1Week 11 CHEM 1310 - Sections L and M 1Ch 8 - Applications of Equilibrium 8.8 Solubility Product More Examples Relative Solubility Effect of pH on Solubility Effect of Common Ion on Solubility Sections to Skip: 8.3, 8.7, 8.9, and 8.10Week 11 CHEM 1310 - Sections L and M 2More Examples of Ksp What is the molar solubility of AgCl(s)?AgCl(s) Ag+(aq) + Cl-(aq) Ksp = [Ag+] x [Cl-] = 1.6 x 10-10Solve on boardNotice format of this equilibrium:AB A+ + B-Week 11 CHEM 1310 - Sections L and M 3More Analysis of KspWhat is the Ksp when the salt has a differentstoichiometric format?Salt Format Ksp ExpressionAB [A+] x [B-] = s2AB2[A+] x [B-]2 = s x (2s)2 = 4s3A2B2Week 11 CHEM 1310 - Sections L and M 4More Examples of KspX3Y2(s) 3X2+(aq) + 2Y3-(aq) Ca3(PO4)2(s) 3Ca2+(aq) + 2PO43-(aq) [Ca2+] = 3 [Ca3(PO4)2] = 3s[PO43-] = 2 [Ca3(PO4)2] = 2s Ksp = 1.3 x 10-32 = [Ca2+]3 x [PO43-]2Ksp = 1.3 x 10-32 = (3s)3 x (2s)2 = 27s3 x 4s2 = 108s5Week 11 CHEM 1310 - Sections L and M 5Solubility What is the solubility of Ca3(PO4)2?Ca3(PO4)2(s) 3Ca2+(aq) + 2PO43-(aq) Ksp = 1.3 x 10-32 = (3s)3 x (2s)2 = 27s3 x 4s2 = 108s5s = 1.3 x 10-32 1085s = 1.6 x 10-7 MWeek 11 CHEM 1310 - Sections L and M 6More Analysis of KspSalt Format Ksp ExpressionAB [A+] x [B-] = s2AB2[A+] x [B-]2 = s x (2s)2 = 4s3A2BA3B2108s53Week 11 CHEM 1310 - Sections L and M 7Relative SolubillitySalt KspSolubility, MAgI 1.5 x 10-161.2 x 10-8CuI 5.0 x 10-122.2 x 10-6CaSO46.1 x 10-57.8 x 10-3As Ksp increases, solubility also increasesNotice how all salts being compared here have this format:AB A+ + B- Solve for solubility when comparing salts with different formatsWeek 11 CHEM 1310 - Sections L and M 8Effect of pH on Solubility Many solids dissolve more readily in acidicsolutions than in water.Zn(OH)2(s) Zn2+(aq) + 2 OH-(aq)[Zn2+][OH-]2 = Ksp = 4.5 × 10-17As pH decreases (i.e. as soln is made more acidic): [H+] increases[OH-] decreasesEquilibrium shifts to RIGHTMore Zn(OH)2 dissolvesWeek 11 CHEM 1310 - Sections L and M 9Effect of pH on Solubility Estimate the molar solubility of Fe(OH)3 inwater. Estimate the molar solubility of Fe(OH)3 in asolution that is buffered to a pH of 2.9. Ksp = 1.1 x 10-36Fe(OH)3(s) Fe3+(aq) + 3 OH-(aq)y y 3ySolve on board4Week 11 CHEM 1310 - Sections L and M 10Common Ion on Solubility If a solution and a solid salt to be dissolvedin it have an ion in common, then thesolubility of the salt is depressed.AB (s) ↔ A+ (aq) + B- (aq)What happens if some extra A+ or B- is addedfrom another source?Week 11 CHEM 1310 - Sections L and M 11Common Ion on Solubility The Ksp of thallium(I) iodate (TlIO3) is 3.1 x10-6 at 25°C. Determine the molar solubilityof TlIO3 in 0.050 M KIO3 at 25°C.TlIO3(s) ↔ Tl+(aq) + IO3-(aq)[s] [s][s] [Tl+] (mol L-1) [IO3-] (mol L-1)Initial concentration 0 mol L-1 0.050 mol L-1 Equilibrium concentration s 0.050 + sChange in concentration +s +sWeek 11 CHEM 1310 - Sections L and M 12PRS Question Which salt MCO3 or M2CO3 is more solublein water? “M” denotes a metal.1. MCO3 Ksp = 4.0 x 10 -102. M2CO3 Ksp = 3.2 x 10 -11Solve on board5Week 11 CHEM 1310 - Sections L and M 13PRS Question For Mg(OH)2(s), (Ksp = 1.2 x 10-11), as thepH is raised, the solubility of Mg(OH)2 inwater should:1. Decrease2. Increase3. Remain the sameMg(OH)2(s) Mg2+(aq) + 2 OH-(a q)[Mg2+][OH-]2 = Ksp = 1.2 × 10-11HINTWeek 11 CHEM 1310 - Sections L and M 14PRS Question For Mg(OH)2(s), (Ksp = 1.2 x 10-11), as thepH is raised, the solubility of Mg(OH)2 inwater should:1. Decrease2. Increase3. Remain the sameMg(OH)2(s) Mg2+(aq) + 2 OH-(a q)[Mg2+][OH-]2 = Ksp = 1.2 ×
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