2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Acids, Bases, and Salts in the Home Objectives Describe the chemical structures of soaps and detergents and explain how they work. Describe the chemical composition of bleach and its uses. Describe how an antacid reduces stomach acid. Identify acidic and basic household products and their uses. Chapter 8

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Acids, Bases, and Salts in the Home Bellringer Many acids, bases, and salts are used daily in our homes. Based on what you know about the properties of acids, bases, and salts, answer the following items. 1. Some green apples are particularly sour. Is this likely to be due to an excess of acid or base? 2. Baking soda reacts with vinegar. Is baking soda an acid or a base? 3. What products besides carbon dioxide remain after vinegar and baking soda react completely? 4. Given that one approach to an upset stomach is to take an antacid, are the chemicals secreted into the stomach for digestion likely to be acids or bases? 5. Drain cleaners that contain lye react with fatty acids in clogs. Given that, are drain cleaners that contain lye acids or bases? 6. Why does the clog dissolve after the reaction of the fatty acids with lye? 7. Many common window cleaners contain ammonia, a base. Given that, is most dirt on window slightly acidic or slightly basic? Chapter 8

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Acids, Bases, and Salts in the Home Cleaning Products Soap improves water’s ability to clean because it can dissolve in both oil and in water. This allows oil and water to form an emulsion that can be washed away by rinsing. Soaps are salts of sodium or potassium and fatty acids. When soap combines with certain cations, such as Mg 2+, Ca 2+, and Fe 3+, it can form soap scum. Detergents have replaced soap in many applications because they do not form scum. Chapter 8

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Acids, Bases, and Salts in the Home Cleaning Products, continued Many household cleaners contain ammonia, a weak base. Solutions of ammonia can clean away light grease smears. Household bleach is a solution of a strong base, sodium hypochlorite (NaOCl). You are probably familiar with bleach’s ability to whiten fabrics. Bleach is also a strong disinfectant, a chemical substance that kills harmful bacteria or viruses. Chapter 8

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bleach Section 3 Acids, Bases, and Salts in the Home Chapter 8

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Acids, Bases, and Salts in the Home Acids, Bases, and Salts in the Household An antacid is a weak base that neutralizes stomach acid. Sodium hydrogen carbonate and magnesium hydroxide (milk of magnesia) are examples. Shampoos are adjusted for an ideal pH. The pH of most shampoos is between 5 and 8. If shampoo is too basic, it can cause strands of hair to swell, giving them a dull, lifeless appearance. Chapter 8

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Antacid Section 3 Acids, Bases, and Salts in the Home Chapter 8

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Acids, Bases, and Salts in the Home Acids, Bases, and Salts in the Household, continued Acids keep fruit fresh longer. Acidic marinades made of vinegar or wine can be used to tenderize meats because they can denature proteins in the meat. Bacteria convert lactose, a sugar in milk, into lactic acid. The lactic acid denatures the protein casein in milk and changes the milk into yogurt. The strong base sodium hydroxide, also called lye, is used to unclog drains. Chapter 8

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concept Mapping Section 3 Acids, Bases, and Salts in the Home Chapter 8

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 1. What is the pH of a solution with a hydroxide ion concentration of 1  10 –13 M? A.–13 B.1 C.7 D.13 Standardized Test Prep Chapter 8

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 1. What is the pH of a solution with a hydroxide ion concentration of 1  10 –13 M? A.–13 B.1 C.7 D.13 Standardized Test Prep Chapter 8

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 2. Which of the following is true of weak acids? F.They are less soluble in water than strong acids. G.They do not ionize as completely in water as strong acids. H.They have a pH value that is lower than that of strong acids. I.They do not react with bases to form a salt as do strong acids. Standardized Test Prep Chapter 8

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 2. Which of the following is true of weak acids? F.They are less soluble in water than strong acids. G.They do not ionize as completely in water as strong acids. H.They have a pH value that is lower than that of strong acids. I.They do not react with bases to form a salt as do strong acids. Standardized Test Prep Chapter 8

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 3. Which of the following pH ranges would include the equivalence point of the titration of a strong acid with a weak base? A.pH 2 to pH 6 B.pH 6 to pH 8 C.exactly pH 7 D.exactly pH 8 Standardized Test Prep Chapter 8

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 3. Which of the following pH ranges would include the equivalence point of the titration of a strong acid with a weak base? A.pH 2 to pH 6 B.pH 6 to pH 8 C.exactly pH 7 D.exactly pH 8 Standardized Test Prep Chapter 8

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 4. What property of detergents makes them more useful than soap for washing clothes and dishes in many parts of the country? Standardized Test Prep Chapter 8

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 4. What property of detergents makes them more useful than soap for washing clothes and dishes in many parts of the country? Answer: Detergents do not form insoluble salts with calcium as do soaps, so they work better in hard water. Standardized Test Prep Chapter 8

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 5. How can you determine by tasting which foods have a high concentration of one or more acidic compounds? Standardized Test Prep Chapter 8

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Understanding Concepts 5. How can you determine by tasting which foods have a high concentration of one or more acidic compounds? Answer: Acidic compounds have a sour taste. Standardized Test Prep Chapter 8

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reading Skills Nitrogen and sulfur compounds formed by the combustion of fossil fuels react with oxygen and water in the air to form acids. These acids dissolve in water, forming acid precipitation, which can react with objects on which it falls. Limestone statues and decorations on buildings in areas with acidic rainfall have been severely damaged by the acid. On the other hand, granite statues and carvings tend to suffer much less damage under the same conditions. 6. Assess why one type of stone, limestone, is affected by acid precipitation much more than another type of stone, granite. Standardized Test Prep Chapter 8

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reading Skills, continued 6. Assess why one type of stone, limestone, is affected by acid precipitation much more than another type of stone, granite. Answer: Limestone reacts more with acid than granite. Therefore, the compounds that make up limestone must be basic, and those in granite are not. Standardized Test Prep Chapter 8

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Interpreting Graphics Standardized Test Prep 7. What is occurring between the addition of 10 mL and 20 mL of NaOH? F.Hydrogen ion concentration is increasing. G.Hydroxide ion concentration is increasing. H.Hydronium ion concentration is increasing. I.Hydrogen ion and hydroxide ion concentrations are increasing. Chapter 8

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Interpreting Graphics 7. What is occurring between the addition of 10 mL and 20 mL of NaOH? F.Hydrogen ion concentration is increasing. G.Hydroxide ion concentration is increasing. H.Hydronium ion concentration is increasing. I.Hydrogen ion and hydroxide ion concentrations are increasing. Standardized Test Prep Chapter 8