common-ion-effect-handout

common-ion-effect-handout - Example 14.17 (pg. 581) The...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
The common ion effect, predicting precipitation : Read pg. 580 – 582 (common ion effect section only). Do PE 20 - 21 PbI 2 (s) Pb 2+ (aq) I (aq) 12 00 . 1 0 x2 x 0.10 + 2x x R I C E Ksp = [x] [0.10 + 2x] 2 = 7.9 x 10 9 Ksp = [Pb 2+ (aq)] [I (aq)] 2 Example 14.17 (pg. 581) Molar solubility of PbI 2 ? Ksp = 7.9 x 10 –9 Concentration of NaI is 0.10, thus [I ] = 0.10 NaI(s) Na + (aq) + I (aq) x is small, thus we can ignore 2x in 0.10 + 2x Ksp = [x] [0.10] 2 = 7.9 x 10 9 , x = 7.9 x 10 –7 M Predicting when precipitation occurs Read pg. 582. Do PE 22, 23 Similar to Kc vs. mass action expression to predict if equilibrium exists (and which way it will shift) E.g. in example 14.18 PbCl 2 (s) Pb 2+ (aq) + 2Cl (aq) (NaCl and Pb(NO 3 ) are soluble according to the solubility rules; they will not precipitate) Ksp = 1.7 x 10 -5 , [Pb 2+ ][Cl ] 2 = 3.4 x 10 –5 Ion product is large … to reduce, equilibrium must shift left … precipitate forms Predicting when precipitation occurs
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/12/2011 for the course CHEM 1010 taught by Professor Marshall during the Spring '11 term at North Texas.

Ask a homework question - tutors are online