Principles of Chemistry II © Vanden BoutSolubilityOur start in adventures in Aqueous EquilibriaPrinciples of Chemistry II © Vanden BoutSea Shells are essentially Calcium Carbonate crystals held together by proteinsGiven this information what do you think equilibrium constant will be for this reaction?! A.! ! a number much much less than 1! B.! ! a number approximately equal to 1 ! C.! ! a number much much larger than 1CaCO3 (s) Ca2+(aq) + CO32-(aq)Principles of Chemistry II © Vanden BoutWe will be mostly dividing substances upStrong ElectrolyteWeak ElectrolytePrinciples of Chemistry II © Vanden BoutRock DemoPrinciples of Chemistry II © Vanden BoutRock Demo[Ca2+] = [Ca2+] =How much of the rock dissolved?Principles of Chemistry II © Vanden BoutHow much is very small?Solubility EquilibriaCaCO3 (s) Ca2+(aq) + CO32-(aq)Ksp =Principles of Chemistry II © Vanden BoutSolubility is given in practical unitsMolar SolubilityMoles of solute that will dissolve in 1 L of sovlent (water)Principles of Chemistry II © Vanden BoutSolubility is given in practical unitsMolar SolubilityMoles of solute that will dissolve in 1 L of sovlent (water)Solubilitygrams of solute that will dissolve in 1 L of sovlent (water)Principles of Chemistry II © Vanden BoutWhat is the solubility of AgCl?AgCl (s) Ag+(aq) + Cl-(aq)Ksp = [Ag+][Cl-] = 1.8 x 10-10ReactionInitialChangeEquilibriumAgCl (s) Ag+(aq) + Cl-(aq)Principles of Chemistry II © Vanden BoutWhat is the solubility of AgCl?Ksp = [Ag+][Cl-] = 6 x 10-9ReactionInitialChangeEquilibriumAgCl (s) Ag+(aq) + Cl-(aq)0 0+x +x+x +xKsp = [Ag+][Cl-] =Principles of Chemistry II © Vanden BoutWhat is the solubility of AgCl?Ksp = [Ag+][Cl-] = 1.8x 10-10AgCl (s) Ag+(aq) + Cl-(aq)[Ag+]= 1.3 x 10-5 M M.W. of AgCl is 143.3 g mol-1Principles of Chemistry II © Vanden Bout! A.! ! AgCl Ksp = 1.8 x 10-10! B.! ! FeS Ksp = 8 x 10-19!C.!!LiF Ksp = 1.8 x 10-3 D. ZnSe Ksp = 2 x 10-25Which of the following compounds has the lowest molar solubility?Principles of Chemistry II © Vanden Bout! A.! ! AgCl Ksp = 1.8 x 10-10! B.! ! Cd3(PO4)2 Ksp = 2.5 x 10-30! C.! ! Zn(OH)2 Ksp = 3 x 10-17 D. ZnSe Ksp = 2 x 10-25Which of the following compounds has the lowest molar solubility?Principles of Chemistry II © Vanden BoutWhat is the concentration of Sr2+ in a saturated solution of SrF2? Ksp = [Sr2+][F-] = 4.3 x 10-9ReactionInitialChangeEquilibriumSrF2 (s) Sr2+(aq) + 2F-(aq)1 x 10-3Principles of Chemistry II © Vanden Bout! A.! ! AgCl Ksp = 1.8 x 10-10! B.! ! Cd3(PO4)2 Ksp = 2.5 x 10-30! C.! ! Zn(OH)2 Ksp = 3 x 10-17 D. ZnSe Ksp = 2 x 10-25Decent estimate of the molar solubilitycount the ionstake that “root” of the KspPrinciples of Chemistry II © Vanden BoutGiven that Ksp for AgCl is 1.8 x 10-10,and the NaCl is strong electrolyteWhat do you predict for solubility of AgCl in a 1 M NaCl solution?! A.! ! more soluble than in pure water! B.! ! same solubility as pure water! C.! ! lower solubility than pure waterKsp=Principles of Chemistry II © Vanden BoutGiven that Ksp for AgCl is 1.8 x 10-10,and the NaCl is strong electrolyteWhat is the concentration of Ag+ in a 1 M NaCl solutionthat contains solid AgCl?! A.! ! 1.8 x 10-10 M! B.! ! 1.8 x 10-6 M! C.! ! 1.3 x 10-5 M!! D.! ! 1 M Ksp=Principles of Chemistry II © Vanden BoutWhat is the solubility of AgCl?Ksp = [Ag+][Cl-] = 6 x 10-9ReactionInitialChangeEquilibriumAgCl (s) Ag+(aq) + Cl-(aq)0 1+x +x+x 1+xKsp = [Ag+][Cl-] =Principles of Chemistry II © Vanden BoutSilver Nitrate (AgNO3) and Sodium Chloride (NaCl) are both soluble salts. What will happen if I mix 200 mL of 1 M AgNO3 solution with 100 ml of 1 M NaCl solution given that Ksp for AgCl is 1.8 x 10-10! A.! ! I'll have a solution with Ag+, Cl-, Na+, and NO3- ions ! B.! ! some solid AgCl will form ! C.! ! both B & C !Principles of Chemistry II © Vanden BoutA few useful definitions and ideasPrecipitationInsoluble solid that forms and drops out of solutionWhat is soluble?Many solubility rulesTypically Ksp is given for insoluble compoundsAll Na+, K+, and NO3- salts are solubleSpectator IonsIons that don’t participate in the chemistryPrinciples of Chemistry II © Vanden BoutIonic EquationsNaCl(aq) + AgNO3 (aq)Net ionic equationPrinciples of Chemistry II © Vanden BoutPrecipitation CalculationsFirst take the reaction to completionthen calculate back to the equilibriumKsp is generally small.First assume as much solid as possible formsThen look at what "re-dissolves" into solutionPrinciples of Chemistry II © Vanden BoutIf I mix a 100 mL of 1 M NaCl solutionwith a 200 mL of 1 M AgNO3 solutionhow much solid AgCl will form (Ksp= 1.8 x 10-10)?NaCl(aq) + AgNO3 (aq) AgCl(s) + NaNO3 (aq)Ag+(aq) + Cl-(aq) AgCl(s)Need to convert from concentration to moles!Assume all the maximum amount of AgCl formsPrinciples of Chemistry II © Vanden BoutKsp = [Ag+][Cl-] = 1.8 x 10-10ReactionInitialChangeEquilibriumAgCl (s)
View Full Document
Unlocking...