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CHAPTER 25 Acids, Bases and Salts.

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Presentation on theme: "CHAPTER 25 Acids, Bases and Salts."— Presentation transcript:

1 CHAPTER 25 Acids, Bases and Salts

2 Section 1-Acids and Bases
Acid—a substance that produces hydrogen ions in a water solution (H donor) It is the ability to produce these ions that gives acid their characteristic properties Properties: sour taste, corrosive, react strongly w/certain metals, turns litmus red

3 Common Acids Citric acid—found in citrus fruits
Lactic acid—found in yogurt and buttermilk Acetic acid—vinegar (pickles Hydrochloric acid—in your stomach Others used in industry: sulfuric, phosphoric, nitric and hydrochloric

4 Bases Base—any substance that forms hydroxide ions, OH, in a water solution OR any substance that accepts H from acids (H acceptor) Properties: many are crystalline solids, feel slippery, taste bitter, can be corrosive, turns litmus blue

5 Common examples of Bases:
Ex: egg whites, baking powder, milk of magnesia, antacids, ammonia, etc. Chart-pg. 769

6 Solutions of Acids and Bases
Compounds that can form hydroxide ions in solution are bases These substances release OH ions in water. **If a solution contains MORE OH ions than H3O ions, it is referred to as BASIC Ammonia in solution—pg. 771 (harmful effects of ammonia w/other cleaners)

7 Solutions of both acids and bases produce some ions that are capable of carrying electric current to some extent- **These solutions are said to be CONDUCTORS

8 Section 2—Strength of Acids & Bases
The strength of an acid or base depends on how completely a compound separates into ions when dissolved in water Strong acid—an acid that ionizes almost completely in solution Ex: HCl, HNO3 and H2SO4 Weak acid—an acid that only partly ionizes Ex: acetic and carbonic acids

9 Bases: Strong base—dissociates completely in solution
Ex: sodium hydroxide Weak base—one that does not ionize completely ex: Ammonia Remember: Strong and Weak acids and bases are not to be confused with DILUTION and CONCENTRATION of acids and bases

10 pH of a Solution pH—a measure of the concentration of H ions in a solution The greater the H concentration is, the lower the pH is and the more acidic the solution pH—measures how acidic or bassic a solution is

11 pH Scale pH scale—ranges from 0 to 14 0-most acidic 14-most basic
7-neutral Universal indicator paper—can be sued to determine pH of substances (colors are matched to determine pH level)

12 pH meter-can be used to determine the pH of a solution more precisely
Operated by immersing electrodes in the solution and reading a dial Blood pH—pH of blood must remain between 7.0 and 7.8 Buffers—help keep your blood close to a nearly constant pH of 7.4 (neutralizers)

13 Section 3: Salts Neutralization: a chemical reaction between an acid and a base that takes place in a water solution Salt: a compound formed when the negative ions from an acid combine w/the positive ions from a base Acid + Base- Salt + Water

14 Salts Are essential for many animals large and small
Most are composed of a positive metal ion and an ion with a negative charge Salts also form when acids react with metals (a single displacement reaction) Visualizing Salt—pg. 779

15 Titration Titration: a process in which a solution of known concentration is used to determine the concentration of another solution Ex: using phenolphthalein to determine concentration of acid/base solution—pg 780 Natural indicators: red cabbage, radishes, roses, hydrangeas, grape juice, etc.

16 Soaps and Detergents Soap: organic salts with a nonpolar organic chain of carbon atoms on one end, and either a sodium or potassium salt of a carboxylic acid at the other end Ex: pg. 782

17 Detergents Like soaps, detergents have long hydrocarbon chains, but instead of a carboxylic acid group, have a either a sulfonic acid or phosphoric acid group These acids form more soluble salts in hard water and lessen the soap scum problem Problems: pg. 783

18 Esters: Can be thought of as the organic counterparts of salts
Are made from acids, and water is formed in the reaction used to prepare them However, salts are made from bases and ESTERS are made from alcohols that are not bases but have a hydroxyl group Uses: perfumes, soaps, fibers, flavoring in drinks, etc.

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