无机化学无机化学英文PPT (22).ppt

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1、Chapter 13.p-block elements(II)13.2 Oxygen-group elements13.1 Nitrogen-group elements13.1.Nitrogen-group elements1.Overview(know)Nitrogen-group(VA)：N,P,As,Sb,BiAsSbBiOuter electron configuration：ns2 np3It shows a variety of valence states mainly+3 and+5.Nitrogen is a colorless,odorless and tasteless

2、 gas.The boiling point is-195.8 oC,slightly soluble in water.At room temperature,its chemical properties are very inactive.When heated,it can ract with the active metal,such as Li,Ca,Mg,etc.to form ionic compounds.2.Elemental Nitrogen(know)Np p:N:VB N 2s2 2px 1 2py 1 2pz1 s s p p p p 2s2 2px 1 2py 1

3、 2pz1 Which is1 1 +2 3.Nitrogen compounds1.Nitrogen hydrides(understand)(1)Ammonia:NH3(2)Hydrazine:N2H4,rocket fuel.H(N2H4,L)=-622 kJmol-1Solidifying point:1.4,boiling point:113.5(3)Hydroylamine:NH2OH,reduction agent Nitrogen and water(4)Ammmonium salt:NH4+,NH4NO3 as fertilizers and explosives(NH4)2

4、SO4 as fertilizers(5)hydragoic acid and its hydrazoates.:HN3,explosive 2.The nitrogen hydrideNH3N2H4HN3NH2OHAmmoniaHydrazineHydragoic acidOxyammonia(1)NH3 Preparation of ammoniaindustriallaboratory The structure of ammonia moleculenitrogen mainly uses sp3 hybridization Ammonia molecular structure mo

5、del Physical propertiescolorless,stimulating gas,liquid ammonia can be used as refrigerant and solvent,slightly soluble in water.The freezing point,boiling point,heat of fusion,and solubility are all higher than the hydrides of other elements in this group.The characteristics of NH3：Strong polarity,

6、ease form hydrogen bondsLow oxidation number,lone-pair electrons100.8pm107.3oe.g.:NH3+H2O NH4+OH-Add H+-generate ammonium salt Add OH-release NH3(Used for laboratory synthesis of NH3,identification of NH4+salt)Ag+2NH3 Ag(NH3)2+Cu2+4NH3 Cu(NH3)42+CaCl2+8NH3 CaCl28NH3 (CaCl2 cannot be used as a desicc

7、ant for NH3）The chemical properties of ammonia(1)Addition reaction Ammonia,as Lewis base,provides lone pair of electrons and react with other molecular additions(2)Substitution reactionsProduce a series of ammonia compoundsFor example：NaNH2、Li2NH、AlN;Hg(NH2)Cl、CO(NH2)2Soluble in water to form a weak

8、 base.catalyst2NH3+2Na NaNH2+H24NH3+COCl2 CO(NH2)2+2NH4Cl2NH3+HgCl2 Hg(NH2)Cl +NH4Cl 4NH3+3O2(Pure oxygen)2N2+6H2O 4NH3+5O2 4NO+6H2O(The basic reaction of industrial HNO3)2NH3+3CuO 3Cu+N2+3H2O 2NH3+3Cl2 N2+6HCl (Can be used to check whether the Cl2 gas pipeline is leaking)(3)Reduction reaction400800

9、PtNH4NO3 N2O+2H2O The chemical properties of ammonia Ammonia salts Some properties of NH4+are similar to that of alkali metal ions(K+),leading to some similarities in their corresponding salts.Such as:crystal form,color,solubility.Thermal decomposition of solid ammonium salt:It is different from the

10、 salt corresponding to the alkali metal ion,such as:ammonium salt is hydrolyzable and thermally unstable.a.Ammonium salt of non-oxidizing acid；The thermal decomposition products of solid ammonium salts depends on the nature of the acid radical):(NH4)2CrO7producesgasandgreenCr2O3inthethermaldecomposi

11、tionreactionb.Ammonium salt of oxidizing acid:N2ornitrogenoxides(DoesnotreleaseNH3)The identification of NH4+:a.NH4+OH-NH3+H2O(identifiedbylitmuspaper.)b.NH4+Nesslersreagent K2HgI4KOH solutionO3H7II(s)NHHgHgO4OH2HgINH22244+-+reddish brown to dark brown.hydrazine,hydroxylamine,hydroazic acid（2）The de

12、rivatives of ammonia hydrazinehydrazine（hydrazinehydrazine）N2H4synthesis 2NH3+NaClO N2H4+NaCl+H2OThe reaction is divided into two steps,trace transition metal ions will affect on the formation of hydrazineProperties：binary proton baseform complexesStrong reducing agent(under alkaline)N2H4(l)+O2(g)N2

13、(g)+2H2OAlkaline：NH3 N2H4 NH2OH hydroferroic acid HN3synthesis Hydrazine reacts with nitrous acid to generate hydrogen azide acidN2H4+HNO2 HN3+2H2OProperties Its vulnerable to impact and explosive：2HN3（g）3N2(g)+H2(g)r rHm =-527 kJ.mol-1The structure of hydrazide acid and its ionNNNHNNN It produces w

14、eak acid.HN3（aqaq）H+N3-Ka=1.91010-5 Its dilute aqueous solution hardly decomposes.AzideThe azide of heavy metals is(AgAg+,PbPb2+,CuCu2+,HgHg22+)easily decomposed by impact and can be used as a detonator hydroxylamine NH2OHMolecular StructurePropertiesbinary proton base（weak base）Alkaline：NH3 N2H4 NH

15、2OHStrong reducing agent(under alkaline)2NH2OH+2AgBr 2Ag+N2+2HBr+2H2O 2.Nitrogen oxides(grasp)(grasp)NOismainlyproducedbynaturelighting.N2+O2=2NOAnotherisautomobileexhaustNOtoxicity:FormscomplexeswithFe2+inthebloodtocausepoisoningThenitricoxiderunsintheatmospheretothestratosphereanddestroysozonevery

16、seriously.CatalyticoxidationmethodforremovingNOandCOfromexhaustgascatalyst.Whenthegasisremoved,itisadsorbedonthecarrierandcatalyzesoxidationtogenerateCO2(1)Nitrogen oxides The oxidation number of N can be from+1 to+5,and 5 kinds of oxides can be formed：N2ONON2O3NO2N2O5nitrogen peroxide Nitric oxide

17、dinitrogen trioxidenitrogen dioxidenitrogen pentoxide(nitric anhydride)Molecular Structure MO：NO（1）2（2）2（3）2（4）2（1）4（5）2（2）1 bond order =（6-1）2 =2.5 Physical properties Weak polarity（=0.17D）paramagnetic Odd electron compound。Nitric oxide NO Chemical properties:N O Give(2*)1anti-bondedelectron，3eGivealonepairofelectronsonNDonor 2NO(g)+CO(g)=2N2(g)+2CO2(g)rG=-687.2 kJ.mol-1 dimer 2 NO =(NO)2oxidation-reduction quality：A:Reducibility：5 NO+3MnO4-+4H+=5NO3-+2Mn2+3H2O (can be used to determine NO)2NO+O2 =2NO2B:Oxidizability：Coordination properties：