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SOLUBILITY I. Saturated Solution BaSO 4(s)  Ba 2+ (aq) + SO 4 2- (aq)

SOLUBILITY I. Saturated Solution BaSO 4(s)  Ba 2+ (aq) + SO 4 2- (aq) Equilibrium expresses the degree of solubility of solid in water. Ksp = solubility product constant Ksp = [Ba 2+ ] [SO 4 2- ] = 1.1 x 10 -10 Represents the amount of dissolution, the smaller the Ksp value,

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SOLUBILITY I. Saturated Solution BaSO 4(s)  Ba 2+ (aq) + SO 4 2- (aq)

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  1. SOLUBILITY I. Saturated Solution BaSO4(s) Ba2+(aq) + SO42-(aq) Equilibrium expresses the degree of solubility of solid in water. Ksp = solubility product constant Ksp = [Ba2+] [SO42-] = 1.1 x 10-10 Represents the amount of dissolution, the smaller the Ksp value, the less amount of solid dissolved. Q1. Write the solubility product expression for Hg2Cl2 & HgCl2 Q2. Exactly 0.133 mg of kgBr will dissolve in 1.00 L of water. What is the value of Ksp for AgBr?

  2. Interconverting solubility and Ksp SOLUBILITY OF COMPOUND (g/L) MOLAR SOLUBILITY OF COMPOUND (mol/L) MOLAR CONCENTRATION OF IONS Ksp

  3. II. Solubility vs Solubility Product Solubility: The quantity of solute that dissolves to form a saturated solution. (g/L) Molar Solubility: (n solute/L saturated solution) Ksp: The equilibrium between the ionic solid and the saturated solution. Q1. A student finds that the solubility of BaF2 is 1.1 g in l.00 L of water. What is the value of Ksp? Q2. Calomel (Hg2Cl2) was once used in medicine. It has a Ksp = 1.3 x 10-18. What is the solubility of Hg2Cl2 in g/L?

  4. III. Solubility and Common Ion effect CaF2(s) Ca2+(aq) + 2F-(aq) The addition of Ca2+ or F- shifts the equilibrium. According to Le Chatelier’s Principle, more solid will form thus reducing the solubility of the solid. Solubility of a salt decreases when the solute of a common ion is added. Q1. What is the molar solubility of silver chloride in 1.0 L of solution that contains 2.0 x 10-2 mol of HCl?

  5. IV. CRITERIA FOR PRECIPITATION OF DISSOLUTION BaSO4(s) Ba2+(aq) + SO42-(aq) Equilibrium can be established from either direction. Q1. (Ion Product) is used to determine whether or not precipitation will occur. Q < K  solid dissolves Q = K equilibrium (saturated solution) Q > K  ppt Q2. Calcium phosphate has a Ksp of 1.0 x 10-26, if a sample contains 1.0 x 10-3 M Ca2+ and 1.0 x 10-8 M PO43- Ions, calculate Q and predict whether Ca3(PO4)2 will precipitate?

  6. Q3. Exactly 0.400 L of 0.50 M Pb2+ and 1.60 L of 2.5 x 10-8M Cl- are mixed together to form 2.00L. Calculate Q and predict if a ppt will occur. Ksp = 1.6 x 10-5

  7. 1. When 50.0 mL of 0.100 M AgNO3 and 30 mL of 0.060 M Na2CrO4 are mixed, a precipitate of silver chromate is formed. The solubility product is 1.9 x 10-12. Calculate the [Ag+] and [CrO42-] remaining in solution at equilibrium. 2. Suppose 300 mL of 8 x 10-6 M solution of KCl is added to 800 mL of 0.004 M solution of AgNO3. Calculate [Ag+] and [Cl-] remaining in solution at equilibrium.

  8. COMPLEX ION EQUILIBRIA Transition metal Ions form coordinate covalent bonds with molecules or anions having a lone pair of e-. AgCl(s) Ag+ + Cl- Ksp 1.82 x 10-10 Ag+ + 2NH3  Ag(NH3)2+ Kf 1.7 x 107 AgCl + 2NH3  Ag(NH3)2+ + Cl- Complex Ion H3N:AG:NH3 metal = Lewis is acid ligand = Lewis base Kf = [Ag(NH3)2+] formation constant [Ag+][NH3]2

  9. Kf = Formation Constant M+ + L- ML Kd = Dissociation constant ML  M+ + L- Kd = 1 Kf

  10. Q 1. Calculate [Ag+] present in a solution at equilibrium when concentrated NH3 is added to a 0.010 M solution of AgNO3 to give an equilibrium concentration of [NH3] = 0.20M. Q2. Silver chloride usually does not ppt in solution of 1.0 M NH3. However AgBr has a smaller Ksp. Will AgBr ppt form a solution containing 0.010 M AgNO3, 0.010 M NaBr and 1.0 M NH3? Ksp = 5.0 x 10-13 Q3. Calculate the molar solubility of AgBr in 1.0M NH3?

  11. EFFECT OF pH ON SOLUBILITY CaF2 Ca2+ + 2F- 2F- + 2H+  2HF CaF2 + 2H+ Ca2+ + 2HF Salts of weak acids are more soluble in acidic solutions. Salts with anions of strong acids are largely unaffected by pH. Q1. Consider the two slightly soluble salts BaF2 and AgBr. Which of these two would have its solubility more affected by the addition of a strong acid? Would the solubility of that salt increase or decrease.

  12. 3 STEPS TO DETERMINING THE ION CONCENTRATION AT EQUILIBRIUM I. Calculate the [Ion]i that occurs after dilution but before the reaction starts. II. Calculate the [Ion] when the maximum amount of solid is formed. - we will determine the limiting reagent and assume all of that ion is used up to make the solid. - The [ ] of the other ion will be the stoicometric equivalent. III. Calculate the [Ion] at equilibrium. Since we assume the reaction went to completion but by definition a slightly soluble can’t. We must account for some of that solid re-dissolving back into solution.

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