patino_chm2046_chapter16

# 010 by 1016 the effect of ph on solubility for

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Unformatted text preview: 1 x 10-18 = [Hg22+] [Cl-]2 Solution [Cl-] that can exist when [Hg22+] = 0.010 M, [Cl-]2 = Ksp / [Hg22+] [Cl− ] = K sp 0.010 = 1.1 x 10-8 M If this conc. of Cl- is just exceeded, Hg2Cl2 begins to precipitate! begins Precipitating an Insoluble Salt Precipitating Hg2Cl2(s) ⇄ Hg22+(aq) + 2 Cl-(aq) (s) Ksp = 1.1 x 10-18 (Now raise [Cl-]) If we continue adding Cl− until [Cl-] = 1.0 M, What is the value of [Hg22+] at this at point? point? Solution [Hg22+] = Ksp / [Cl-]2 [Cl sp = Ksp / (1.0)2 = 1.1 x 10-18 M The concentration of Hg22+ has been reduced (from 0.010) by 1016 ! The Effect of pH on Solubility • for insoluble ionic hydroxides, the higher the pH, the lower the solubility of the ionic hydroxide – low pH, the higher the solubility (H+ reacts with OH-) – higher pH = increased [OH−] = lowering solubility High [OH−] high pH left M(OH)n(s) ⇄ Mn+(aq) + nOH−(aq) High [H+] low pH right • for insoluble ionic compounds that contain anions of weak acids (HA), the lower the pH (higher [H3O+], lower [A−]), the higher the solubility M2(CO3)n(s) ⇄ 2 Mn+(aq) + nCO32−(aq) H3O+(aq) + CO32− (aq)⇄ HCO3− (aq) + H2O(l) high K65 Barium Sulfate Barium Ksp = 1.1 x 10-10 (a) BaSO4 is a common mineral, appearing as a white powder or colorless crystals. (b) BaSO4 is opaque to x-rays. Drinking a BaSO4 cocktail enables a physician to exam the intestines. The Common Ion Effect Calculate the solubility of BaSO4 in (a) pure Calculate water and (b) in 0.010 M Ba(NO3)2. water Ksp for BaSO4 = 1.1 x 10-10 1.1 BaSO4(s) ⇄ Ba2+(aq) + SO42-(aq) (s) Solution Solubility in pure water = [Ba2+] = [SO42-] = x Ksp = [Ba2+] [SO42-] = x2 x = (Ksp)1/2 = 1.1 x 10-5 M Solubility in pure water = 1.1 x 10-5 mol/L The Common Ion Effect Calculate the solubility of BaSO4 in (a) pure water and (b) in 0.010 M Ba(NO3)2. (b) Ksp for BaSO4 = 1.1 x 10-10 1.1 BaSO4(s) ⇄ Ba2+(aq) + SO42-(aq) (s) add some Ba2+ Solution Solution Solubility in pure water = 1.1 x 10-5 mol/L. Now add BaSO4 to water alread...
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## This note was uploaded on 11/07/2011 for the course CHM 2045 taught by Professor Geiger during the Fall '08 term at University of Central Florida.

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