2019年AlkanesandAlkenes烷烃和烯烃ppt课件.ppt

《2019年AlkanesandAlkenes烷烃和烯烃ppt课件.ppt》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、KS4ChemistryAlkanesandAlkenesAlkanesandAlkenesAlkenesAlkanesSummaryactivitiesCombustionofalkanesContentsCrackingandpolymerizationBecausethemainuseofhydrocarbonsisasafuelthereisnopointingoingtotheefforttoseparatethemintoindividualhydrocarbons.Itis,however,possibletoobtainpurehydrocarbon

2、sbyverycarefuldistillation.Thissectionisaboutpurehydrocarbons.PurehydrocarbonsCarbonisanunusualatominthatitisabletoformverystrongcovalentbondswithothercarbonatoms.Whenwethenincludeitsabilitytoalsobondwithotherelementsweopenupthepossibilityofthehighlydiverseandcomplexmolecules(likeDNA)t

3、hathaveledtothepossibilityoflife.Becauseofthis,thechemistryofcarboncontainingcompoundsisoftencalledorganicchemistry.Organicchemistry:carbonThesimplesthydrocarbonsformaseriesofcompoundsknownasalkanes.Theseallconsistofcarbonandhydrogenonlyandeverycarbonhasfoursinglecovalentbonds.Hydrocar

4、bonFormulaStructureMethaneCH4EthaneC2H6PropaneC3H8ButaneC4H10hydrogencarbonAlkanesThenamesofthe4simplestalkanesaremethane,ethane,propaneandbutane.Afterthatthenamesaresystematic(likethewordsusedtodescribegeometricshapes).E.g.5carbons=pentaneC5H126carbons=hexaneC6H147carbons=heptaneC7H16

5、8carbons=octaneC8H189carbons=nonaneC9H2010carbons=decaneC10H22carbonhydrogenpentaneNamesofalkanesAlkanesallhaveverysimilarstructures.Theyallconsistofcarbonandhydrogenonlyandeverycarbonhasfoursinglecovalentbonds.TheyhaveaCH3ateachendofthemolecule.WhatdiffersisthenumberofCH2groupsbetween

6、thetwoends.ItispossibletobuildupaseriesbysimplyaddinganextraCH2groupThisleadstoageneralformulaofCnH2n+2hydrogencarbonn=1n=2n=3n=4StructureofalkanesWhatwillbetheformulaforalkanescontainingthefollowingnumbersofcarbons?C12H26C16H34C31H64C19H40NumberofcarbonsFormula12163119What’stheformula

7、?Althoughnormalchemicalformula-likeC5H12-areusedtodescribealkanes,theydonotconveywhichatomisjoinedtowhichotheratom.Togetaroundthisweoftenuseddisplayedformulaetodescribeorganicmolecules.Displayedformulaeshowwhich4atomseachcarbonisbondedto,buteventhesedonotshowtheactual3Dshapes.Forthat