aplab#6-thermochemistryenthalpyofformationof：ap实验室#6形成的热焓

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1、APLab#9–KineticsLab–TheIodinationofAcetoneIntroductionTherateatwhichachemicalreactionoccursdependsonseveralfactors:thetypeofreactants,theconcentrationofreactants,thetemperature,andthepresenceofacatalyst.Thisexperimentwillfocusonhowconcentrationaffectsrate.Foragivenreaction,therateusuallyincreasesw

2、ithanincreaseinconcentrationofanyreactant.Howeversomereactionratesareindependentofcertainreactantconcentrations.Thesetypeofreactantsarecalledzero-order.Iftherateincreasesproportionallywithareactant,thenthereactantissaidtobefirst-order.Iftherateincreasesatanexponentialincreasethatisdoublethatofther

3、eactant,thenthereactantissaidtobesecond-order.Inthisexperiment,acetoneiscombinedwithiodineusinganacidcatalyst.Theacid,thoughacatalyst,isactuallypartofthereactionprocessandisthereforetreatedasareactant.Thereactionisasfollows:CH3-C(=O)-CH3(aq)+I2(aq)+H+(aq)àCH3-C(=O)-CH2I(aq)+HI(aq)Acetone+iodine+ac

4、idàiodo-propanone+hydroiodicacidTheratelawofthisreactioncanbewrittenas:rate=k[acetone]m[I2]n[H+]pwherekistherateconstantandm,n,andparetheordersofthereactantsforthisreaction.Theratecanbeexpressedasthedisappearanceofoneofthereactants.Sinceiodinewillbethelimitingreactantinthisexperiment,wecanexpresst

5、herateas,rate=-D[I2]/Dt.Creatingadatatableandanalyzinghowtherateofthereactionchangeswithdifferentconcentrationswilldeterminetheratelawforthisequation.Finally,therateconstantforthisreactionwillbedetermined.Notehowever,thattherateconstantisdependantontemperature,sotherateconstantwouldchangeatdiffere

6、nttemperatures.Determiningratelawscanalsobeusefulisfindingandprovingmechanismsforareaction.Attheendofthisexperiment,amechanismwillbeproposedandyouwillhavetoexplainwhytheproposedmechanismisorisnotvalidforthisreaction.ObjectiveDeterminetheratelawexpressionfortheiodinationofacetone.Determineitsrateco

7、nstantataspecifictemperature.SafetyWearprotectiveglassesatalltimes.Iodinesolutionmaystainclothes.Materials4.0Macetonesolution125-mLErlenmeyerflaskStopwatch1.0MHClsolutionSafetyglassesThermometer0.0050Miodinesolut