1. Chapter 22 Acids, Bases, and Salts
Section 1: Acids and Bases
Section 2: Strength of Acids and Bases
Section 3: Salts

2. Section 1: Acids and Bases
Standard 3: Demonstrate an understanding of various properties and classifications of matter.
Objectives:
Compare and contrast acids and bases and identify the characteristics they have.
Examine some formulas and uses of common acids and bases.
Determine how the process of ionization and dissociation apply to acids and bases.

3. Acids
Acid - a substance that produces hydrogen ions (H+) in a water solution.
All acids contain at least one H atom that can be removed when dissolved in water.
Examples:

4. Hydronium ion- is H3O+.
When an acid dissolves in water, H+ ions interact with water molecules to form H3O+

5. Properties of Acids Properties of acids: Sour taste Can burn skin
Corrosive
React with active metals (Zn and Mg) and form hydrogen gas & some other compound
Conduct electricity
Turn litmus paper red
pH less than 7

6. Common acids and their uses
Acetic Acid (CH3COOH) is in vinegar; used in preserving foods
ASA [Acetylsalicylic acid, C9H8O4] is main component of aspirin; used in pain relievers

7. Common acids
Ascorbic acid (C6H8O6) is vitamin C; found in citrus fruits
Carbonic acid is in soda pop; it makes pop carbonated. It is also dissolves rocks and is involved in cave formation

8. Common acids
Hydrochloric acid (HCl) is in your stomach to break down food. It is used in industry to clean steel in a process called pickling
Lactic acid (C3H6O3) is produced in muscles when you exercise too much too fast. It is also what makes milk go sour. In yogurt & buttermilk.
Nitric acid (HNO3) is colorless but turns yellow when exposed to light. Used in making fertilizers. Very nasty stuff.

9. Common acids
Phosphoric acid (H3PO4) is in soda pop, detergents, and fertilizers. Detergents that contain phosphates (PO43-) create pollution.
Sulfuric acid (H2SO4) is in car batteries. Will pull water from the air if left open. Used in making paper. Very nasty stuff also.

10. Common Acids
Common acids: citric acids (citric fruits), lactic acid (yogurt and milk), acetic acid (vinegar), HCl (stomach)

11. Detecting Acids and Bases
Indicator - organic compound that changes a certain color with acids and another color with bases.
ex) litmus paper is red in acid & blue in base
pH paper
phenolphthalein solution

12. Indicators
An indicator is an organic compound that changes color in acid and in base. Example: Litmus is red in acid and blue in base.

13. Bases
Base - substance that forms hydroxide ions, OH-, in a water solution.
A base is also defined as any substance that accepts H+ from acids

14. Properties of Bases Properties of Bases:
Crystalline solids in undissolved state
Bitter taste
Slippery feel
Can burn skin
Corrosive
Conduct electricity
pH greater than 7
Turn litmus paper blue

15. Common bases and their uses
Aluminum hydroxide [Al(OH)3] is a sticky gel-like material used as a water purifyer; used as an antacid, in water purification, and making fabrics.
Calcium hydroxide [Ca(OH)2] is in “lime” for gardens and lawns. Used in plaster and making leather products.
Magnesium hydroxide [Mg(OH)2] is in antacids and laxatives. In “milk of magnesia”.

16. Common bases
Sodium hydroxide [NaOH] is called “lye” and “caustic soda”. Used in making soap, oven cleaner, drain opener, fabrics, paper. Very nasty stuff
Ammonia [NH3] is very bad smelling; can damage lungs. Used in cleaners, fertilizers, and to make fabrics.

17. Common Bases
Common bases: sodium hydroxide and calcium hydroxide

18. Ionization of Acids
The acid ionizes (or separates) into ions and the hydrogen atom combines with a water molecule to form hydronium ions (H3O+).
The negative areas of water attract to the positive H in the acid to form H3O+.

19. Dissociation of Bases
When bases dissolve in water, the negative areas of nearby water molecules attract to the positive ion in the base.
The positive areas of nearby water molecules attract to the –OH of the base.

20. Ammonia Ammonia (NH3) is a base that does not contain –OH.
Ammonia molecule attracts a hydrogen ion from a water molecule, forming an ammonium ion (NH4+).

21. Review Questions
What does an acid produce in solution?

22. Review Questions What does an acid produce in solution?
An acid produces hydrogen ions in solution, which interact with water molecules to form hydronium ions.

23. Review Questions
Which changes color in acids and bases? What category of chemicals is it?
A. ammonia
B. antacid
C. detergent
D. Litmus paper

24. Review Questions
Which changes color in acids and bases? What category of chemicals is it?
D. Litmus paper; indicator

25. Review Questions
Any substance that forms __________ in a water solution is a base.
A. H3O+
B. OH -
C. H +
D. H2O

26. Review Questions
Any substance that forms __________ in a water solution is a base.
B. OH -

27. Review Questions
What is the pH range for acids?

28. Review Questions
What is the pH range for acids?
0 - 6

29. Review Questions
What is the pH range for bases?

30. Review Questions
What is the pH range for bases?
8 - 14

31. 6. Identify three important bases and describe their uses.

32. 7. If an acid donates H+ and a base produces OH-, what compound if likely to be produced when acids react with bases

33. Section 2: Strengths of Acids and Bases
Standard 3: Demonstrate an understanding of various properties and classifications of matter.
Indicators: 3.8
Objectives:
Determine what is responsible for the strength of an acid or a base.
Compare and contrast strength and concentration.
Examine the relationship between pH and acid or base strength.
Examine electrical conductivity.

34. Strength of Acids and Bases
The strength of an acid or base depends on how many acid or base particles dissociate into ions in water.

35. Strength of Acids and Bases
Strong acid- when it dissolves in water, nearly all the acid molecules dissociate into ions. Examples: HCl, HNO3, and H2SO4.
A strong acid solution conducts more current because more ions are formed. Light bulb is bright.

36. Weak acid- when it dissolves in water, only a small fraction of the molecules dissolve in water. Examples: acetic acid and carbonic acid
A weak acid solution does not conduct as much current because less ions are formed.Light bulb would be dim.

37. Strong and Weak Acids
Strong acid - nearly all the acid molecules dissociate into ions.
Weak acid - only a small fraction of the molecules dissolve in water.

38. Strong and Weak Bases
Strong base - dissociates completely in solution.
Weak base - does not dissociate completely.

39. Strength & Concentration
Strong and weak refer to the degree to which an acid or base ionizes
Dilute and concentrated are used to indicate the concentration of a solution, which is the amount of acid or base dissolved in the solution.

40. You can have a dilute solution of a strong acid
You can have a concentrated solution of a weak acid

41. pH pH - measure of the concentration of H+ ions in a solution.
The greater the H+ concentration  more acidic
Lower the H+ concentration  more basic

42. pH The pH scale ranges from 0 to 14.
pH less than 7 are acidic (more H+).
pH greater than 7 are basic (More OH-).
pH of 7 is neutral (H+ ions and OH- ions are equal).
Each value is 10x more or less acidic than the next
pH of blood must remain between 7.0 and 7.8

43. Detecting Acids and Bases
pH can be determined by using:
pH paper which changes color
pH meter
Indicators can tell if it’s an acid or base, but cannot tell you a pH

44. Buffers
Buffers - solutions containing ions that react with additional acids or bases to minimize their effects on pH.
Your blood has buffers that make it resistant to changes in pH.

45. Review Questions
What is the difference between a strong acid and a weak acid?

46. Review Questions
What is the difference between a strong acid and a weak acid?
In strong acids, nearly all the acid molecules dissociate into ions. In weak acids, a small fraction of the molecules dissolve in water.

47. Review Questions
What is the difference between the terms “strength” and “concentration”?

48. Review Questions
What is the difference between the terms “strength” and “concentration”?
Strength refers to the ease with which an acid or base dissociates in solution. Concentration is the amount of an acid or base dissolved in the solution.

49. Review Questions
The pH of a solution is a measure of the concentration of _________ in the solution.

50. Review Questions
The pH of a solution is a measure of the concentration of H+ in the solution.

51. Review Questions
(T/F) The lower the H+ concentration, the more basic the solution.

52. Review Questions
(T/F) The lower the H+ concentration, the more basic the solution.
True

53. Review Questions
What is the range of the pH scale?

54. Review Questions
What is the range of the pH scale?
0 - 14

55. Describe what determines the strength of an acid.
A base?

56. ~Depends on how many acid or base particles dissociate into ions in water

57. 7. Explain how to make a dilute solution of a strong acid.

58. 8. Explain how electricity can be conducted by solutions

59. More ions a solution contains, the more current it can conduct.

60. 9. Describe pH values of
9.1,
1.2, and
5.7
as basic, acidic, or very acidic.

61. 1.2: very acidic
5.6: acidic
9.1: basic

62. How much more acidic is a solution of pH 2 than a solution of pH 4?

63. 100

64. Section 3: Salts
Standard 3: Demonstrate an understanding of various properties and classifications of matter.
Indicators: 3.8
Objectives:
Identify a neutralization reaction.

65. Neutralization
Neutralization - chemical reaction between an acid and a base that takes place in a water solution.

66. Salt Formation
Salt - a compound formed when the negative ions from an acid combine with the positive ions from a base.

67. Neutralization Reaction
Acid + Base  Salt + Water

68. Common salts & uses

69. Titration
Titration is the process in which a solution of known concentration (standard solution) is used to determine the concentration of another solution.

70. Titration
Video Clip

71. Natural Indicators Many natural substances are acid-base indicators.
ex) red cabbage, radishes, roses

72. Soaps are are organic salts
Soaps are are organic salts. The nonpolar organic chain of carbon atoms on one end and either a sodium or potassium salt of a carboxylic acid group at the other end

74. Review Questions
What is the neutralization reaction?

75. Review Questions What is the neutralization reaction?
Acid + Base  Salt + Water

76. Review Questions
A compound formed when the negative ions from an acid combine with the positive ions from a base is called a __________.

77. Review Questions
A compound formed when the negative ions from an acid combine with the positive ions from a base is called a salt.

78. Review Questions
(T/F) Many natural substances are acid-base indicators.

79. Review Questions
(T/F) Many natural substances are acid-base indicators.
True

80. Review Questions
__________ is the process in which a solution of known concentration (standard solution) is used to determine the concentration of another solution.

81. Review Questions
Titration is the process in which a solution of known concentration (standard solution) is used to determine the concentration of another solution.

82. Review Questions
A chemical reaction between an acid and a base that takes place in a water solution is called a(n) __________.

83. Review Questions
A chemical reaction between an acid and a base that takes place in a water solution is called a(n) neutralization reaciton.