1. LecturePLUS Timberlake1 8.2 & 8.3 – Acids, Bases & the pH Scale

2. LecturePLUS Timberlake2 Acids and Bases Acids produce H + in aqueous solutions water HCl H + (aq) + Cl - (aq) Bases produce OH - in aqueous solutions water NaOH Na + (aq) + OH - (aq)

3. LecturePLUS Timberlake3 Acids þ Produce H + ions in water þ Produce a negative ion (-) too þ Taste sour þ Corrode metals þ React with bases to form salts and water þ Are electrolytes þ Turn blue litmus paper red

4. LecturePLUS Timberlake4 Some Common Acids HCl hydrochloric acid HNO 3 nitric acid H 3 PO 4 phosphor ic acid H 2 SO 4 sulfur ic acid CH 3 COOH acet ic acid

5. LecturePLUS Timberlake5 Bases Produce OH - ions in water Taste bitter, chalky Are electrolytes Feel soapy, slippery React with acids to form salts and water Turn red litmus paper blue

6. LecturePLUS Timberlake6 Some Common Bases NaOHsodium hydroxide KOH potassium hydroxide Ba(OH) 2 barium hydroxide Mg(OH) 2 magnesium hydroxide Al(OH) 3 aluminum hydroxide

7. The pH Scale –the pH scale is a scale from 0 to 14 which represents how acidic or basic a solution is –pH stands for “power of hydrogen”; the mathematical expression is pH = - log [H + ] –Acidic solutions have a pH below 7 (0-6.5) –Basic solutions have a pH above 7 (7.5-14) –Neutral solutions have a pH equal to 7 (6.6-7.4) 19.2

8. The pH Concept –pH and Significant Figures 19.2