1第一章 热力学第一定律课堂.ppt

上一内容下一内容回主目录Chapter 1 The First Law of Thermodynamics and Thermo chemistry2023/1/27上一内容下一内容回主目录Chapter 1 The First Law of Thermodynamics and Thermo chemistryKeywords:Surroundings 环境Open system 敞开体系Closed system封闭体系Isolated system 孤立体系Extensive properties广度性质Intensive properties 强度性质Thermal equilibrium热平衡Mechanical equilibrium力平衡Phase equilibrium相平衡Chemical equilibrium化学平衡State 状态State function状态函数2023/1/27上一内容下一内容回主目录Chapter 1 The First Law of Thermodynamics and Thermo chemistryInitial state 始态Final state 终态Extract differential全微分Process 过程Path 途径Isothermal process等温过程Isobaric process等压过程Isochoric process 等容过程Adiabatic绝热Cyclic 循环的Heat 热Work 功Endothermic吸热的Exothermic放热的Internal energy内能Translational energ平动能Rotational energy转动能Vibrational energy振动能2023/1/27上一内容下一内容回主目录Chapter 1 The First Law of Thermodynamics and Thermo chemistryElectronic 电子的Absolute values绝对值Vaporize 汽化Heat capacity 热容Quasistatic process准静态过程Reversible process可逆过程Enthalpy 焓Isochoric heat定容热容Isobaric heat定压热容Molar heat capacity摩尔热容Hesss law盖斯定律Stoichiometric coefficients化学计量系数Heat of formation生成热Heat of combustion燃烧热Thermo chemical equation热化学方程Heat of solution 溶解热Kirchhoffs law基尔霍夫定律2023/1/27上一内容下一内容回主目录Contents:Chapter 1 The First Law of Thermodynamics and Thermo chemistry1.1 The Introduction of Thermodynamics1.2 Basic Definitions1.3 The first law of thermodynamics1.4 reversible process1.5 Enthalpy1.6 Heat capacity1.7 The Application of The First Law of Thermodynamics for The Ideal Gas 1.8 Heat Effect of Chemical Reaction1.9 Some Kinds of Heat Effects1.10 Kirchhoffs Law2023/1/27上一内容下一内容回主目录Thermodynamics is a science that studies the rules of energy transformation.Applying the basic principles of thermodynamics into the relative study of chemical process,it formed chemical thermodynamics.1.The research object and content of thermodynamics 1.1 The Introduction of Thermodynamics2023/1/27上一内容下一内容回主目录methods：macro-approach，not consider the detail of change，as long as confirm the initial state and final state,the relevant calculation can be carried out.only study the probability and limit of system change,not consider the reality of change,not involve time,not able to estimate the mechanism and rate of changes.2.The methods of thermodynamics and its limitation 1.1 The Introduction of Thermodynamics2023/1/27上一内容下一内容回主目录1.System and SurroundingsSystem（系统（系统）:surroundings（环境（环境）:systemsurrounding1.2 Basic Definitionsthe part of the universe under studythe parts of the universe that can interact with the system.2023/1/27上一内容下一内容回主目录（1 1）open system（敞开系统（敞开系统）it has matter and energy transfer between sys.and surr.1.2 Basic Definitions According to the relationship between system and surrounding,the systems can be divided into three types:2023/1/27上一内容下一内容回主目录（2 2）closed system（封闭系统封闭系统）1.2 Basic DefinitionsIt has no matter transfer,but has energy transfer between sys.And surr.2023/1/27上一内容下一内容回主目录（3 3）isolated system（隔离系统（隔离系统）it has no energy and matter transfer between sys.and surr.1.2 Basic Definitions2023/1/27上一内容下一内容回主目录2.properties of system1)extensive properties（广度量广度量）性质的数值与系统的物质的性质的数值与系统的物质的数量成正比数量成正比。这种性质具有这种性质具有加和性加和性。2)intensive properties（强度量（强度量）性性质质的的数数值值与与系系统统中中物物质质的的数数量量无无关关，不不具具有加和性有加和性V1,T1V2,T2V=V1+V2T T 1+T 21.2 Basic Definitions3)connection3)connection2023/1/27上一内容下一内容回主目录3.Thermodynamics equilibriumwhen the properties of system dont change with time,the system is in thermodynamic equilibrium.thermal equilibrium（热平衡热平衡）mechanical equilibrium（力学平衡力学平衡）1.2 Basic Definitionsphase equilibrium（相平衡相平衡）chemical equilibrium（化学平衡化学平衡）Thermodynamics equilibrium2023/1/27上一内容下一内容回主目录4.State and state function1)state（状态状态）the sum of all properties of system.Described by T，P，V，etc.Initial state Final state 1.2 Basic Definitions2023/1/27上一内容下一内容回主目录2)state function（状态函数状态函数）:all macroscopic properties are called state functions.1.2 Basic DefinitionsFeatures:Uniform function:has fixed value dx is total differential in mathematicsaggregation of state functions is also state function.2023/1/27上一内容下一内容回主目录5.Process and pathstate1State2path 1path 2(T1，p1)(T2，p2)1)process(过过程程):the state change process of system from the initial state to the final state.2)path(途径途径):specific steps which finish a process.1.2 Basic Definitions2023/1/27上一内容下一内容回主目录系统变化过程的类型系统变化过程的类型：（1）simple state change(pure pVT change)（2）phase change（3）chemical change1.2 Basic Definitions isothermal process：T1=T2=Tex isobaric process：P1=P2=Pex isochoric process：V1=V2 adiabatic process：Q=0 cyclic process：P=0，T=0，U=0.free expansion process：Pex=0P.V.T change2023/1/27上一内容下一内容回主目录Q0Q0Surr.does work on sys.，WVs)If regard the CO2 as ideal gas,thenW=PV(CO2)nRT18.31411739752 JQW1789.752 168.25 kJ solute：T=constant and P=constant：2023/1/27上一内容下一内容回主目录the concept of heat capacityMean heat capacity 1.6 Heat capacitySpecific heat capacity:heat capacity of 1kg substance.J.K-1.Kg-1Molar heat capacity:heat capacity of 1mol substance.J.K-1.mol-1Heat capacity:the heat absorbed when the temperature of system rises 1(or 1 K)2023/1/27上一内容下一内容回主目录 if Cv，m=constant1.6 Heat capacityHeat capacity at constant volume2023/1/27上一内容下一内容回主目录Heat capacity at constant pressure if Cv，m=constant1.6 Heat capacity2023/1/27上一内容下一内容回主目录 Heat capacity temperature 1.6 Heat capacity2023/1/27上一内容下一内容回主目录Examples【example 1-4】Under 101.325KPa,the temperature of 1mol O2 increases from 298K to 473K,calculate QP.【example 1-5】at 1.01325Pa,2mol 50 H2O(l)150 H2O(g)calculate QP.2023/1/27上一内容下一内容回主目录Internal Energy and Enthalpy of Ideal Gasanalysis:analysis:T invariable invariable,Q0;free expansionfree expansion,P Pe e=0 =0 W0;so so U=0.1.7 The Application of The First Law of Thermodynamics for The Ideal Gas 2023/1/27上一内容下一内容回主目录Ideal gas:U=f(T)H=f(T)1.7 The Application of The First Law of Thermodynamics for The Ideal Gas Ideal gas CV=f(T)CP=f(T)Conclusion:2023/1/27上一内容下一内容回主目录再由再由1.7 The Application of The First Law of Thermodynamics for The Ideal Gas CPCV of ideal gas2023/1/27上一内容下一内容回主目录Isobaric 1.7 The Application of The First Law of Thermodynamics for The Ideal Gas For ideal gasFor liquid or solid system For 1mol ideal gas2023/1/27上一内容下一内容回主目录1.7 The Application of The First Law of Thermodynamics for The Ideal Gas Ideal gasMonatomic molecule:Diatomic molecule:Polyatomic molecule:2023/1/27上一内容下一内容回主目录 U=0，H0;Q -W;in reversible cycle:QR=-WR=0Isothermal irreversible cycle：QIR=-WIR0 Isothermal process of Ideal Gas1.7 The Application of The First Law of Thermodynamics for The Ideal Gas 2023/1/27上一内容下一内容回主目录Q=0,dU=W1.Equation of adiabatic reversible process Adiabatic process of Ideal Gas1.7 The Application of The First Law of Thermodynamics for The Ideal Gas 2023/1/27上一内容下一内容回主目录1.7 The Application of The First Law of Thermodynamics for The Ideal Gas adiabatic exponent2023/1/27上一内容下一内容回主目录2.Adiabatic work1.7 The Application of The First Law of Thermodynamics for The Ideal Gas 2023/1/27上一内容下一内容回主目录1.7 The Application of The First Law of Thermodynamics for The Ideal Gas 2023/1/27上一内容下一内容回主目录=nCV,m(T1-T2)理想气体绝热理想气体绝热=0 恒容恒容;自由膨胀自由膨胀;凝聚体系凝聚体系(V 0)P-V work calculation(summary)Homework:P47 2;P47 32023/1/27上一内容下一内容回主目录Contents:、isochoric reaction heat and isobaric reaction heat、thermo chemical equation、Hesss law1.8 Heat Effect of Chemical Reaction2023/1/27上一内容下一内容回主目录isochoric reaction heat and isobaric reaction heatIsobaric reaction heat:Isochoric reaction heat:Reaction heat:if a closed system can do only P-V work,there is a chemical reaction,when the temperature of productions are same as that of reactants,the heat absorbed or sent out of the system is called heat effect of reaction,also is called reaction heat.QV=U=(U)production(U)reactantrQP=Hr=(H)production(H)reactant2023/1/27上一内容下一内容回主目录Reactant T1,p1,V1For ideal gas:isochoric reaction heat and isobaric reaction heat rH1=QPProduction T1,p1,V2Isobaric:(1)Production T1,p2,V1Isochoric:rU2=QV rH2(2)For liquid or solid:Qp=QV H3(3)Qp=QV +n RT r H1=r H2+H3=r U2+(PV)2+H3(PV)2=(PV)2,final(PV)2,initial2023/1/27上一内容下一内容回主目录Example：Under the condition of 298.2K,in a closed container,the n-heptane C7H16 combustion,known as QV=-4.807106J.mol-1,calculate QP.Solute:C7H16(l)+11O2(g)=7CO2(g)+8H2O(l)n=7-11=-4Qp=QV +n(g)RT=-4.807 106-4 8.314 298.2=-4.817106J.mol-12023/1/27上一内容下一内容回主目录1.state of aggregation:g,l,s,aq thermo chemical equationEndothermic reactionExothermic reaction2.heat effect3.condition4.heat effect expression of equation(2)1/2N2(g)+3/2H2(g)NH3(g)rHm=-46.11kJ.mol-1(1)N2(g)+3H2(g)2NH3(g)rHm=-92.22kJ.mol-1(5)H2(g)+I2(g)2HI(g)rHm=-9.44kJ.mol-1(3)H2(g)+I2(s)2HI(g)rHm=53.0kJ.mol-1(4)2HI(g)=H2(g)+I2(s)rHm=-53.0kJ.mol-1rHm0rHm02023/1/27上一内容下一内容回主目录 Hesss lawa reaction goes by no matter one step or some steps;the heat effect is always same.That is to say,under the condition of isochoric process or isobaric process,the heat reaction is only relative with initial and final states.Hesss law：Hess Hess2023/1/27上一内容下一内容回主目录Example：C(s)CO2(g)+O2(g)rHm(1)CO(g)rHm(2)+1/2O2(g)+1/2O2(g)rHm(3)C(s)+O2(g)=CO2(g)(1)C(s)+1/2O2(g)=CO(g)(2)CO(g)+1/2O2(g)=CO2(g)(3)?Calculate the rHm of the reaction C(s)+1/2O2(g)=CO(g)rHm(1)=-393.5kJ.mol-1rHm(3)=-283.0kJ.mol-1rHm(2)=2023/1/27上一内容下一内容回主目录1.9 Some Kinds of Heat EffectsQP=Hr=(H)production(H)reactantContainer A:CO(g)O2(g)CO2(g)Container B:CO(g)H2(g)CO2(g)H2O(g)Standard state：pure liquid,pure solid and has properties of ideal gas of pure gas at pressure pand temperature T.2023/1/27上一内容下一内容回主目录heat of formationStandard molar enthalpy of formation:For example：at 298.15 K标准摩尔生成焓标准摩尔生成焓2023/1/27上一内容下一内容回主目录Steadiest elementary substancep,T H1 H2a A+d D p,T g G+h H p,T Initial stateFinal stateheat of formation2023/1/27上一内容下一内容回主目录-74.8 0 -393.5 -285.3-393.5+2(-285.3)-(-74.8)=-889.3kJ.mol2(-285.3)-(-74.8)=-889.3kJ.mol-1-1Solute:CH4(g)+2O2(g)CO2(g)+2H2O(l)【example 1-10】Calculate the reaction heat of reactionCH4(g)+2O2(g)CO2(g)+2H2O(l)at 298.15K and 101325Pa.heat of formation2023/1/27上一内容下一内容回主目录 heat of combustionStandard molar enthalpy of combustionAppointed productions are regulated as：标准摩尔燃烧焓标准摩尔燃烧焓CCO2（g）ClHCl（aq）SSO2（g）HH2O（l）NN2（g）metalLiber state2023/1/27上一内容下一内容回主目录For example：in standard state,at 298.15K,C2H5OH(l)+3O2(g)=2CO2(g)+3H2O(l)heat of combustion2023/1/27上一内容下一内容回主目录Steadiest Combustion productionp,T H1 H2a A+d D p,T g G+h H p,T Initial stateFinal state heat of combustion2023/1/27上一内容下一内容回主目录【example 1-10】At the standard pressure and 298.15K,（2）the of cyclopropane isomerism into propene at 298.15K（1）the of cyclopropane at 298.15K Known as:C(graphite)=-393.5kJ.mol-1H2(g)=-285.3kJ.mol-1C3H6（cyclopropane)=-2091kJ.mol-1(propene)=20.6kJ.mol-1环丙烷环丙烷丙烯丙烯 heat of combustion2023/1/27上一内容下一内容回主目录Solute:（1）the generating reaction of cyclopropane is：3C（graphite）+3H2（g)C3H6（cyclopropane）=3(-393.5)+3(-285.3)-1(-2091)（2）the reaction that cyclopropane isomerism into propene is：C3H6（cyclopropane）=CH3CH=CH2 heat of combustion2023/1/27上一内容下一内容回主目录 heat of solutionHeat of solutionintegral heat of solution differential heat of solution solvent2023/1/27上一内容下一内容回主目录1.10 Kirchhoffs Law1.Differential form:2.Integral form:constant2023/1/27上一内容下一内容回主目录1.10 Kirchhoffs Law2023/1/27上一内容下一内容回主目录【example 1-13】C6H12O6(s)+6O2(g)6H2O(l)+6CO2(g)O2(g)=29.36CO2(g)=37.13H2O(g)=75.30C6H12O6(s)=218.9Suppose =constant,calculate of this reaction.Known as:1.10 Kirchhoffs Law2023/1/27上一内容下一内容回主目录=675.30+637.13218.9629.36 Solute：1.10 Kirchhoffs Law2023/1/27上一内容下一内容回主目录【example 1-14】N2(g)+3H2(g)=2NH3(g)Known as:=-92.22kJ.mol-1 J.K-1.mol-1 J.K-1.mol-1 J.K-1.mol-1 Try to calculate of this reaction.1.10 Kirchhoffs Law2023/1/27上一内容下一内容回主目录Solute:1.10 Kirchhoffs Law2023/1/27上一内容下一内容回主目录Summary:conversanceunderstandHomework:P 49:14,17 P 50:22参考参考http:/202.112.154.83/zskj/2015/wuhua/chapter1/brief/index.html物化物化2023/1/27