1Week 11 CHEM 1310 - Sections L and M 1Ch 8 - Applications of Equilibrium 8.1 Solutions of Acids or Bases Containing a Common Ion 8.2 Buffered Solutions 8.4 Buffer Capacity 8.5 Titrations and pH Curves 8.6 Acid-Base Indicators 8.8 Solubility Product Sections to Skip: 8.3, 8.7, 8.9, and 8.10Week 11 CHEM 1310 - Sections L and M 2Equivalence Point Equivalence point is determined by thestoichiometry not by the pHWeek 11 CHEM 1310 - Sections L and M 3Equivalence Point The weaker the acid, the greater the pH at whichthe equivalence point occurs.Notice how the vol of NaOHadded does not change for several weak acids2Week 11 CHEM 1310 - Sections L and M 4Solubility Product Constant The solubility product constant, Ksp, dictatesthe amount of solid that will dissolve Excess solid salt Saturated solution of aqueous ionsAB (s) ↔ xA+ (aq) + yB- (aq)Ksp = [A+]x [B-]y[A+][B-][AB]Ksp =[AB] becomes “1” for pure solidsWeek 11 CHEM 1310 - Sections L and M 5Ksp Values for Common Ionic SolidsWeek 11 CHEM 1310 - Sections L and M 6Ksp and StoichiometryAg2SO4(s) 2Ag+(a q) + SO42-(aq)= [Ag+]2[SO42-] = Ksp[Ag+]2 [SO42-][Ag2SO4]Ksp =excessFe(OH)3(s) Fe+3(aq) + 3OH-1(aq)Ksp =[Fe+3]1[OH1-]3[Fe(OH)3]= [Fe+3][OH1-]3 = Kspexcess3Week 11 CHEM 1310 - Sections L and M 7Solubility Solubility is the extent to which a solute candissolve into a solution Molar Solubility, s, is the concentration atwhich dissolution-precipitation occurs for agiven ionic saltKsp = [Ag+]2[SO42-]Ag2SO4(s) 2Ag+(a q) + SO42-(aq)s = [Ag2SO4]How can the Ksp be used to determinethe solubility of a given solute?Week 11 CHEM 1310 - Sections L and M 8Solubility Calculations The solubility expression for the dissolutionof Ag2SO4 in water is:Ksp = [Ag+]2[SO42-]Ag2SO4(s) 2Ag+(aq) + SO42-(aq)s 2s sKsp = (2s)2 x s = 4s3 = 1.2 x 10-5s =1.2 x 10-543 s = 0.014MWeek 11 CHEM 1310 - Sections L and M 9Example Problem Determine the mass of lead(II) iodatedissolved in 2.50 L of a saturated aqueoussolution of Pb(IO3)2 at 25°C. Ksp of Pb(IO3)2 = 2.6 x 10-13Solve on board4Week 11 CHEM 1310 - Sections L and M 10Example Problem Determine the Ksp of silver sulfate at 25 °C ifits mass solubility is 8.3 g/L. Solution Chemical Formula for silver sulfate Dissolution equilibrium equation Define Ksp equation Convert mass solubility to molar solubility Compute KspWeek 11 CHEM 1310 - Sections L and M 11PRS Question In the chemical equation describing thedissolution of Mg(OH)2(s) in water, thestoichiometry coefficient for the hydroxideion is:1. -22. -13. 04. +15. +2Week 11 CHEM 1310 - Sections L and M 12PRS Question In the chemical equation describing thedissolution of Mg(OH)2(s) in water, thestoichiometry coefficient for the hydroxideion is:1. -22. -13. 04. +15. +2Mg(OH)2(s) Mg +2 + 2 OH-15Week 11 CHEM 1310 - Sections L and M 13PRS Question What is the Ksp expression for thedissolution of Mg(OH)2 in water?1. [Mg2+] x [OH-]2. [Mg2+] x [OH-]23. [Mg2+] x 2[OH-]4. [Mg2+] x (2[OH-])2Week 11 CHEM 1310 - Sections L and M 14PRS Question What is the Ksp expression for thedissolution of Mg(OH)2 in water?1. [Mg2+] x [OH-]2. [Mg2+] x [OH-]23. [Mg2+] x 2[OH-]4. [Mg2+] x (2[OH-])2Mg(OH)2(s) Mg2+ + 2 OH-Ksp = [Mg2+] x [OH-]2Assume heterogeneousequilibriumWeek 11 CHEM 1310 - Sections L and M 15PRS Question What is the solubility expression for the dissolutionof Mg(OH)2 where “s” = [Mg(OH)2]?1. s22. 2s23. 4s34. 2s35. s36Week 11 CHEM 1310 - Sections L and M 16PRS Question What is the solubility expression for the dissolutionof Mg(OH)2 where “s” = [Mg(OH)2]?1. s22. 2s23. 4s34. 2s35. s3Mg(OH)2(s) Mg2+ + 2 OH-s s
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