter 15 The First Law of Thermodynamics Let s consider an ideal gas confined in a chamber with a moveable piston If we press the piston è the gas in the chamber compresses
More informationThermodynamics: The Laws
Thermodynamics: The Laws Resources: Serway The Laws of Thermodynamics: 12 AP Physics B Videos Physics B Lesson 29: Laws of Thermodynamics Thermodynamics Thermodynamics is the study of heat and thermal
More informationChapter 20 Entropy and the 2nd Law of Thermodynamics
Chapter 20 Entropy and the 2nd Law of Thermodynamics A one-way processes are processes that can occur only in a certain sequence and never in the reverse sequence, like time. these one-way processes are
More informationS = S(f) S(i) dq rev /T. ds = dq rev /T
In 1855, Clausius proved the following (it is actually a corollary to Clausius Theorem ): If a system changes between two equilibrium states, i and f, the integral dq rev /T is the same for any reversible
More informationTHERMODYNAMICS b) If the temperatures of two bodies are equal then they are said to be in thermal equilibrium.
THERMODYNAMICS Important Points:. Zeroth Law of Thermodynamics: a) This law gives the concept of temperature. b) If the temperatures of two bodies are equal then they are said to be in thermal equilibrium.
More informationCHAPTER 15 The Laws of Thermodynamics. Units
CHAPTER 15 The Laws of Thermodynamics Units The First Law of Thermodynamics Thermodynamic Processes and the First Law Human Metabolism and the First Law The Second Law of Thermodynamics Introduction Heat
More informationChapter 11 Heat Engines and The Second Law of Thermodynamics
Chapter 11 Heat Engines and The Second Law of Thermodynamics Heat Engines Heat engines use a temperature difference involving a high temperature (T H ) and a low temperature (T C ) to do mechanical work.
More informationChapter 20 The Second Law of Thermodynamics
Chapter 20 The Second Law of Thermodynamics When we previously studied the first law of thermodynamics, we observed how conservation of energy provided us with a relationship between U, Q, and W, namely
More informationLecture 2 Entropy and Second Law
Lecture 2 Entropy and Second Law Etymology: Entropy, entropie in German. En from energy and trope turning toward Turning to energy Motivation for a Second Law!! First law allows us to calculate the energy
More informationEntropy & the Second Law of Thermodynamics
PHYS102 Previous Exam Problems CHAPTER 20 Entropy & the Second Law of Thermodynamics Entropy gases Entropy solids & liquids Heat engines Refrigerators Second law of thermodynamics 1. The efficiency of
More informationThermodynamics Second Law Heat Engines
Thermodynamics Second Law Heat Engines Lana Sheridan De Anza College May 10, 2018 Last time entropy (microscopic perspective) Overview heat engines heat pumps Carnot engines Heat Engines Steam engines
More informationLecture 10: Heat Engines and Reversible Processes
Lecture 10: Heat Engines and Reversible Processes Last time we started discussing cyclic heat engines these are devices that convert heat energy into mechanical work We found that in general, heat engines
More informationPhysics 231. Topic 14: Laws of Thermodynamics. Alex Brown Dec MSU Physics 231 Fall
Physics 231 Topic 14: Laws of Thermodynamics Alex Brown Dec 7-11 2015 MSU Physics 231 Fall 2015 1 8 th 10 pm correction for 3 rd exam 9 th 10 pm attitude survey (1% for participation) 10 th 10 pm concept
More informationCHAPTER - 12 THERMODYNAMICS
CHAPER - HERMODYNAMICS ONE MARK QUESIONS. What is hermodynamics?. Mention the Macroscopic variables to specify the thermodynamics. 3. How does thermodynamics differ from Mechanics? 4. What is thermodynamic
More informationΔU = Q W. Tue Dec 1. Assign 13/14 Friday Final: Fri Dec 11 2:30PM WALTER 145. Thermodynamics 1st Law. 2 nd Law. Heat Engines and Refrigerators
Tue Dec 1 Thermodynamics 1st Law ΔU = Q W 2 nd Law SYS Heat Engines and Refrigerators Isobaric: W = PΔV Isochoric: W = 0 Isothermal: ΔU = 0 Adiabatic: Q = 0 Assign 13/14 Friday Final: Fri Dec 11 2:30PM
More informationChapter 16 The Second Law of Thermodynamics
Chapter 16 The Second Law of Thermodynamics To examine the directions of thermodynamic processes. To study heat engines. To understand internal combustion engines and refrigerators. To learn and apply
More informationDistinguish between an isothermal process and an adiabatic process as applied to an ideal gas (2)
1. This question is about thermodynamic processes. (a) Distinguish between an isothermal process and an adiabatic process as applied to an ideal gas.......... An ideal gas is held in a container by a moveable
More informationPhysics 202 Homework 5
Physics 202 Homework 5 Apr 29, 2013 1. A nuclear-fueled electric power plant utilizes a so-called boiling water reac- 5.8 C tor. In this type of reactor, nuclear energy causes water under pressure to boil
More informationThe area under the graph in a PV diagram is equal in magnitude to
a volume V and exerts a uniform pressure P on the cylinder walls and the piston. The gas is compressed slowly enough so the system remains essentially in thermodynamic equilibrium at all times. As the
More informationVersion 001 HW 15 Thermodynamics C&J sizemore (21301jtsizemore) 1
Version 001 HW 15 Thermodynamics C&J sizemore 21301jtsizemore 1 This print-out should have 38 questions. Multiple-choice questions may continue on the next column or page find all choices before answering.
More informationIrreversible Processes
Lecture 15 Heat Engines Review & Examples p p b b Hot reservoir at T h p a a c adiabats Heat leak Heat pump Q h Q c W d V 1 V 2 V Cold reservoir at T c Lecture 15, p 1 Irreversible Processes Entropy-increasing
More information10. Heat devices: heat engines and refrigerators (Hiroshi Matsuoka)
10 Heat devices: heat engines and refrigerators (Hiroshi Matsuoka) 1 In this chapter we will discuss how heat devices work Heat devices convert heat into work or work into heat and include heat engines
More informationThe laws of Thermodynamics. Work in thermodynamic processes
The laws of Thermodynamics ork in thermodynamic processes The work done on a gas in a cylinder is directly proportional to the force and the displacement. = F y = PA y It can be also expressed in terms
More informationEngineering Thermodynamics. Chapter 5. The Second Law of Thermodynamics
5.1 Introduction Chapter 5 The Second aw of Thermodynamics The second law of thermodynamics states that processes occur in a certain direction, not in just any direction. Physical processes in nature can
More informationLaws of Thermodynamics
Laws of Thermodynamics The Three Laws of Thermodynamics - The first lawof thermodynamics, also called conservation of energy. We can use this knowledge to determine the amount of energy in a system, the
More informationExamples. Fire Piston (demo) Example (Comparison of processes)
Examples Fire Piston (demo) Fire Piston istory http://en.wikipedia.org/wiki/fire_piston Example 19.68 (Comparison of processes) Fire piston calculations http://complex.gmu.edu/www-phys/phys262/soln/fire_piston.pdf
More informationThe Limits of Efficiency. The Limits of Efficiency. The Limits of Efficiency
The Limits of Efficiency If a perfectly reversible heat engine is used to operate a perfectly reversible refrigerator, the two devices exactly cancel each other. 2017 Pearson Education, Inc. Slide 20-1
More informationPhysics 121, April 29, The Second Law of Thermodynamics.
Physics 121, April 29, 2008. The Second Law of Thermodynamics. http://www.horizons.uc.edu/masterjuly1998/oncampus.htm Physics 121. April 29, 2008. Course Information Topics to be discussed today: The Second
More information18.13 Review & Summary
5/2/10 10:04 PM Print this page 18.13 Review & Summary Temperature; Thermometers Temperature is an SI base quantity related to our sense of hot and cold. It is measured with a thermometer, which contains
More informationPhysics 115. Specific heats revisited Entropy. General Physics II. Session 13
Physics 115 General Physics II Session 13 Specific heats revisited Entropy R. J. Wilkes Email: phy115a@u.washington.edu Home page: http://courses.washington.edu/phy115a/ 4/22/14 Physics 115 1 Lecture Schedule
More informationChapter 20 Second Law of Thermodynamics. Copyright 2009 Pearson Education, Inc.
Chapter 20 Second Law of Thermodynamics It is easy to produce thermal energy using work, but how does one produce work using thermal energy? This is a heat engine; mechanical energy can be obtained from
More information(prev) (top) (next) (Throughout, we will assume the processes involve an ideal gas with constant n.)
1 of 9 8/22/12 9:51 PM (prev) (top) (next) Thermodynamics 1 Thermodynamic processes can be: 2 isothermal processes, ΔT = 0 (so P ~ 1 / V); isobaric processes, ΔP = 0 (so T ~ V); isovolumetric or isochoric
More informationOctober 18, 2011 Carnot cycle - 1
Carnot Cycle In 1824, Sadi Carnot (1796-1832) published a short book, eflections on the Motive Power of Fire (The book is now free online You should try it out) To construct an engine, Carnot noted, at
More informationPhysics 1501 Lecture 37
Physics 1501: Lecture 37 Todays Agenda Announcements Homework #12 (Dec. 9): 2 lowest dropped Midterm 2 in class Wednesday Friday: review session bring your questions Todays topics Chap.18: Heat and Work»
More informationIrreversible Processes
Lecture 15 Heat Engines Review & Examples p p b b Hot reservoir at T h p a a c adiabats Heat leak Heat pump Q h Q c W d V 1 V 2 V Cold reservoir at T c Lecture 15, p 1 Irreversible Processes Entropy-increasing
More informationSecond Law of Thermodynamics
Dr. Alain Brizard College Physics II (PY 211) Second Law of Thermodynamics Textbook Reference: Chapter 20 sections 1-4. Second Law of Thermodynamics (Clausius) Heat flows naturally from a hot object to
More informationPhysical Biochemistry. Kwan Hee Lee, Ph.D. Handong Global University
Physical Biochemistry Kwan Hee Lee, Ph.D. Handong Global University Week 3 CHAPTER 2 The Second Law: Entropy of the Universe increases What is entropy Definition: measure of disorder The greater the disorder,
More information11/29/2017 IRREVERSIBLE PROCESSES. UNIT 2 Thermodynamics: Laws of thermodynamics, ideal gases, and kinetic theory
11/9/017 AP PHYSICS UNIT Thermodynamics: Laws of thermodynamics, ideal gases, and kinetic theory CHAPTER 13 SECOND LAW OF THERMODYNAMICS IRREVERSIBLE PROCESSES The U G of the water-earth system at the
More informationThe need for something else: Entropy
Lecture 27 Goals: Ch. 18 ualitatively understand 2 nd Law of Thermodynamics Ch. 19 Understand the relationship between work and heat in a cycling process Follow the physics of basic heat engines and refrigerators.
More informationIrreversible Processes
Irreversible Processes Examples: Block sliding on table comes to rest due to friction: KE converted to heat. Heat flows from hot object to cold object. Air flows into an evacuated chamber. Reverse process
More information1. INTRODUCTION TO REFRIGERATION AND AIR CONDITION
CHAPTER ONE 1. INTRODUCTION TO REFRIGERATION AND AIR CONDITION Refrigeration may be defined as the process of reducing and maintaining a temperature of a space or material below that of the surroundings.
More informationR13 SET - 1 '' ''' '' ' '''' Code No RT21033
SET - 1 II B. Tech I Semester Supplementary Examinations, June - 2015 THERMODYNAMICS (Com. to ME, AE, AME) Time: 3 hours Max. Marks: 70 Note: 1. Question Paper consists of two parts (Part-A and Part-B)
More information12 The Laws of Thermodynamics
June 14, 1998 12 The Laws of Thermodynamics Using Thermal Energy to do Work Understanding the laws of thermodynamics allows us to use thermal energy in a practical way. The first law of thermodynamics
More informationDownloaded from
Chapter 12 (Thermodynamics) Multiple Choice Questions Single Correct Answer Type Q1. An ideal gas undergoes four different processes from the same initial state (figure). Four processes are adiabatic,
More informationFree expansion (Joule); Constant U Forced expansion (Joule-Kelvin); Constant H. Joule-Kelvin coefficient - heating or cooling on JK expansion?
...Thermodynamics Adiabats: How c P and c V get into the exponent PV γ Free expansion (Joule); Constant U Forced expansion (Joule-Kelvin); Constant H Joule-Kelvin coefficient - heating or cooling on JK
More informationThermodynamics. AP Physics B
Thermodynamics AP Physics B ork done by a gas Suppose you had a piston filled with a specific amount of gas. As you add heat, the temperature rises and thus the volume of the gas expands. The gas then
More informationThermodynamics. AP Physics B
Thermodynamics AP Physics B Important Distinctions Thermodynamics study of processes in which energy is transferred as heat and work. There is a difference between heat and work: Heat is energy transferred
More informationUniversity of Washington Department of Chemistry Chemistry 452 Summer Quarter 2014
Lecture 0 7/6/ ERD: 5. DeVoe:.3.,.3.3 University of Washington Department of Chemistry Chemistry 5 Summer Quarter 0 A. Work and the Second Law of Thermodynamics: Efficiency of eat Engines One of the most
More informationGechstudentszone.wordpress.com. Chapter 6. Vittal.K
Chapter 6 Vittal.K Leads Up To Second Law Of Thermodynamics Heat source T 1 Q +ve w possible. It is now clear that we can t construct a heat engine with just one +ve heat interaction. The above engine
More informationThermodynamic system is classified into the following three systems. (ii) Closed System It exchanges only energy (not matter) with surroundings.
1 P a g e The branch of physics which deals with the study of transformation of heat energy into other forms of energy and vice-versa. A thermodynamical system is said to be in thermal equilibrium when
More informationChapter 1: FUNDAMENTAL CONCEPTS OF THERMODYNAMICS AND VARIOUS THERMODYMIC PROCESSES
Chapter 1: FUNDAMENTAL CONCEPTS OF THERMODYNAMICS AND VARIOUS THERMODYMIC PROCESSES Thermodynamics is that branch of science which deals with energy transfer A system may be closed, open or isolated system
More informationT s change via collisions at boundary (not mechanical interaction)
Lecture 14 Interaction of 2 systems at different temperatures Irreversible processes: 2nd Law of Thermodynamics Chapter 19: Heat Engines and Refrigerators Thermal interactions T s change via collisions
More informationUniversity Physics (Prof. David Flory) Chapt_21 Monday, November 26, 2007 Page 1
University Physics (Prof. David Flory) Chapt_21 Monday, November 26, 2007 Page 1 Name: Date: 1. Let k be the Boltzmann constant. If the configuration of the molecules in a gas changes so that the multiplicity
More informationPhysics 207 Lecture 27. Lecture 26. Chapters 18, entropy and second law of thermodynamics Chapter 19, heat engines and refrigerators
Goals: Lecture 26 Chapters 18, entropy and second law of thermodynamics Chapter 19, heat engines and refrigerators Reading assignment for Wednesday: Chapter 20. Physics 207: Lecture 27, Pg 1 Entropy A
More informationEntropy and the Second and Third Laws of Thermodynamics
CHAPTER 5 Entropy and the Second and Third Laws of Thermodynamics Key Points Entropy, S, is a state function that predicts the direction of natural, or spontaneous, change. Entropy increases for a spontaneous
More informationLecture 9. Heat engines. Pre-reading: 20.2
Lecture 9 Heat engines Pre-reading: 20.2 Review Second law when all systems taking part in a process are included, the entropy remains constant or increases. No process is possible in which the total entropy
More informationSecond Law of Thermodynamics -
Second Law of Thermodynamics - REVIEW ENTROPY EXAMPLE Dr. Garrick 1/19/09 First Law of Thermodynamics you can t win! First Law of Thermodynamics: Energy cannot be Created or Destroyed the total energy
More informationLecture 44: Review Thermodynamics I
ME 00 Thermodynamics I Lecture 44: Review Thermodynamics I Yong Li Shanghai Jiao Tong University Institute of Refrigeration and Cryogenics 800 Dong Chuan Road Shanghai, 0040, P. R. China Email : liyo@sjtu.edu.cn
More informationTHERMODYNAMICS CONCEPTUAL PROBLEMS
THERMODYNAMICS CONCEPTUAL PROBLEMS Q-01 Is the heat supplied to a system always equal to the increases in its internal energy? Ans Acc. to first law of thermo- dynamics If heat is supplied in such a manner
More informationTwo mark questions and answers UNIT II SECOND LAW 1. Define Clausius statement. It is impossible for a self-acting machine working in a cyclic process, to transfer heat from a body at lower temperature
More informationHow to please the rulers of NPL-213 the geese
http://www.walkingmountains. org/2015/03/reintroduction-ofthe-canada-goose/ How to please the rulers of NPL-213 the geese (Entropy and the 2 nd Law of Thermodynamics) Physics 116 2017 Tues. 3/21, Thurs
More informationPHY101: Major Concepts in Physics I
Welcome back to PHY101: Major Concepts in Physics I Photo: S. T. Cummins Photo: S. T. Cummins Announcements Today is our final class! We will first discuss more on Chapters 14-15 and then conduct a short
More informationClassification following properties of the system in Intensive and Extensive
Unit I Classification following properties of the system in Intensive and Extensive Extensive : mass, weight, volume, potential energy, Kinetic energy, Internal energy, entropy, exergy, energy, magnetization
More informationHeat Engines and Refrigerators
Lecture 26, Dec. 1 Goals: Chapter 19 Understand the relationship between work and heat in a cycling process Follow the physics of basic heat engines and refrigerators. Recognize some practical applications
More informationI.D The Second Law Q C
I.D he Second Law he historical development of thermodynamics follows the industrial revolution in the 19 th century, and the advent of heat engines. It is interesting to see how such practical considerations
More informationCyclic Processes. water
Name Cyclic Processes Cyclic Processes A fixed quantity of ideal gas is contained within a metal cylinder that is sealed with a movable, frictionless, insulating piston. (The piston can move up or down
More informationMinimum Bias Events at ATLAS
Camille Bélanger-Champagne McGill University Lehman College City University of New York Thermodynamics Charged Particle and Statistical Correlations Mechanics in Minimum Bias Events at ATLAS Thermodynamics
More information1. Second Law of Thermodynamics
1. Second Law of hermodynamics he first law describes how the state of a system changes in response to work it performs and heat absorbed. he second law deals with direction of thermodynamic processes
More information0 questions at random and keep in order
Page 1 of 9 This chapter has 57 questions. Scroll down to see and select individual questions or narrow the list using the checkboxes below. 0 questions at random and keep in order s - (45) - (13) Fill
More information8.21 The Physics of Energy Fall 2009
MIT OpenCourseWare http://ocw.mit.edu 8.21 The Physics of Energy Fall 2009 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. 8.21 Lecture 10 Phase Change
More informationA thermodynamic system is taken from an initial state X along the path XYZX as shown in the PV-diagram.
AP Physics Multiple Choice Practice Thermodynamics 1. The maximum efficiency of a heat engine that operates between temperatures of 1500 K in the firing chamber and 600 K in the exhaust chamber is most
More informationLecture 2 Entropy and Second Law
Lecture 2 Entropy and Second Law Etymology: Entropy, entropie in German. En from energy and trope turning toward Turning to energy Zeroth law temperature First law energy Second law - entropy CY1001 2010
More informationCARNOT CYCLE = T = S ( U,V )
hermodynamics CANO CYCE Do not trouble students with history In 1824, Sadi Carnot (1796-1832) published a short book, eflections on the Motive Power of Fire (he book is now free online You should try it
More informationBasic Thermodynamics. Prof. S. K. Som. Department of Mechanical Engineering. Indian Institute of Technology, Kharagpur.
Basic Thermodynamics Prof. S. K. Som Department of Mechanical Engineering Indian Institute of Technology, Kharagpur Lecture - 06 Second Law and its Corollaries I Good afternoon, I welcome you all to this
More informationPhysics 101: Lecture 28 Thermodynamics II
Physics 101: Lecture 28 Thermodynamics II Final Today s lecture will cover Textbook Chapter 15.6-15.9 Check Final Exam Room Assignment! Bring ID! Be sure to check your gradebook! Physics 101: Lecture 28,
More informationTHE SECOND LAW OF THERMODYNAMICS. Professor Benjamin G. Levine CEM 182H Lecture 5
THE SECOND LAW OF THERMODYNAMICS Professor Benjamin G. Levine CEM 182H Lecture 5 Chemical Equilibrium N 2 + 3 H 2 2 NH 3 Chemical reactions go in both directions Systems started from any initial state
More information6. (6) Show all the steps of how to convert 50.0 F into its equivalent on the Kelvin scale.
General Physics I Quiz 8 - Ch. 13 - Temperature & Kinetic Theory July 30, 2009 Name: Make your work clear to the grader. Show formulas used. Give correct units and significant figures. Partial credit is
More information