unit Three Chemical Reactions.ppt

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1、UnitFourChemicalReactionsTeachingAim1.Understandwhatischemicalreactions.2.Knowsomebasicchemicalreactionssuchasthereactionsbetweeninert惰性(ornoble)gasesandthereactionsbetweenNonmetals.3.DescribeinEnglishhowchemicalsreactwitheachotherTeachingDifficultandImportantPointsGraspsomebasicchemicalte

2、rmsonchemicalreactionsinEnglish.Inaddition,knowabouttheprocessandresultofchemicalreactions.CONTENTS:(1)Questionsonmainchemicalreactions.(2)IntensivereadingoftheadaptedpassageChemicalReactions(3)Explainand translatethetext(4)ExtensivereadingofmaterialsonchemicalreactionsTeachingProcedurePar

3、t1Pre-activitiesPart2While-activitiesPart3After-activitiesSpotdictationAsummaryofthephysicaland(1)________  natureoflifemustbegin,notontheEarth,butintheSun;infact,attheSun’sverycenter.ItisherethatistobefoundthesourceoftheenergythattheSunconstantlypoursoutintospaceaslightandheat.Thisenergyi

4、s (2)________  atthecenteroftheSunasbillionsuponbillionsofnucleiofhydrogenatoms(3)________witheachotherandfusetogethertoformnucleiofhelium,andindoingso,releasesomeoftheenergythatisstoredinthenucleiofatoms.TheoutputoflightandheatoftheSunrequiresthatsome600milliontonsofhydrogenbe(4)________i

5、ntoheliumintheSuneverysecond.ThistheSunhasbeendoingforseveral(5)________ofmillionsofyears.Thenuclearenergyis(6)________attheSun’scenterashigh-energygammaradiation,aformof(7)________radiationlikelightandradiowaves,onlyofverymuchshorter(8)________.1.chemical2.liberated3.collide4.converted5.t

6、housands6.released7electromagnetic8.wavelengthThisgammaradiationis(9)______________________________________________.Thisradiation,initsturnisabsorbedandreemitted.Astheenergyfiltersthroughthelayersofthesolarinterior,itpassesthroughtheX-raypartofthespectrumeventuallybecominglight.Atthisstage

7、,(10)______________________________________________,andcanescapeintospacewithoutbeingabsorbedfurtherbytheatoms.(11)____________________________________________,ithitstheEarth.9.absorbedbyatomsinsidetheSuntobereemittedatslightlylonger wavelengths.10.ithas reach