高中化學(xué)第四章知識(shí)點(diǎn)(Highschoolchemistry1chapter4knowledgepoints)

1、高中化學(xué)必修1第四章知識(shí)點(diǎn)(Highschoolchemistry1chapter4knowledgepoints)ThefourthchapterThefirstsectionofsiliconInnature,siliconisintheformofsilicaandsilicates,andthereisnosuchthingassiliconThepropertiesofsilicondioxide:highmeltingpoint,largehardnessandinsolubleinwater1.Silicaisacidicoxide:canreactwithalkalioralk

2、alineoxideSiO2naoh+2=Na2SiO3+H2OTheformationofsodiumsilicateismoreviscous,sotheglassreagentoftheacidsolutionisnotusedfortheglass,andtherubberplugisusedSiO2+CaO=CaSiO3HydrofluoricacidistheonlyacidthatreactswithsilicondioxideSiO2+4HF=SiF4arrow+H2OHydrofluoricacidcancorrodetheglassandcanbeusedtosculptt

3、heglass,whichcantbeusedinglassreagentbottles,butplasticbottles.Applicationofsilica:fiberoptics,silicon,glass,handicraft(quartz,crystal,agate)Thepreparationofsilicicacid:Na2SiO3+2HCl=2NaCl+H2SiO3SilicicacidisawhitecolloidalsolidthatisinsolubleinwaterandismoreacidicthancarbonatedTothesodiumsilicatesol

4、ution,thecarbondioxideisformedinwhitesilicateNa2sio3+CO2+H2O=Na2CO3+H2SiO3SilicagelcanbedesiccantafterdehydrationTheaqueoussolutionofsodiumsilicateiscalledwaterglass,whichcanbeusedassoapfiller,woodfireretardantandadhesive.Note:thewaterglass(i.e.,sodiumsilicatesolution)issensitivetotheCO2reactioninth

5、eairandproducesH2SiO3.ItshouldbesealedandpreservedApplicationofsilicate:ceramic,glassandcementSimplesilicon:properties:metallicblacksolidwithmetallicluster,highmeltingpoint,highhardness,stableatnormaltemperatureMethod:NormaltemperaturecanreactwithalkalisolutionandHFSi+naoh+2H2O+2=Na2SiO3h2writeSiplu

6、s4HF=SiF4+2H2USES:Semiconductormaterials,photovoltaic(computerchips,semiconductortransistors,)Sectioniitheelementofenrichmentinseawater-chlorineThepresenceofchlorine:innaturechlorineexistsmainlyinseawater,mainlyinCl-form.Physicalpropertiesofchlorinegas:agaswithapungentsmellandpoisonousyellowandgreen

7、,Itissolubleinwater(1:2),lowtemperatureandeasytoliquefywhenpressurized.Chemicalpropertiesofchlorinegas:chlorinegasandmetalreactions2Na+Cl2=2NaCl(yellowflame,whitesmoke)Cu+Cl2=CuCl2(palmyellowsmoke,asmallamountofwaterwithagreensolution,suchasalargeamountofwaterinblue)2Fe+3Cl2=2FeCl3(notgeneratingFeCl

8、2)(brownsmoke)chlorinegasandnonmetallicreactionsH2+Cl2=2HCl(whitefog)(explosionunderlightofCl2andH2)2P+3Cl2(asmallamount)=2PCl3(whitefog)(whitesmokewhenchlorineandParelit)2P+5Cl2(lots)=2PCl5(whitesmoke)(combustion:theintensechemicalreactionofanyglowingheatiscalledcombustion.Combustiondoesnothavetobe

9、oxygentoparticipate.ThenatureofcombustionistheREDOXreaction.)chlorineandwaterCl2+H2OHCl+HClO(Cl2dobothoxidantandreducingagent)Hypochlorousacid(HClO)unaryweakacid(acidisweakerthancarbonicacid),strongoxidation(sterilization,disinfection),bleaching,unstableandeasytodecompose.2HClO=2HCl+O2Newchlorinewat

10、ercomposition(particle):Cl2,H2O,HClO,H+,Cl-,ClO-Chlorinewatercomposition(particle):H2O,H+,Cl-Drychlorinegasisnotbleached,andtheessenceofbleachingisHClOinchlorinewater.thereactionwithabasesolutionCl2+2OHminus=Cl-+ClO-+H2O(usingsodiumhydroxidetoabsorbexcessCl2)Theingredientsofbleach,CaCl2andCa(ClO)2Th

11、eactiveingredientofbleachingpowder,Ca(ClO)2Bleachingprincipleofbleachingpowder:theprocessofproducinghypochlorousacidbycontactwithCO2intheair.Reactionofchlorinegastoothercompounds(strongoxidant):ReductivesubstancessuchasFe2+,Br-,I-,SO2,SO32-.Thesubstancecanbeoxidizedbychlorinegas.2fecl2+Cl2fecl3=22na

12、br+nacl+Br2Cl2=22nai+Cl2nacl+I2=2H2S+Cl2=S+2HCLNa2SO3+H2O+nacl+-H2SO4Cl2=2LaboratorypreparationofchlorinegasSection3oxidesofsulfurandnitrogenSulfur:yellowpowder,insolubleinwater,solubleinalcohol,solubleinCS2.Sandmetalreactwithmetalsulfide(suchasCu2S,FeS,etc.)SO2:colorless,pungentandpungent,noxiousga

13、s,withadenserthanair,easytoliquefy,easytodissolveinwater,1volumeofwaterdissolvedin40volumesofSO2.ItstheacidanhydrideofH2SO3.SO2+H2OH2SO3SO2+Ca(OH)2=CaSO3+H2OThebleachingofSO2makesthemagentacolorfade,thenon-oxidizedreductionreaction,temporary,canonlymakethepurplelitmustestliquidred,cannotmakeitfade.S

14、O2canbeusedtokillbacteria.TheweakoxidationofSO2:SO2+2H2S=3S+2H2OStrongreducibilityofSO2:SO2+Br2+2H2O=H2SO4+2HBr(discolorationofbromine)SO2+Cl2+2h2o+2=-H2SO4HCL(SO2withchlorinewaterintothecoloredsolutionsuchasmagenta-bleaching,ornobleaching)5SO2+2KMnO4+2H2O=K2SO4+2MnSO4+2H2SO4(notmemory)(knowingthatS

15、O2candiscolortheKMnO4solution,SO32-withH+,KMnO4-cantcoexistinthesolution)SO2+O2SO3SO2test:applySO2tobromine,KMnO4solutionandmagentasolutiontoseeifitfades.Remove(SO2orHClgas)fromCO2andusesaturatedNaHCO3solutionCheckforCO2andSO2inthemixtureofgases:firstthroughmagenta-thenthroughKMnO4-throughmagenta-an

16、dthenpassthroughtoclarifythelimewater.SO2onlyreactswithBa(NO3)2solutionandproduceswhiteprecipitation.ItdoesntreactwithBaCl2.3SO2+3Ba(NO3)2+2H2O=3BaSO4+4HNO3+2NO(theequationdoesnothavetoberemembered)Redandbrownpungentsmellpoisonousgas,denserthanair,easytoliquefy,easytodissolveinwaterThevalenceofN:-3,

17、0+1+2+3+4+5N2O5istheanhydrideofHNO3,andN2O3istheanhydrideofHNO2,4no2+2h2o+O2=4hno34noO2+2h2o+3=4hno3Thefourthsulfuricacid,nitricacidandammoniaDilutesulfuricacidwithacidity:withacid-baseindicatorandreactivemetalreactiontogenerateH2,whichreactswithmetaloxidetoformsaltandwater,Thesaltreactionproducesan

18、otheracidandsalt(thestrongacidweakacid)andneutralizesthebaseStrongH2SO4andHNO3reactwithmetalbutnotH2.Concentratedsulfuricacid:concentratedsulphuricacidisacolorlessoilliquid.Sulfuricacidisastrongacidwithhighboilingpoint,whichiseasytodissolveinwaterandcanbemixedwithwateratanyrate.Concentratedsulfurica

19、cidwillgiveoffalotofheatwhendissolvedinwater.ItcanbeusedtodryH2,O2,N2,CO,CO2,CH4,SO2,HCl,Cl2,etc.,whichcannotbeusedtodryNH3,H2S,HIandHBr.Strongoxidizing:metalsandnonmetalsthatcanbeoxidized.2H2SO4(thick)+Cu=CuSO4+2h2o+SO22H2SO4(thick)+C=CO2+2SO2+2H2O(howtotestthegasproduced,seethepreviousSsection)Nit

20、ricacid:1instability:(easytodecompose)4HNO3=4NO2arrow+2H2O+O2arrowStrongoxidation4HNO3(thick)+Cu=Cu(NO3)2+2NO28HNO3(dilute)+3Cu=3Cu(NO3)2+2NOupUndernormaltemperature(cold)thickH2SO4orstrongHNO3willmaketheactivemetalpassivate(suchasaluminumandiron),sotheirontankcanbeusedtotransportthickH2SO4orstrongHNO3.Ammonia:Physica