Chapter 1515.1 Thermodynamic Systems and Their Surroundings15.2 The Zeroth Law of ThermodynamicsSlide 415.3 The First Law of ThermodynamicsSlide 6Slide 7Slide 8Slide 9Slide 10Slide 1115.4 Thermal ProcessesSlide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 1915.5 Thermal Processes Using and Ideal GasSlide 21Slide 22Slide 2315.6 Specific Heat CapacitiesSlide 25Slide 2615.7 The Second Law of Thermodynamics15.8 Heat EnginesSlide 29Slide 30Slide 3115.9 Carnot’s Principle and the Carnot EngineSlide 33Slide 34Slide 35Slide 3615.10 Refrigerators, Air Conditioners, and Heat PumpsSlide 38Slide 39Slide 40Slide 41Slide 42Slide 4315.11 EntropySlide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 5215.12 The Third Law of ThermodynamicsChapter 15Thermodynamics15.1 Thermodynamic Systems and Their SurroundingsThermodynamics is the branch of physics that is built upon the fundamental laws that heat and work obey.The collection of objects on which attention is being focused is called the system, while everything elsein the environment is called the surroundings.Walls that permit heat flow are called diathermal walls,while walls that do not permit heat flow are calledadiabatic walls.To understand thermodynamics, it is necessary to describe the state of a system.15.2 The Zeroth Law of ThermodynamicsTwo systems are said to be in thermal equilibrium if there is no heat flowbetween then when they are brought into contact. Temperature is the indicator of thermal equilibrium in the sense that there is nonet flow of heat between two systems in thermal contact that have the sametemperature.15.2 The Zeroth Law of ThermodynamicsTHE ZEROTH LAW OF THERMODYNAMICSTwo systems individually in thermal equilibriumwith a third system are in thermal equilibriumwith each other.15.3 The First Law of ThermodynamicsSuppose that a system gains heat Q and that is the only effect occurring.Consistent with the law of conservation of energy, the internal energyof the system changes:QUUUifHeat is positive when the system gains heat and negative when the systemloses heat.15.3 The First Law of ThermodynamicsIf a system does work W on its surroundings and there is no heat flow, conservation of energy indicates that the internal energy of the system will decrease:WUUUifWork is positive when it is done by the system and negative when it is doneon the system.15.3 The First Law of ThermodynamicsTHE FIRST LAW OF THERMODYNAMICSThe internal energy of a system changes due to heat and work:WQUUUifWork is positive when it is done by the system and negative when it is doneon the system.Heat is positive when the system gains heat and negative when the systemloses heat.15.3 The First Law of ThermodynamicsExample 1 Positive and Negative WorkIn part a of figure, the system gains 1500J of heatand 2200J of work is done by the system on its surroundings. In part b, the system also gains 1500J of heat, but2200J of work is done on the system.In each case, determine the change in internal energyof the system.15.3 The First Law of Thermodynamics(a)(b)   J 700J 2200J 1500  WQU   J 3700J 2200J 1500  WQU15.3 The First Law of ThermodynamicsExample 2 An Ideal GasThe temperature of three moles of a monatomic ideal gas is reduced from 540K to 350K as 5500J of heat flows into the gas.Find (a) the change in internal energy and (b) the work done by the gas.nRTU23WQUUUif15.3 The First Law of Thermodynamics     J 7100K 540K 350KmolJ 31.8mol 0.3232323ifnRTnRTU J 12600J 7100J 5500  UQW(a)(b)15.4 Thermal ProcessesA quasi-static process is one that occurs slowly enough that a uniformtemperature and pressure exist throughout all regions of the system at alltimes.isobaric: constant pressureisochoric: constant volumeisothermal: constant temperatureadiabatic: no transfer of heat15.4 Thermal ProcessesAn isobaric process is one that occurs atconstant pressure. VPAsPFsW Isobaric process:  ifVVPVPW 15.4 Thermal ProcessesExample 3 Isobaric Expansion of WaterOne gram of water is placed in the cylinder and the pressure is maintained at 2.0x105Pa. Thetemperature of the water is raised by 31oC. Thewater is in the liquid phase and expands by thesmall amount of 1.0x10-8m3.Find the work done and the change in internal energy.15.4 Thermal Processes  J0020.0m100.1Pa100.2385VPWJ 130J 0020.0J 130  WQU    J 130C 31CkgJ4186kg 0010.0 TmcQ15.4 Thermal Processes ifVVPVPW 15.4 Thermal Processesisochoric: constant volumeQWQU 0W15.4 Thermal ProcessesExample 4 Work and the Area Under a Pressure-Volume GraphDetermine the work for the process in which the pressure, volume, and temp-erature of a gas are changed along thestraight line in the figure.The area under a pressure-volume graph isthe work for any kind of process.15.4 Thermal ProcessesSince the volume increases, the workis positive.Estimate that there are 8.9 colored squares in the drawing.  J 180m100.1Pa100.29.8345W15.5 Thermal Processes Using and Ideal GasISOTHERMAL EXPANSION OR COMPRESSIONIsothermalexpansion orcompression ofan ideal gasifVVnRTW ln15.5 Thermal Processes Using and Ideal GasExample 5 Isothermal Expansion of an Ideal GasTwo moles of the monatomic gas argon expand isothermally at 298Kfrom and initial volume of 0.025m3 to a final volume of 0.050m3. Assumingthat argon is an ideal gas, find (a) the work done by the gas, (b) the change in internal energy of the gas, and (c) the heat supplied to the gas.15.5 Thermal Processes Using and Ideal Gas(a)      J 3400m 250.0m 050.0lnK 298KmolJ31.8mol 0.2ln33ifVVnRTW02323ifnRTnRTU(b) WQU (c)J 3400WQ15.5 Thermal Processes Using and Ideal GasADIABATIC EXPANSION OR COMPRESSIONAdiabaticexpansion orcompression ofa monatomicideal gas fiTTnRW 23Adiabaticexpansion orcompression ofa monatomicideal gasffiiVPVP VPcc15.6 Specific Heat CapacitiesTo relate heat and temperature change in solids and liquids, weused:TmcQ specific heatcapacityThe amount of a gas is conveniently expressed in moles, so we write