Buffers-Unit 24

Sodium Acetate

Salt of acetic acid, NaC2H3O2.

Acetic Acid

Weak acid represented as HC2H3O2.

Buffer Solution

Resists pH changes upon acid/base addition.

Conjugate Base

Species formed when an acid donates a proton.

Conjugate Acid

Species formed when a base accepts a proton.

Acidic Buffer

Contains weak acid and its conjugate base.

Basic Buffer

Contains weak base and its conjugate acid.

Henderson-Hasselbalch Equation

pH = pKa + log([A-]/[HA]).

Buffer Capacity

Amount of acid/base a buffer can neutralize.

pKa

Negative logarithm of the acid dissociation constant.

ICE Table

Used to calculate equilibrium concentrations.

Equilibrium Constant (Ka)

Ratio of products to reactants at equilibrium.

Weak Acid

Acid that partially dissociates in solution.

Weak Base

Base that partially dissociates in solution.

Strong Acid

Completely dissociates in solution, no buffer formed.

Strong Base

Completely dissociates in solution, no buffer formed.

pH Calculation

Determines acidity/basicity of a solution.

Buffer Limit

Point where buffer can no longer maintain pH.

Concentration

Amount of solute in a given volume of solution.

Molarity (M)

Moles of solute per liter of solution.

Equilibrium Reaction

Reaction where forward and reverse rates are equal.

pH of Buffer

Depends on concentrations of acid and base.

Salt Method for Buffer

Add weak acid and conjugate base salt.

Buffer System Selection

Choose based on pKa proximity to desired pH.

HCl and HClO

Mixing strong acid with weak acid does not buffer.