In the Laboratory Seidman & Moore pp. 380-383 Problems 1-5 page 400

pH In the Laboratory Seidman & Moore pp. 380-383 Problems 1-5 page 400

Ionization of Water

Equllibrium Constant, Keq

Ion Product of Water, KW

Acidity

Measuring pH • Indicater Dyes; Methyl Red, Phenol Red, etc. • pH Paper (Litmus Paper) • pH Meter

pH Meter • Voltmeter with electrode • Measures electrical potential difference across electrode due to protons • 1 pH unit = 60 mV • pH also dependent on temperature

pH Electrode • Filled with reference solution (4 M KCl, sat. AgCl) • Glass semi permable (protons cannot cross) • Glass protected by plastic sleeve • Some are sensitive to Tris buffer

pH Standards • Color coded 4, 7, and 10 • Potassium Hydrogen Pthalate • Standardize everyday • Bracket pH range

pH of Strong Acids • HCl <-> H+ +Cl- • Assume complete dissociation • 1 M HCl, pH = -log [H+] = -log 1 = ? • 0.5 M HCl, pH = -log 0.5 = ? • 6 M HCl, pH = -log 6 = ?

pH of Strong Bases • NaOH <-> Na+ + OH- • Assume complete dissociation • pKW = pH + pOH = 14 • pH = 14 – (-log [OH-]) • 1 M NaOH, pH = 14 – (-log 1) = ? • 0.01 M NaOH, pH = 14 – (-log 0.01) = ? • 6 M NaOH, pH = 14 – (-log 6) = ?

pH of a Weak Acid

In the Laboratory Seidman & Moore pp. 380-383 Problems 1-5 page 400