Group and Discussion Activities

Key Questions
Counterintuitive Examples and Discrepant Events
Metaphors and Analogies
Pictures in the Mind

Key Questions

  1. What are common observable properties of acids and bases? [Acids taste sour, cause blue litmus to turn red, liberate hydrogen gas when they react with certain metals, and neutralize bases. Bases taste bitter, feel slippery, cause red litmus to turn blue, and neutralize acids.]

  2. Identify acids and bases you have encountered in and around your home. [Baking soda (sodium bicarbonate, NaHCO3, base), drain cleaner (sodium hydroxide, NaOH, base), vinegar (acetic acid, HC2H3O2, acid), citrus fruits (citric acid, acid), battery acid (sulfuric acid, H2SO4, acid), antacids (e.g., Milk of Magnesia, Mg(OH)2, base), household ammonia (aqueous ammonia, NH3, base)].

  3. How does the concentration of hydrogen ion vary as pH changes? [As the pH increases, the concentration of H+ decreases.]

  4. From what acid and base could we synthesize sodium nitrate, NaNO3? [The anion of the salt comes from the base and the cation comes from the acid. For NaNO3, the sodium ion, Na+, is supplied by sodium hydroxide, NaOH, and the nitrate ion, NO3-, is supplied by nitric acid, HNO3.]

  5. What are some problems associated with "acid rain"? [Acid rain is a dilute solution of sulfuric acid and nitric acid. Because acids are corrosive, acid rain can cause damage to humans, metal and brick buildings, and the environment (kill trees and crops, change pH of soil, etc. See "Checking Out Acids and Bases" in ChemMatters, April 1983.]

  6. Why do some shampoo bottles say "acid-balanced"? [These shampoos claim to maintain the normal acid pH of hair and contain an acid, usually citric acid, to counteract the alkalinity of the detergents. See "Checking Out Acids and Bases" in ChemMatters, April, 1983.]

  7. What do antacids do? Are there any problems with taking too much? Antacids neutralize excess stomach acid brought on by stress, overeating, or disease. [Some antacids contain sodium ion (Alka Seltzer(TM)) which can aggravate hypertension. Milk of Magnesia, Mg(OH)2, in large doses has a laxative effect. See "Checking Out Acids and Bases" in ChemMatters, April 1983.]

Acids and Bases
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