资源描述：
《The second Law课堂版》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。
1、TheSecondLaw ofThermodynamicsChapter1dealtwiththefirstlawofthermodynamics,theconservationofenergyandenergytransferintermsofheatandwork.Thischapterdealswithanotherthermodynamicproperties,entropy,whichisalsoastatefunction.Thefirstlawofthermodynamicsaccountsfortheenergiesinvol
2、vedinsuchaconversionbutplacesnolimitsontheamountsthatcanbeconverted.Thesecondlawisconcernedwithlimitsontheconversionof“heat”into“work”byheatengines.StatementforthesecondlawTherearequiteafewequivalentwaystostatethesecondlaw.Ifthestatementsarecorrect,theyareallequivalent.Some
3、arehardertounderstandthanothers;someareincludedonlyforhistoricalpurposes.Ithinkthefollowingwayofstatingthesecondlawisuseful.1)Everythermodynamicsystempossessesanextensivestatefunctioncalled“theentropy”whichcanbecalculatedbyareversible(thatis,aquasi-staticlimitofarealprocess
4、)pathfromanarbitrarilychosen“ReferenceState”byintegratingtheheatabsorbedbythesystemdividedbytheabsolutetemperatureofthesystem.Inotherwords,“Entropy,thestatefunction,existsforeverysystem...”2)Duringanyobservableprocess,theentropyofasystemplusitssurroundings(togetherdefininga
5、nisolatedsystemoruniverse)neverdecreases.And,inotherwords,“...anditalwaysincreasesfortheuniverse”)StatementforthesecondlawClausiusHeatisnotobservedtopassspontaneouslyfromabodyatlowtemperaturetoabodyathighertemperature.Kelvin:Itisimpossibletocontinuouslyperformworkbycoolinga
6、bodytoatemperaturebelowthatofthelowesttemperatureofitssurroundings.Ostwald:Aperpetualmotionmachine“ofthesecondkind”hasneverbeenobserved.(Aperpetualmotionmachineofthesecondkind“runsforever.”)Caretheodory:Thisisthemostelegant(andhardesttounderstandandapply,perhaps)asitrequire
7、sthefewestunderlyingassumptions.StatementforthesecondlawIntheneighborhoodofeverythermodynamicstatethatcanbereachedbyareversiblepath,thereexistsstatesthatcannotbereachedalongareversibleadiabatic(isentropic)path;or,inotherwords,whichcanbereachedeitherirreversiblyornotatall.Fi
8、nally,thesecondlaw(itisreallyanaxiom—ithasneverbeenproved;onlyneverdisproved.)LESS
