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