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Catalyst. It is found that 1.1 x 10 -2 g of SrF 2 dissolves per 100 mL of solution. Calculate the solubility product of SrF 2. End. Acetate. Lecture 8.2 – Application of K sp. Today’s Learning Targets.
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Catalyst • It is found that 1.1 x 10-2g of SrF2 dissolves per 100 mL of solution. Calculate the solubility product of SrF2. End
Today’s Learning Targets • LT 8.4 – I can hypothesize about which slightly soluble compound will precipirate first through utilization of the Ksp
Predicting Precipitation • Recall, the reaction quotient (Q) can be used to determine the direction an equilibrium needs to shift in order to achieve equilibrium: Q > Ksp: Shift left and precipitate more Q < Ksp: Shift right and dissolve more Q = Ksp: Solution is at equilibrium • Therefore, we can predict whether more or less solid will precipitate based on this answer
Class Example • Does a precipitate form when 0.10 L of 8.0 x 10-3 M Pb(NO3)2 is added to 0.40 L of 5.0 x 10-3 M Na2SO4? Note – the Ksp of PbSO4 is 6.3 x 10-7
Table Talk • Doe a precipitate form when 0.050 L of 2.0 x 10-2 M NaF is mixed with 0.010 L of 1.0 x 10-2 M Ca(NO3)2. KSP (CaF2) = 3.9 x 10^-11
Selective Precipitation • Oftentimes, we have solutions that contain multiple solubility equilibriums. • We can selectively precipirate some of the compounds, but not all, by utilizing Ksp • The smaller the Ksp of an ion, the more likely it will precipitate from solution first.
Class Example • A solution contains 1.0 x 10-2 M Ag+ and 2.0 x 10-2 M Pb2+. When Cl- is added, both AgCl (Ksp = 1.8 x 10-10) and PbCl2 (Ksp = 1.7 x 10-5) can pre. What concentration of Cl- is necessary to begin precipitation of each salt? Which salt precipitates first?
Table Talk • A solutions consists of 0.050 M Mg2+ and Cu2+. Which ion precipitates first when OH- is added? What concentration of [OH-] is needed to begin to precipitation of each cation? NOTE – Ksp of Mg(OH)2 is 1.8 x 10-11 and Ksp of Cu(OH)2 is 4.8 x 10-20.
Drill Baby Drill • Drill – Calculating Molar Solubilities • Drill – Predicting Precipitation • Integrated Practice – Connecting Ksp to past Units
Closing Time • Read 17.1, 17.4, 17.5, 17.6, and 17.7 • Homework: Drills and Integrated Practice • Exam Debrief – Thursday or Friday 3:30 – 4