1. Chapter 19: Acids and Bases
Table of Contents
Chapter 19: Acids and Bases
19.1: Acids and Bases
19.2: Strengths of Acids and Bases
19.3: What is pH?
19.4: Neutralization

2. Chapter 19: Acids and Bases
Table of Contents
Chapter 19: Acids and Bases
19.1: Acids and Bases

3. Properties of Acids and Bases
Acids and Bases: Basic Concepts
Properties of Acids and Bases
ACIDS
BASES
sour
bitter
slippery
Turn litmus red
Turns litmus blue
Don’t react with metals
React with & corrodes metals
Lemon juice, vinegar, etc.
Soaps, etc.

4. H is the first element in a formula
Acids and Bases: Basic Concepts
The Arrhenius model
Acids
H is the first element in a formula
Ionizes in aqueous solution to form H+ ions
Increases the concentration H+ ions
Also can produce hydronium ion, H3O+.

5. Hydrolysis: HCl dissolves in water, produces hydronium ions
Acids and Bases: Basic Concepts
The Arrhenius model
Hydrolysis: HCl dissolves in water, produces hydronium ions
In an acid, any hydrogen atom that can be transferred to water is called an acidic hydrogen.

6. Monoprotic acids contain only one acidic hydrogen.
Acids and Bases: Basic Concepts
Monoprotic Acids
Monoprotic acids contain only one acidic hydrogen.

7. Diprotic and Triprotic Acids
Acids and Bases: Basic Concepts
Diprotic and Triprotic Acids
Polyprotic acids: contains several acidic hydrogens.
Diprotic acids: contain two acidic hydrogens.
Triprotic acids: contain three acidic hydrogens.

8. Base: produces hydroxide ions (OH –) when it dissolves in water.
Acids and Bases: Basic Concepts
Arrhenius Bases
Base: produces hydroxide ions (OH –) when it dissolves in water.
The simplest kind: water-soluble ionic compound (like NaOH) that contains the hydroxide ion as the negative ion.
Dissociates in solution to release OH-

9. Chapter 19: Acids and Bases
Table of Contents
Chapter 19: Acids and Bases
19.2: Strengths of Acids and Bases

10. Strength Is Not Concentration
Acids and Bases: Basic Concepts
Strength Is Not Concentration
weak and strong: compare the strengths of acids and bases
dilute and concentrated: describe the concentration of solutions.
The combination of strength and concentration ultimately determines the behavior of the solution.

11. Completely dissociates in water
Acids and Bases: Basic Concepts
Strong Bases & Acids
Strong Acids and Bases
Completely dissociates in water
Completely breaks into ions
Mg(OH)2(aq)→ Mg2+(aq) + 2OH–(aq)
HCl(aq)→ H+(aq) + Cl–(aq)

12. List of strong acids and bases
HCl – hydrochloric acid
HBr - hydrobromic acid
HI – hydroiodic acid
HNO3 – nitric acid
H2SO4 – sulfuric acid
HClO4 – perchloric acid
Groups 1 & 2
NaOH
KOH
LiOH
RbOH
CsOH
Ca(OH)2
Ba(OH)2
Sr(OH)2

13. Most molecules don’t react with water to break into ions
Acids and Bases: Basic Concepts
Weak Bases & Acids
Weak Acids and Bases
Reaches equilibrium
Most molecules don’t react with water to break into ions
Acetic acid (HC2H3O2); HCHO2
Ammonia (NH3); Al(OH)3; Fe(OH)3

14. Acids and Bases: Basic Concepts
Weak Acids
The concentration of the un-ionized acid is always the greatest of the three concentrations. (Comparing strong acids and weak acids)

15. A Broader Definition of Acids and Bases Brønsted-Lowry model
Acids and Bases: Basic Concepts
A Broader Definition of Acids and Bases
Brønsted-Lowry model
Acid = a proton (hydrogen-ion) donor
When a Brønsted-Lowry acid donates a hydrogen ion, a conjugate base is formed.
Base = a proton (hydrogen-ion) acceptor
When a Brønsted-Lowry base accepts a hydrogen ion, a conjugate acid is formed.

16. A Broader Definition of Acids and Bases
Acids and Bases: Basic Concepts
A Broader Definition of Acids and Bases
Conjugate acid-base pair: Two substances related to each other by the donating and accepting of a single hydrogen ion.
Acid – conjugate base
strong
weak
weak
strong
Base – conjugate acid

17. Identifying Conjugate Acid-Base Pairs
Acids and Bases: Basic Concepts
Identifying Conjugate Acid-Base Pairs
Identify the conjugate acid-base pairs in this reaction.
conjugate base
acid
(donates H+)
base
(accepts H+)
conjugate acid

18. PRACTICE identifying CA & CB
NH4+(aq) + OH-(aq) NH3(aq) + H2O(l)
CO32-(aq) + H2O(l) HCO3-(aq) +OH-(aq)
HSO4-(aq) + H2O(l) H3O+(aq) +SO42-(aq)
acid
base CB CA
base
acid CA CB
acid
base CA CB
Fin de la première journée

19. Fin de la 1ère journée

20. Chapter 19: Acids and Bases
Table of Contents
Chapter 19: Acids and Bases
19.3: What is pH?

21. Today, you’ll need a scientific/graphing calculator!
Acids and Bases: Basic Concepts
Starter
Define Arrhenius and Brønsted-Lowry acids and bases
What is the difference between weak and strong acids and bases?
What are some characteristics of acids? bases?
Today, you’ll need a scientific/graphing calculator!

22. The ion product constant for water
Acids and Bases: Basic Concepts
The ion product constant for water
Self-ionization of water:
H2O(l) H+(aq) + OH-(aq)
2H2O(l) H3O+(aq) + OH-(aq)
Kw =
[H+][OH-]
= 1.0x10–14
Just “plug and chug” to solve for concentrations of either ion

23. The ion product constant for water
Acids and Bases: Basic Concepts
The ion product constant for water
When [H+] > [OH-], the solution is acidic
When [H+] < [OH-], the solution is basic
When [H+] = [OH-], the solution is neutral

24. Practice finding [H+] & [OH-]
The concentration of either the H+ ion or OH- ion is given. For each solution, calculate [H+] or [OH-]. State whether the solution is acidic, basic, or neutral.
1. [H+] = 1.0x10-5M
2. [H+] = 1.0x10-13M
3. [OH-] = 1.0x10-7M
4. [OH-] = 1.0x10-3M
[OH-] = 1.0x10-9M, acidic
[OH-] = 1.0x10-1M, basic
[H+] = 1.0x10-7M, neutral
[H+] = 1.0x10-11M, basic

25. Indicators register different colors at different pHs.
Acids and Bases: Basic Concepts
Measuring pH
pH measures acidity.
Indicators register different colors at different pHs.
pH meters are instruments that measure the exact pH of a solution.

26. Measures concentration of hydronium (H3O+) ions in a solution
Acids and Bases: Basic Concepts
The pH Scale
pH:
A mathematical scale
Measures concentration of hydronium (H3O+) ions in a solution
Range: 0 to 14

27. Interpreting the pH Scale pH = 7 is neutral.
Acids and Bases: Basic Concepts
Interpreting the pH Scale
pH = 7 is neutral.
pH < 7 is acidic. As pH drops from 7, it becomes more acidic.
pH > 7 is basic. As pH increases from 7, the solution becomes more basic.

28. The pH Scale [H+] = 1x10–11M pH =11 [H3O+] = 1x10–4M pH = 4
Acids and Bases: Basic Concepts
The pH Scale
[H+] = 1x10–11M
pH =11
[H3O+] = 1x10–4M
pH = 4
[H3O+] = 1.1x10–4M
pH = 3.96

29. pH scale: expresses the acidity of a solution.
Acids and Bases: Additional Concepts
pH and pOH
pH scale: expresses the acidity of a solution.
pOH scale: expresses the basicity of a solution.

30. Acids and Bases: Additional Concepts
pH and pOH
The pH and pOH values for a solution may be determined if either [H+] or [OH–] is known.

31. CALCULATING pH and pOH from [H+]
Acids and Bases: Additional Concepts
CALCULATING pH and pOH from [H+]
EXAMPLE: If a carbonated soft drink has a hydrogen ion concentration of 7.3 x 10–4M, what are the pH and pOH of the soft drink?
Known: [H+] Calculate pH

32. CALCULATING pH and pOH from [H+]
Acids and Bases: Additional Concepts
CALCULATING pH and pOH from [H+]
The carbonated soft drink is acidic.

33. Practice calculating pH and pOH
Calculate the pH and pOH of aqueous solutions having the following ion concentrations.
1. [OH-] = 1.0x10-6M
2. [OH-] = 6.5x10-4M
3. [H+] = 3.6x10-9M
4. [H+-] = M
pOH = 6.00, pH = 8.00
pOH = 3.19, pH = 10.81
pH = 8.44, pOH = 5.56
pH = 1.60, pOH = 12.40

34. Fin de la 2ème journée On WebAssign Ch 19, SKIP 3, 11, 18, 20, 21
We will correct Ch 19 practice problems 1-12 tomorrow at the beginning of class

35. pH + pOH = 14 pH
pOH
pH=-log[H+]
pOH=-log[OH-]
[H+]
[OH-]
1.0x10-14 = [H+][OH-]

36. WARM-UP [OH-] = 6.5x10-4M [H+-] = 0.025 M pOH = 3.19, pH = 10.81
Calculate the pH and pOH of aqueous solutions having the following ion concentrations.
[OH-] = 6.5x10-4M
[H+-] = M
pOH = 3.19, pH = 10.81
pH = 1.60, pOH = 12.40
The concentration of either the H+ ion or OH- ion is given. For each solution, calculate [H+] or [OH-]. State whether the solution is acidic, basic, or neutral.
[H+] = 1.0x10-5M
[OH-] = 1.0x10-3M
[OH-] = 1.0x10-9M, acidic
[H+] = 1.0x10-11M, basic

37. [H+] = 10-pH [OH-] = 10-pOH CALCLUATING ion concentrations from pH
Acids and Bases: Additional Concepts
CALCLUATING ion concentrations from pH
[H+] = 10-pH
[OH-] = 10-pOH

38. Acids and Bases: Additional Concepts
Calculating [H+] and [OH–] from pH
What are [H+] and [OH–] in a solution with a pH of 9.70?
Find [H+].
[H+] = 10-pH =
[H+] = 2.0 x 10–10 M

39. Calculating [H+] and [OH–] from pH
Acids and Bases: Additional Concepts
Calculating [H+] and [OH–] from pH
What are [H+] and [OH–] in a solution with a pH of 9.70?
Determine pOH

40. As expected, [OH–] > [H+] in this basic solution.
Acids and Bases: Additional Concepts
Calculating [H+] and [OH–] from pH
What are [H+] and [OH–] in a solution with a pH of 9.70?
Find [OH–]
[OH-] = 10-pOH =
As expected, [OH–] > [H+] in this basic solution.

41. Practice finding ion concentrations
The pH is given for three solutions. Calculate [H+] and [OH-] in each solution.
1. pH = 2.37
2. pH = 11.05
3. pH = 6.50
[H+] =4.3x10-3 M
[OH-]=2.3x10-12 M
[H+] = 8.9x10-12 M
[OH-]=1.1x10-3 M
[H+] =3.2x10-7 M
[OH-]=3.2x10-8 M

42. CALCLUATING pH of strong acids and bases
Acids and Bases: Additional Concepts
CALCLUATING pH of strong acids and bases
Remember, strong acids and bases completely break into their ions in water
HCl(aq)→ H+(aq) + Cl–(aq)
For every HCl molecule, 1 H+ ion is produced. So, [H+] = [HCl]
Mg(OH)2(aq)→ Mg2+(aq) + 2OH–(aq)
For every Mg(OH)2 molecule, 2 OH- ions are produced. So, [Mg(OH)2] = 2[OH-]

43. Practice calculating pH of SA & SB
Calculate the pH of the following solutions.
1) 1.0 mol/L HI
2) mol/L HNO3
3) 1.0 M KOH
4) 2.4x10-5 M Mg(OH)2
pH = 0.00
pH = 1.30
pH = 14.00
pH = 9.68

44. pH + pOH = 14 pH
pOH
pH=-log[H+]
pOH=-log[OH-]
[H+]=10-pH
[OH-]=10-pOH
[H+]
[OH-]
1.0x10-14 = [H+][OH-]

45. Fin de la 3ème journée
We will correct and turn in Ch 19 practice problems tomorrow at 1:40
WebAssign Ch 19 is due Thursday, 17 May
On WebAssign Ch 19, SKIP 3, 11, 18, 20, 21

46. Chapter 19: Acids and Bases
Table of Contents
Chapter 19: Acids and Bases
19.4: Neutralization

47. Types of Acid-Base Reactions
Acids and Bases: Basic Concepts
Types of Acid-Base Reactions
The reaction of an acid and a base is called a neutralization reaction.
Strong acid + strong base → salt + water

48. Reactant: known molarity + unknown molarity →
Acids and Bases: Additional Concepts
Acid-Base Titrations
Acid-base titration: The process of determining the molarity of an acid or a base through the use of an acid-base reaction.
Reactant: known molarity + unknown molarity →
Standard solutions: Solutions of known molarity used in titrations.
The known reactant molarity is used to find the unknown molarity of the other solution.

49. Acids and Bases: Additional Concepts
Acid-Base Titrations
Indicator: A substance used to “locate” the equivalence point of a titration. (endpoint –color change)
Equivalence point: the point in the reaction where stoichiometrically equal amounts of acid and base have been added
For weak base-strong acid reaction, mixing equal moles of acid and base does not produce a neutral solution.

51. MbaseVbase=MacidVacid
Acids and Bases: Additional Concepts
Acid-Base Titrations
Titration/Neutralization calculations
MbaseVbase=MacidVacid
Plug and Chug!

52. Determining Concentration: Using Stoichiometry
Acids and Bases: Additional Concepts
Determining Concentration: Using Stoichiometry
EXAMPLE: A 0.100M LiOH solution was used to titrate an HBr solution of unknown concentration. At the endpoint, 21.0 mL of LiOH solution had neutralized 10.0 mL of HBr. What is the molarity of the HBr solution?
MbVb = MaVa
(0.100M)(21.0mL) =
(? M)(10.0mL)
0.210M HBr

53. Practice Titrations
A M LiOH solution was used to titrate an HBr solution of unknown concentration. At the endpoint, 75.0 mL of LiOH solution had neutralized 25.0 mL of HBr. What is the molarity of the HBr solution?
100 mL of 0.75 M HCl is used to titrate 150 mL NaOH. What is the concentration of NaOH?
1.05 M HBr
0.5 M NaOH

54. Which turned basic first, the acid or the buffer?
Acids and Bases: Additional Concepts
Buffers
Click box to view movie clip.
How was the buffer made?
Which turned basic first, the acid or the buffer?
What is the definition of a buffer?

55. Buffer: a solution that resists changes in pH.
Acids and Bases: Additional Concepts
Buffers Defined
Buffer: a solution that resists changes in pH.
Buffer solutions are prepared by using a weak acid or base with one of its salts (its conjugate base/conjugate acid)
When you add base to an acidic buffer, the base will react with the salt – not the acid, maintaining pH.

56. End Ch. 19
We will correct and turn in Ch 19 practice problems TODAY at 1:40.
WebAssign Ch 19 is due Thursday, 17 May

57. Universal Indicator

58. Types of Acid-Base Reactions
Acids and Bases: Basic Concepts
Types of Acid-Base Reactions
The reaction of an acid and a base is called a neutralization reaction.
Click box to view movie clip.

59. Neutralization Reactions
Acids and Bases: Basic Concepts
Neutralization Reactions
Strong acid + strong base → salt + water
Click box to view movie clip.

60. Acids and Bases: Additional Concepts
Acid-Base Titrations
Acid-base titration: The process of determining the molarity of an acid or a base through the use of an acid-base reaction.
Click box to view movie clip.