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Unformatted text preview: Chapter 19
Ionic Equilibria in Aqueous Systems Equilibria in Aqueous Systems 19-1 Ionic Equilibria Aqueous Systems Ionic Equilibria in Aqueous Systems 19.1 Equilibria of Acid-Base Buffer Systems 19.2 Acid-Base Titration Curves 19.3 Equilibria of Slightly Soluble Ionic Compounds 19.4 Equilibria Involving Complex Ions 19-2 Acid-base buffer - a solution that lessens the impact on pH from the addition of acid solution that lessens the impact on pH from the addition of acid or base The effect of adding acid or base to an unbuffered solution. The effect of adding acid or base to a buffered solution. effect of adding acid or base to buffered solution. 19-3 How to keep a nearly constant pH?
• A buffer must contain an acid component that can react with the added OH- ion, and a basic component that can react with added H3O+ ion
– Cannot be simple mixture of acid and base—they would neutralize! • Most often, the components of a buffer are the conjugate acid-base often the components of buffer are the conjugate acid pair of a weak acid (or base)
– for example, acetic acid (CH3COOH) and acetate ion (CH3COO-) • • How a buffer works: The common-ion effect If we dissolve acetic acid in a sodium acetate solution: we dissolve acetic acid in sodium solution:
CH3COOH(aq) + H2O(l) CH3COO- is called the common ion : called the common ion CH3COO-(aq) + H3O+(aq) • It is common to both the acetic acid and sodium acetate solutions • It suppresses the dissociation of CH3COOH th di CH 19-4 ...
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This note was uploaded on 07/31/2010 for the course CHEM CHEM 01C taught by Professor Unknown during the Spring '10 term at UC Riverside.
- Spring '10