中国海洋大学：《无机化学 Concise Inorganic Chemistry》课程教学资源（PPT课件，英文）Chapter 5 Equilibria of Slightly Soluble Ionic Compounds

Glossaryioniccompoundsn.离子型化合物a.可溶的solubleelectrolyte电解质insolublea.不溶的precipitaten.沉淀n.溶解度solubilityhomogeneousa.均相的，均匀的n.溶质soluteheterogeneousa.异相的，不均匀的dissolublea.可溶解的heterogeneousequilibria 异相平衡dissolutionn.溶解theSolubility-ProductConstant溶度积常数dissociatev.离解reactionquotient反应商dissociationn.离解作用

1 Glossary soluble a. 可溶的 insoluble a.不溶的 solubility n.溶解度 solute n.溶质 dissoluble a.可溶解的 dissolution n.溶解 dissociate v.离解 dissociation n.离解作用 ionic compounds n. 离子型化合物 electrolyte 电解质 precipitate n.沉淀 homogeneous a.均相的，均匀的 heterogeneous a.异相的，不均匀的 heterogeneous equilibria 异相平衡 the Solubility-Product Constant 溶度积常数 reaction quotient 反应商

PbCl LeadchloridegramAgCI SilverchlorideliterAgBr SilverbromideAg,CrO,SilverchromatemoleAg,SSilversulfidemolarAgNO, silver nitratemolar solubilityCaSO,CalciumsulfateBaSO Barium sulfateHCI hydrochloric acidH,SO, sulphuric acidHNO, Nitric acid

2 PbCl2 Lead chloride AgCl Silver chloride AgBr Silver bromide Ag2CrO4 Silver chromate Ag2S Silver sulfide AgNO3 silver nitrate CaSO4 Calcium sulfate BaSO4 Barium sulfate HCl hydrochloric acid H2SO4 sulphuric acid HNO3 Nitric acid gram liter mole molar molar solubility

Chapter 5 Equilibria of SlightlySoluble Ionic CompoundsAims to solve two issues:The characteristics of the eguilibriumThe shift of theequilibrium

3 Chapter 5 Equilibria of Slightly Soluble Ionic Compounds Aims to solve two issues: The characteristics of the equilibrium The shift of the equilibrium

140ml5小120AgNO3(aq) + NaCl(aq) = AgCl(s) + NaNO3 (aq)

4 AgNO3 (aq) + NaCl(aq) = AgCl(s) + NaNO3 (aq)

Slightly SolubleThere is no standard rule forthe solubilityvalueInsoluble means S 1g/100gH,0IonicCompoundsare strong electrolytes which dissociatecompletelyin aqueous solution?

5 Slightly Soluble There is no standard rule for the solubility value. Insoluble means S 1g /100gH2O Ionic Compounds are strong electrolytes which dissociate completely in aqueous solution

1 The Characteristics of Equilibria of SlightlySolubleIonicCompounds1-1.The Characteristics : heterogeneous equilibriaBaSO4 (s) 台 Ba2+ (aq)+ SO.2- (aq)Making the assumption of complete dissociationwe can state that for slightly soluble ionic compoundsequilibrium exists between solid solute and dissolved ions

6 1 The Characteristics of Equilibria of Slightly Soluble Ionic Compounds 1-1. The Characteristics ： heterogeneous equilibria BaSO4 (s)  Ba2+ (aq)+ SO4 2- (aq) Making the assumption of complete dissociation, we can state that for slightly soluble ionic compounds, equilibrium exists between solid solute and dissolved ions

1-2. The Solubility-Product Constant---K.p(溶度积常数IEBaSO4 (s) 台 Ba2+ (aq)+ SO.2- (aq)SSKsp=[Ba2+[ SO,2]= S2Generally A.B,mAn+ + nBm-nsmsKs=[A"+]"[B"-]"=[mS]"[nS]=mmn"Sm+n

7 1-2. The Solubility-Product Constant - Ksp(溶度积常数) BaSO4 (s)  Ba2+ (aq)+ SO4 2- (aq) t e S S Ksp = [Ba2+ ][ SO4 2- ] = S 2 Generally AmBn  mAn+ + nBm￾t e mS nS Ksp = [An+] m[ Bm- ] n = [mS] m[nS ] n = mm n n S m+n

1-3. Comparison of K.n and S (molar solubility)Tablel.K.nand S of someIonic CompoundsKpCompositionMolecularS(mol/L)patternFormula1.8 × 10-10AB1.3 × 10-5AgCl5.0 × 10-137.1 × 10-7ABAgBr2.0 × 10-127.9 × 10-5A,BAg,CrO46.7 × 10-502.6 × 10-17A,BAg,SFor molecules with the same pattern, the higher its Ksp,the higher its SFor molecules with different patterns, higher Ksn doesn't mean higher S

8 1-3. Comparison of Ksp and S (molar solubility) Table1. Ksp and S of some Ionic Compounds Composition pattern Molecular Formula Ksp S(mol/L) AB AgCl 1.8  10-10 1.3  10-5 AB AgBr 5.0  10-13 7.1  10-7 A2B Ag2CrO4 2.0  10-12 7.9  10-5 A2B Ag2 S 6.7  10-50 2.6  10-17 For molecules with the same pattern, the higher its Ksp, the higher its S. For molecules with different patterns, higher Ksp doesn’t mean higher S

-The solubility-product Ksn and the molar solubility S.both express the soluble ability of a compound.As formolecules with the same pattern, the higher its Ksp, thehigher its S.But for molecules with different patternshigherK.n doesn't mean higher S.-Another point is that the Ksn is a function of thetemperature, it has nothing to do with ionsconcentrations, while S changes with the ionsconcentrations

9 ▪The solubility-product Ksp and the molar solubility S, both express the soluble ability of a compound. As for molecules with the same pattern, the higher its Ksp, the higher its S. But for molecules with different patterns, higher Ksp doesn’t mean higher S. ▪Another point is that the Ksp is a function of the temperature, it has nothing to do with ions’ concentrations, while S changes with the ions’ concentrations

Example 1: Calculate solubility of AgCI. K., =1.8 × 10-10(a) In 1L water.(b) In 0.01M HCI(c)In 0.01M KNO)Solution:(a)AgCI (s) 台Ag+ + CISSteKsp = S2spS = Ksn =1.3 ×10-5 M10

10 Example 1: Calculate solubility of AgCl. Ksp =1.8  10-10 (a) In 1L water. (b) In 0.01M HCl (c)In 0.01M KNO3 . Solution: (a) AgCl (s)  Ag+ + Cl￾t e S S Ksp = S 2 S =  Ksp =1.3  10-5 M