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Chapter 8. Acids, Bases, and pH. The pH scale. pH scale is labeled 0-14 7 = neutral 0-7 = acids, 7-14 = bases “weak”, closer to 7 “strong”, closer to 0 or 14. Acids (0-7). A compound that produces hydronium (H 3 0 + ) ions when dissolved in H 2 0 Example: HCl + H 2 0 H 3 0 + + Cl -
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Chapter 8 Acids, Bases, and pH
The pH scale • pH scale is labeled 0-14 • 7 = neutral • 0-7 = acids, 7-14 = bases • “weak”, closer to 7 • “strong”, closer to 0 or 14
Acids (0-7) • A compound that produces hydronium (H30+) ions when dissolved in H20 • Example: HCl + H20 H30+ + Cl- • Sour taste, react with metals, produce color changes in indicators • Examples: fruit, shampoo, vinegar
Bases (7-14) • A compound that produces hydroxide ions (OH-) when dissolved in H20 • Example: NaOH + H2O Na+ + OH- • Bitter taste, slippery feel, produces color changes in indicators. • Example: deodorant, Tums (antacid), soap
Neutralization • The rxn of acid + base • Example: H+ + OH- H20 • Neutral substances will not produce color changes in indicators.
Neutralization and Salts • The negative ions of an acid combine with the positive ions of a base to produce an ionic compound called a salt. • The neutralization reaction between acid and base produces a salt and water. • (H3O+ + Cl-) + (Na+ + OH-) 2HOH + (Na+ + Cl-) acid base water salt
Indicators • Something that indicates the pH of a solution or substance • Examples: • Natural (some flowers, cabbage juice, red onion juice) • pH paper (Litmus blue or red, universal)