University:
Mississippi College
Course:
CHE 141 | General Chemistry I
Academic year:

2022
Views:

366

Pages:

3
Author:

Abby D.

3.ThermochemistryheatThestucioloftheorievolved(given off) by chemical reactionsEnergy The capacity to do work (w=Fxd "movematter")or produce neat.PE,KEKE=onlikal(gg(s)associated w/ position or energy associated w/ movementcompositionsoule Mkgm2chemists "swotype"- thermal energy:chemists Subtype"52energy assoc wl temp. TT KEIKSChemical energy: E4movement of molecutes when they get10005hot,Contained within atomsand molecules.Key Pt: To track E changes, we must define "system US. "surroundings""system". the substance under study (cremical rxn)"surroundings" All substances with the system can exchange E.ex what is the boiling point of H2OG Titboilssurroundingpart ofxInternal engy (E) The sum total of all the KE & PE asubstance.chengeinhigh EAEEfinal - EinitialloweAE is positive - A increaseFinalinitialinitial that AE is negative -A decrease(final(small) initial (big))aka'l aw of conservationAE system =- surroundings OF energy "lst law of thermody namics"increasedecreasemeans energy cannot be created nordecrease increasesystemdestroyed it has to go somewhere, also itConsider thisranhas to be transfered.C(S)#O2(g)CO2(g)highersubstanceslower energy substance1121 cont.Ediagram:C (5) +,02(g) (CO2(g)C(S)O2(g)- negativeinitialEcreatestfromesenergyC03(g).finalXnprogressproductsE flows into the surrandingsAEsurr = positiveReverse Rxn:# O2(g)lower E substancehigher EsubstancesCCS)+ O2(g)sys - positive1Egains energyCO2(9)sysenergyflows in(xn progressfromsurroundings 4E sum = negativeHow does all this E flow bt sys & surr?4 2 ways: through neat or through workheat (q):work(w);4 the flow of energy caused4 we Fxdby atemp. diff bt. Sys & surrOheat flowsnighten atorowtempisub toncemeasured in Joules46q+wkey Primosis consider the signs (+,0)(inputs)live (neg) contputs)9system gains heatsystem loses neat(absorbs,warms, requires)(produces, releases, evolves)work is done on the systemwwork done by the systemmarker moving by you.outputtingZEsystem gains Esystem loses ECabsorbs)(reveases)E flows intosystemE flows out of the system cont.AE=oft3Anice cube melts + cools the surrounding beverage.SystemIStheEexchange:+9,-9,tw,-wtqLabsorbingeatfrommelting.?systemTheairinaninflatedballoonwarmsasitabsorbs200.0Jheat.CharlesAs it expands,it does 77.OKJ of work.LawCalc. the change in internal energy to the system.DE200.05xIKJ=q+w10003=(200.03)+6770.KJ)=(a.2000KT)(C-77.0KJ)= -76,8KJ