Определение
Когато температурата, налягането, обемът, състоянието на материята, количеството на материята, фазата, различните енергии и т.н.са постоянни, ние казваме, че системата е в състояние (състояние).
Whenthesystemchangesfromonestate(initialstate)toanotherstate(finalstate),wesay:aprocesshasoccurred.Theprocessinwhichthetemperaturesoftheinitialstateandthefinalstateareequaliscalledanisothermalprocess.Theprocessinwhichthepressuresoftheinitialstateandthefinalstateareequaliscalledanequalpressureprocess.Theprocessinwhichthevolumeoftheinitialstateandthefinalstateareequaliscalledanisovolumetricprocess.
Idealizationisanimportantscientificmethod.Whenstudyingactualgases,idealgasescanbeused.Thestudyofmechanicscanalsorelyonanidealprocesswithoutfriction.Thermodynamicsalsoassumesanidealprocess,calledareversibleprocess.Areversibleprocessisaprocessthatapproachestheequilibriumstateinfinitely.Thereversibilitymentionedhereisnotaprocessofbothforwardandreverse,whichiscommonlyunderstood,butfromtheinitialstatetothefinalstate,andthenfromthefinalstatetotheinitialstate,acycle,whichisgoodforthesystemandtheenvironment,withoutleavingbehindAny"trace".Whatis"trace"?Thisisexactlywhatwewanttofigureout,anditwillbeexplainedslowlybelow.Wejustwanttosayherethatthisthermodynamicallyreversibleprocessisanidealprocess,justastheactualgasisnotanidealgas,andjustastheactualprocessofdoingmechanicalworkdoesnothaveanyfrictionanddoesnotexist,thedischargeoftheprimarybatteryisimpossible.Littleelectricenergyisnottransformedintothermalenergy,etc.,like"idealization".Allactualprocessesareirreversibleprocesses.Theidealthermodynamicallyreversibleprocessdoesnotexist,butitisalimitprocess,whichisextremelymeaningfulfordiscussingthermodynamics.
Therearetwoidealprocessesinthermodynamics,oneisthereversibleexpansionofanidealgas,andtheotheristhereversibledischargeofthegalvanicbattery.Theyarebothidealprocessesandcannotreallyexist,buttheworktheydoTheyarethelimitvaluesofexpansionworkandusefulwork.Theworkdoneinallactualprocessescannotreachorexceedtheworkdoneinthereversibleprocessnumerically.
Състояние на материята
Твърди
Течност
Газообразен
плазма
Boai кондензирана материя
Фермионна кондензирана материя
Неутронно състояние
Свръхпроводящо състояние
Суперфлуидно състояние
Супертвърдо състояние
Спонтанен процес и неспонтанен процес
Thermodynamicsalsodividestheprocessintospontaneousandnon-spontaneousprocesses.Spontaneousprocessesareprocessesthatoccurnaturallyinnature,andgowiththeflow;non-spontaneousprocessesareprocessesthatdonotoccurnaturally.Examplesareasfollows:
Топлината преминава от висока температура към ниска температура
Води текат от високите планини в равнините
Вятърът тече от високо налягане до ниско налягане
Токът тече от висок потенциал (положителен) към нисък потенциал (отрицателен)
Hydroxideunderpressureiscombinedintowaterandheatflowsfromlowtemperaturetohightemperature(refrigerator)
Водни потоци от равнина към планина (помпа)
Airflowflowsfromlowpressuretohighpressure(compressor)
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Currentflowsfromlowelectricpotentialtohighelectricpotential(batterycharging)
Thedecompositionofwaterintohydrogenandoxygen(electrolysis)atnormaltemperatureandpressure
ThethermodynamicsprovethatinaclosedsystemIfaspontaneousprocessoccursintheprocess,thesystemmusthavethepossibilityofdoingusefulworktotheenvironment.Conversely,ifusefulworkmustbedonetoaclosedsystem,aprocesswilloccurinthesystem,andthisprocessmustbeanon-spontaneousprocess.