ATasteofThermodynamic’sandReactionRates：一味的热力学和反应速率

《ATasteofThermodynamic’sandReactionRates：一味的热力学和反应速率》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、ATasteofThermodynamicsandReactionRatesNatureofEnergyEnergy–theabilitytodoworkorproduceheat.TwobasicformsofenergyPotential–storedenergyKinetic-energyofmotionLawofConservationofEnergyEnergycanbeconvertedfromoneformtoanother,butcannotbecreatedordestroyed.Alsoknownasthe1stlawofThermodynamic

2、s.HeatversusTemperatureTemperatureisanindicationofthekineticenergyofanobject.Italsoletsyouknowwhichwaytheenergywillflowinrelationtothesurroundingobjects.Ifanobjecthasahighertempthanitssurrounding,energywillflowoutoftheobjecttothesurroundings.Ifanobjecthasatemplowerthanitssurroundings,en

3、ergywillflowintotheobject.HeatHeatisthemeasureoftheamountofenergy.ACalorieisthemetricunitofheat.ItistheamountofheatneededtoraisethetemperatureofonegramofwateronedegreeCelsius.TheSIunitisaJoule.1calorie=4.184JoulesSpecificHeat-theamountofheatneededtoraisethetemperatureofonegramofthatsubs

4、tanceonedegreecelsius.AdietaryCalorie,withacapital“C”isactuallyaKilocalorie.Soa2000Caloriedietisreallya2,000,000caloriediet.SohowdowemeasureCalories?CalorimeterBecauseweknowthedefinitionofacalorie,themassofthewaterinthecalorimeterandthetemperaturechange.Wecancalculatethenumberofcalories

5、produced.q=cxmx∆TThewaythebookwritesit.IpreferΔH=cxmxΔTBecauseyoucan’treallymeasureheatcontent,onlytheheatchange.IlikeΔHaschangeinheat.Cisthespecificheatofwater.Misthemassofthewater.ΔTisthechangeintemperature.Seesampleproblemonpage524HeatofReactionRememberHeatofsolutionfromlastchapter?H

6、eatofreactionisjustlikeit,theenergychangethattakesplaceduringachemicalreaction.(+)heatofrx=endothermic(-)heatofrx=exothermicPotentialEnergyDiagramPotentialEnergyDiagramIINote:relatetoheatandcoldpacksRatesofreactionHowfastorhowslowareactionproceeds.ThiscanbeexplainedusingamodelcalledtheC

7、ollisionTheoryCollisionTheoryLiketwocarsinaverylargeparkinglotslowlyandrandomlymovingaround.Whatisthelikelyhoodthattheywillreactwitheachother?Theyhavetofindeachother,makecontact,whichishardenough,andatthecorrectorientationtocauseanaccidentthatwillexceedtheinsurancedeductible(th