state

Definition

Whenthesystem'stemperature,pressure,volume,stateofmatter,amountofmatter,phase,variousenergies,etc.areconstant,wesaythatthesystemisinastate(state).

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,buttheworktheydoTheyarethelimitvalues​​ofexpansionworkandusefulwork.Theworkdoneinallactualprocessescannotreachorexceedtheworkdoneinthereversibleprocessnumerically.

Stateofmatter

Solid

Liquid

Gaseous

Plasma

Boaicondensedmatter

Fermioncondensedmatter

Neutronstate

Superconductingstate

Superfluidstate

Supersolidstate

Spontaneousprocessandnon-spontaneousprocess

Thermodynamicsalsodividestheprocessintospontaneousandnon-spontaneousprocesses.Spontaneousprocessesareprocessesthatoccurnaturallyinnature,andgowiththeflow;non-spontaneousprocessesareprocessesthatdonotoccurnaturally.Examplesareasfollows:

Heatflowsfromhightemperaturetolowtemperature

Waterflowsfromhighmountainstoplains

Windflowsfromhighpressuretolowpressure

Currentflowsfromhighpotential(positive)tolowpotential(negative)

Hydroxideunderpressureiscombinedintowaterandheatflowsfromlowtemperaturetohightemperature(refrigerator)

Waterflowsfromplaintomountain(pumper)

Airflowflowsfromlowpressuretohighpressure(compressor)

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Currentflowsfromlowelectricpotentialtohighelectricpotential(batterycharging)

Thedecompositionofwaterintohydrogenandoxygen(electrolysis)atnormaltemperatureandpressure

ThethermodynamicsprovethatinaclosedsystemIfaspontaneousprocessoccursintheprocess,thesystemmusthavethepossibilityofdoingusefulworktotheenvironment.Conversely,ifusefulworkmustbedonetoaclosedsystem,aprocesswilloccurinthesystem,andthisprocessmustbeanon-spontaneousprocess.

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