1. CHAPTER 25 Acids and Bases

2. Acids Substances that react with water to form hydronium ions H 3 O +. Properties of acids: –Taste sour –Corrosive –Poisonous –Affect indicators –Neutralize bases

3. Acids, cont. Examples of common acids: –Inorganic Acids-Acids made from minerals 1. Phosphoric Acid- H 3 PO 4 2. Sulfuric Acid-H 2 SO 4 3. Nitric Acid-HNO 3 4. Hydrochloric Acid- HCl

4. Acids, cont. –Organic Acid-Acids containing the carboxyl group 1. Vinegar or Acetic Acid-HC 2 H 3 O 2 2. Citric Acid-C 6 H 8 O 7 3. Malic Acid-C 4 H 6 O 5 4. Lactic Acid-C 3 H 6 O 3 5. Butyric Acid-C 4 H 8 O 2

5. Bases Substances that react with water to form hydroxide ions OH -. Properties of Bases: –Taste bitter –Feels slippery to the touch –Neutralizes acids –Affect indicators

6. Bases, cont. Examples of common bases: 1. Ammonia-NH 3 or NH 4 OH 2. Lye-NaOH 3. Baking Soda- NaHCO 3 4. Limestone-CaCO 3

7. Reactions between Acids and Bases Neutralization Reaction –A reaction between an acid and a base –Produces a salt plus water A salt is any compound containing a (+) metal and a (-) nonmetal. Examples of salts: 1. sodium chloride 2. iron (III) oxide 3. copper (II) carbonate

8. Reactions between Acids and Bases –Examples of neutralization reactions acid + base → salt + water 1. NaOH + HCl  NaCl + H 2 O 2. Ba(OH) 2 + 2HNO 3  Ba(NO 3 ) 2 +2H 2 O

9. pH Scale Measures the acidity and alkalinity (basic ness) of a substance. The scale ranges from: -acids: pH 0 – pH 6 -neutral: pH 7 -bases: pH 8 – pH 14

10. pH Scale

11. Indicators Substances that are color sensitive to pH. Types of Indicators: --pH papers: wide spectrum of color change due to pH’s. –Litmus paper: 1. blue litmus: -changes red in the presence of an acid -remains blue in the presence of a base

12. Indicators, cont. 2. red litmus paper: -changes blue in the presence of a base -remains red in the presence of an acid 3. Phenolphthalein -remains clear in the presence of an acid -turns hot pink or magenta in the presence of a base

13. Acid Rain Formed by the release of sulfur and nitrogen when fossil fuels are burned. They dissolve in the moisture in the atmosphere and return in the form of acid rain. Acid rain reacts with bases and undergo neutralization. They dissolve marble on statues and limestone on lake bottoms.