无机化学双语教学 备课资料 2006年2月 第1页 2006-02-22
第 1 页 2006-02-22 1 无机化学双语教学 备课资料 2006 年 2 月
Chapter One Nitrogen Family(Group V) Central contents 1. Know the general properties of elements of the nitrogen group and inert electron pair effect 2. Know the reactions of ammonia, understand the thermal decomposition trend of ammonium salts 3. Know the properties of nitrous acid and nitrites; understand the structure of nitric acid and nitrate radical; understand the thermal decomposition trend of nitrates 4. Know well the properties of phosphoric acid and phosphates 5. Know the properties of oxides of As, Sb, Bi and their hydrates; understand the properties of sulfides ofAs, Sb, Bi, know the trends of these compounds 6. Understand the properties of the salts of As, Sb, Bi 7. Understand the identification methods for NH4. NO2:. NO3. PO4and Bi'+ 第2页 2006-02-22
第 2 页 2006-02-22 2 Chapter One Nitrogen Family (Group Ⅴ) Central contents: 1. Know the general properties of elements of the nitrogen group and inert electron pair effect 2. Know the reactions of ammonia, understand the thermal decomposition trend of ammonium salts 3. Know the properties of nitrous acid and nitrites; understand the structure of nitric acid and nitrate radical; understand the thermal decomposition trend of nitrates 4. Know well the properties of phosphoric acid and phosphates 5. Know the properties of oxides of As, Sb, Bi and their hydrates; understand the properties of sulfides of As, Sb, Bi; know the trends of these compounds 6. Understand the properties of the salts of As, Sb, Bi 7. Understand the identification methods for NH4 + , NO2 - , NO3 - , PO4 3- and Bi3+
Section One The general Properties of Elements of the Nitrogen Group 1. Know the following 1) Valence shell configuration nsn 2) Nonmetal→ metalloid→ metal 3) Oxidation number:0、+3、+5 4) Bonding character 2. Inert electron pair effect: the same group, the stability will increase from up to down when the elements have lower oxidation number; but the stability will decrease from up to down when the elements have higher oxidation number 第3页 2006-02-22
第 3 页 2006-02-22 3 Section One The General Properties of Elements of the Nitrogen Group 1. Know the following: 1) Valence shell configuration ns2 np3 2) Nonmetal → metalloid → metal 3) Oxidation number: 0、+3、+5 4) Bonding character 2. Inert electron pair effect: In the same group, the stability will increase from up to down when the elements have lower oxidation number; but the stability will decrease from up to down when the elements have higher oxidation number
Section Two Nitrogen and Its main Compounds IThe properties of ammonia and ammonium salts 1)Physical properties of ammonia (1)Ammonia is a colorless gas with an exceedingly pungent ordor 2)Readily soluble in the water, one volume H2O can dissolve seven hundred volumes NH3 (15mol.L-) (3)It condenses to a liquid at-33C at ambient pressure(25C/9.9 atm (4) When liquid ammonia becomes gas, it will absorb a great deal of heat, so we can use it as a refrigeration reagent (5)Liquid ammonia is in some ways similar to liquid water. Salts dissolve in ammonia to form conducting solutions, but solubilities are usually lower in ammonia than in water. Alkali metals dissolve in liquid ammonia, and the solution is called liquid ammonia solution 2)Chemical properties of ammonia (1)Addition reaction: H, M", molecules NH3+H→NH4 4NH3+Cu2→[Cu(NH3]2 2NH3+Ag→[Ag(NH3)2] 8NH3+ CaCl2-CaCI2 8NH3 (2)Substitution reaction: One hydrogen atom is replaced: NaNH2; two hydrogen atoms are replaced: Ag2NH; three hydrogen atoms are replaced Li3N (3)Oxidation reaction: O2, MXOy, X2 400 4NH3+ 30 2N2↑+6H2O 800CP 4NH3+5O2 4NO↑+6H2O 2NH3+3Cu0 4 3Cu+N2↑+3H2O 2NH3+3Cl2→N2↑+6HCl 3)The properties of ammonium salts Ions NH4 rb- r/ Dm 143 133 148 95 第4页 2006-02-22
第 4 页 2006-02-22 4 Section Two Nitrogen and Its main Compounds 1.The properties of ammonia and ammonium salts 1) Physical properties of ammonia: (1) Ammonia is a colorless gas with an exceedingly pungent ordor (2) Readily soluble in the water, one volume H2O can dissolve seven hundred volumes NH3 (15mol·L-1) (3) It condenses to a liquid at -33 ℃ at ambient pressure (25℃/9.9 atm) (4) When liquid ammonia becomes gas, it will absorb a great deal of heat, so we can use it as a refrigeration reagent (5) Liquid ammonia is in some ways similar to liquid water. Salts dissolve in ammonia to form conducting solutions, but solubilities are usually lower in ammonia than in water. Alkali metals dissolve in liquid ammonia, and the solution is called liquid ammonia solution 2) Chemical properties of ammonia: (1)Addition reaction: H+ , Mn+, molecules NH3 + H+ → NH4 + 4NH3 + Cu2+ → [Cu(NH3)4] 2+ 2NH3 + Ag+ → [Ag(NH3)2] + 8NH3 + CaCl2 →CaCl2·8NH3 (2) Substitution reaction: One hydrogen atom is replaced: NaNH2; two hydrogen atoms are replaced: Ag2NH; three hydrogen atoms are replaced: Li3N (3) Oxidation reaction: O2, MxOy, X2 4NH3 + 3O2→C0 400 2N2↑ + 6H2O 4NH3 + 5O2 ⎯⎯C ⎯⎯Pt− →Rh 0 800 4NO↑ + 6H2O 2NH3+3CuO →Δ 3Cu +N2↑ +3H2O 2NH3 + 3Cl2 → N2↑ + 6HCl 3) The properties of ammonium salts Ions NH4 + K+ Rb+ Na+ r + /pm 143 133 148 95
a)Ammonium salts of non-oxidative volatile acid NH3↑+ corresponding acid↑ NH3↑+HC↑ NH4HCO NH3↑+CO2↑+H2O b)Ammonium salts of non-oxidative involatile acid NH3ftacid or acid ammonium salt (H4)3PO4 3NH3↑+H3PO4 (NH4)2SO4 NH3↑+NH4HSO4 c) Ammonium salts of oxidative acid N2t+ h2O or N201+ H20 N,O: laughing gas (NH4)2 Cr2O7 N2↑+Cr2O3+4H2O NHANO N2↑+2H2O 210 NHgNO3 N2O↑+2H2O 2NHANO 2N2↑+O2↑+4H2O d) Identification of NH4 3 NHA+OHA> H2O+NH3↑ NH4+Nessler' s reagent red-brown 2.The properties of nitrous acid and nitrites: DHNO2 is a weak acid, Ka=7.2x10 2)The pure acid is unknown, even aqueous solutions of nitrous acid are unstable, decomposing when heated according to the reaction NO2+H→HNO2→N23bue)+H2O NO↑+NO2↑ 3)Most nitrites are soluble in water except AgNO2, and are poisonous and carcinogenic 4)Oxidizing-reducing properties EA: NO: 0.94 HNO2 0.996 NO NO3001NO2-046NO 第5页 2006-02-22
第 5 页 2006-02-22 5 a) Ammonium salts of non-oxidative volatile acid→Δ NH3↑+ corresponding acid↑ NH4Cl→Δ NH3↑ + HCl↑ NH4HCO3→Δ NH3↑ + CO2↑ + H2O b) Ammonium salts of non-oxidative involatile acid→Δ NH3↑+acid or acid ammonium salt (NH4)3PO4→Δ 3NH3↑ + H3PO4 (NH4)2SO4→Δ NH3↑ + NH4HSO4 c) Ammonium salts of oxidative acid →Δ N2↑+ H2O or N2O↑+ H2O N2O: laughing gas (NH4)2Cr2O7 →Δ N2↑ + Cr2O3 + 4H2O NH4NO2 →Δ N2↑+ 2H2O NH4NO3 about ⎯⎯⎯→C 0 210 N2O↑+ 2H2O 2NH4NO3 > ⎯⎯→C 0 300 2N2↑ + O2↑ + 4H2O d) Identification of NH4 + ○ 1 NH4 + + OH- →Δ H2O +NH3↑ ○ 2NH4 + +Nessler’s reagent→Δ red-brown↓ 2.The properties of nitrous acid and nitrites: 1)HNO2 is a weak acid, Ka θ =7.2×10-4 2) The pure acid is unknown, even aqueous solutions of nitrous acid are unstable, decomposing when heated according to the reaction: NO2 - +H+ →HNO2→N2O3(blue)+H2O NO↑+NO2↑ 3) Most nitrites are soluble in water except AgNO2, and are poisonous and carcinogenic 4) Oxidizing-reducing properties EA θ : NO3 - 0.94 HNO2 0.996 NO EB θ : NO3 - 0.01 NO2 - -0.46 NO