1. Acids and Bases

2. HCl + H2O  H3O+ + Cl– Arrhenius – + Acids form hydronium ions (H3O+)
Arrhenius - In aqueous solution…
Acids form hydronium ions (H3O+)
HCl + H2O  H3O+ + Cl– H Cl O – +
acid

3. NH3 + H2O  NH4+ + OH- Arrhenius – + Bases form hydroxide ions (OH-)
Arrhenius - In aqueous solution…
Bases form hydroxide ions (OH-)
NH3 + H2O  NH4+ + OH- H N O – +
base

4. HCl + H2O  Cl– + H3O+ Bronsted-Lowry acid conjugate base base
Acids are proton (H+) donors.
Bases are proton (H+) acceptors.
HCl + H2O  Cl– + H3O+
acid
conjugate base
base
conjugate acid

5. Definitions
H2O + HNO3  H3O+ + NO3– B A CA CB

6. Amphoteric - can be an acid or a base.
Definitions
NH3 + H2O  NH4+ + OH- B A CA CB
Amphoteric - can be an acid or a base.

7. Polyprotic - an acid with more than one H+
Give the conjugate base for each of the following:
HF H3PO4 H3O+
F - H2PO4- H2O
Polyprotic - an acid with more than one H+

8. Br - HSO4- CO32- HBr H2SO4 HCO3-
Give the conjugate acid for each of the following:
Br - HSO4- CO32-
HBr H2SO4 HCO3-

9. Lewis Acids are electron pair acceptors.
Bases are electron pair donors.
Lewis base
Lewis acid

10. Properties ACIDS BASES electrolytes  electrolytes sour taste
bitter taste
turn litmus red
turn litmus blue
react with metals to form H2 gas
slippery feel
vinegar, milk, soda, apples, citrus fruits
ammonia, lye, antacid, baking soda
ChemASAP

11. Properties of Acids Acids taste sour Acids effect indicators
Blue litmus turns red
Phenolphthalein turns clear/colorless
Acids have a pH lower than 7
Acids are proton (hydrogen ion, H+) donors
Acids react with active metals, produce H2
Acids react with carbonates
Acids neutralize bases

12. Acids to know: Strong Acids Weak Acids Sulfuric acid, H2SO4
Phosphoric acid, H3PO4
Hydrochloric acid, HCl
Acetic acid, HC2H3O2
Nitric acid, HNO3

13. Nitric Acid Used in the production of fertilizers
Used in the production of explosives
Nitric acid is a volatile acid – its reactive components evaporate easily
Stains proteins (including skin!)

14. Acetic Acid Used in the manufacture of plastics
Used in making pharmaceuticals
Acetic acid is the acid present in vinegar

15. Acids are Proton Donors
Monoprotic acids
Diprotic acids
Triprotic acids
H3PO4
HCl
H2SO4
HC2H3O2
H2CO3
HNO3

16. Ionization of HCl and formation of hydronium ion, H3O+
H2O + HCl 
H3O+ + Cl-
Proton
acceptor
Proton
donor

17. Strong vs Weak & Concentrated vs Dilute
From last unit
Concentrated: A lot of solute has been dissolved
Dilute: A small amount of solute has been dissolved
THESE HAVE TO DO WITH AMOUNT DISSOLVED
From this unit
Strong: substance breaks up completely into ions
Dilute: substance does not break up completey into ions
THIS HAS NOTHING TO DO WITH HOW MUCH!
If you had only 1 molecule, but it was broken into ions, it would be strong!

18. STRONG ACID WEAK ACID STRONG BASE WEAK BASE

19. Strong Acids vs. Weak Acids
Strong acids are assumed to be 100% ionized in solution (good proton donors).
HCl
H2SO4
HNO3
Weak acids are usually less than 5% ionized in solution (poor proton donors).
H3PO4
HC2H3O2
Organic acids

20. Strong Acid Dissociation

21. Weak Acid Dissociation

22. ConcepTest
Which of the following "molecular" pictures best represents a concentrated solution of the weak acid HA? A B

23. Acids Effect Indicators
Blue litmus paper turns red in contact with an acid.
Phenolphthalein turns clear/colorless in an acid.

24. Acids have a pH less than 7

25. Products of Neutralization
HCl + NaOH 
NaCl + H2O
H2SO4 + Ca(OH)2 
CaSO H2O
HNO3 + KOH 
KNO3 + H2O
The products of neutralization are always a ______ and _______.
salt
water

26. Properties of Bases Bases effect indicators Red litmus turns blue
Bases taste bitter
Bases effect indicators
Red litmus turns blue
Phenolphthalein turns pinkish
Bases have a pH greater than 7
Bases are proton (hydrogen ion, H+) acceptors
Solutions of bases feel slippery
Bases neutralize acids

27. Examples of Bases Sodium hydroxide (lye), NaOH
Potassium hydroxide, KOH
Magnesium hydroxide, Mg(OH)2
Calcium hydroxide (lime), Ca(OH)2

28. Bases Effect Indicators
Red litmus paper turns blue in contact with a base.
Phenolphthalein turns purple/pink in a base.

29. Bases have a pH greater than 7

30. Bases Neutralize Acids
Milk of Magnesia contains magnesium hydroxide, Mg(OH)2, which neutralizes stomach acid, HCl.
2 HCl + Mg(OH)2
MgCl2 + 2 H2O

31. Self-Ionization of Water
H2O + H2O  H3O+ + OH-

32. Ion Concentration in Water

33. Kw – Ionization Constant for Water
In pure water at 25 C:
[H3O+] = 1 x 10-7 mol/L (M)
[OH-] = 1 x 10-7 mol/L (M)
Kw is a constant at 25 C:
Kw = [H3O+][OH-]
Kw = (1 x 10-7)(1 x 10-7) = 1 x M2

34. Concentrations of H3O+ and OH-
Since [H3O+] = [OH-] in pure water, it is neutral. When [H3O+]  [OH-] , the solution is acidic. When [H3O+]  [OH-], the solution is basic.

35. Concentrations of H3O+ and OH-
Kw = [H3O+] [OH- ] = 1.0 x M2
[H3O+] = Kw = X M2
[OH-] [OH-]
[OH -] = Kw = X M2
[H3O+] [H3O+ ]
Assume that strong acids and bases are completely ionized in solution

36. Examples of Calculating [H3O+] and [OH-]
Kw = 1.0 x M2 = [H3O+] [OH-] EX. If you have 2.0 x 10-4 M H3O+, then Kw = 1.0 x M2 = (2.0 x 10-4 ) x [OH-] [OH-] = Kw = 1.0 x M2 = 0.5 x M OH- [H3O+] 2.0 x 10-4 M

37. Calculating [H3O+] and [OH-]
Kw = 1.0 x M2 = [H3O+] [OH-] From the previous slide: [OH-] = 0.5 x M [H3O+] = 2.0 x 10-4 M [H3O+]  [OH-] , the solution is acidic.

38. pH Scale
Expressing the acidity or alkalinity in terms of concentration (how much—concentrated or dilute) of ions can be cumbersome since the values tend to be small.
A more convenient way to express concentration is to use pH:
pH “hydrogen power”
(French “pouvoir hydrogene”)

39. pH Scale pH INCREASING ACIDITY INCREASING BASICITY NEUTRAL
a measure of the concentration of H3O+ ions in solution
measured with a pH paper, pH meter or an indicator with a wide color range
Ranges from 0-14
Each number is 10x more concentrated than the next. (2 has 10x more H3O+ ions than 3)
INCREASING
ACIDITY
INCREASING
BASICITY
NEUTRAL

40. pH Scale
The pH of a solution is defined as the negative of the common logarithm of the hydronium ion concentration. [H3O+]
pH is expressed by the following:
pH = - log [H3O+]
The common logarithm of a number is the power to which 10 must be raised to equal the number.

41. pH Scale EX. [H3O+] = 1.0 x 10-5 M pH = 5
When the concentration of [H3O+] in solution is an integral power of 10, such as 1M or 0.01 M = 1.0 x 10-2, the pH of the solution is the exponent of the hydronium ion’s concentration with the sign changed.
EX. [H3O+] = 1.0 x 10-5 M
pH = 5

42. pH Scale pH = - log [H3O+] = -log (1.0 x 10 -7) = -(-7) = 7 Example:
A neutral solution has a [H3O+] of 1.0 x 10-7
The pH is determined as follows:
pH = - log [H3O+] = -log (1.0 x 10 -7) = -(-7) = 7

43. pH Scale A neutral solution would have [OH-] = 1.0 x 10-7 M.
pOH can also be determined, however it can only be determined from [OH-] concentration
pOH = - log [OH-]
A neutral solution would have [OH-] = 1.0 x 10-7 M.
Therefore, the pOH = 7
pH + pOH = 14.0

44. pH and pOH Calculations

45. pH SCALE OF COMMON
HOUSEHOLD PRODUCTS

46. Sample Problem: What is the pH of a 1.0 x 10-3 M NaOH solution?
Since [NaOH] is 1x10-3 M, and it’s a 1:1 ratio of Na:OH, then [OH-]=1.0x10-3
Using this we can solve for pOH
Once we have pOH, then pH=14-pOH

47. Sample Problem What is the pH of a solution if the [H3O+] is
3.4 x 10-5 M?
Use the calculator to find:
pH = -log [H3O+] = -log (3.4 x 10-5 )

48. Finding [H3O+] and [OH-] from pH and pOH
[H3O+] = 10 (-pH)
[OH-] = 10 (-pOH)

49. Sample Problem
What is the [OH-] of a solution whose pH = 3.00?

50. Formulas! Finding [H3O+] and [OH-] Finding pH and pOH
[H3O+] = Kw
[OH-]
[OH -] = Kw
[H3O+]
Finding pH and pOH
pH = -log (H3O+)
pOH = -log (OH-)
pH + pOH = 14
Finding [H3O+] and [OH-] from pH, pOH
[H3O+] = 10 (-pH)
[OH-] = 10 (-pOH)

51. H+, OH-, and pH

52. pH Scale

53. pH + pOH = 14

54. Measuring pH with wide-range paper

55. Narrow-Range pH Paper

56. pH Indicators and their ranges

57. Neutralization & Titrations
ACID + BASE  SALT + WATER
HCl + NaOH  NaCl + H2O
strong
strong
neutral
HC2H3O2 + NaOH  NaC2H3O2 + H2O
weak
strong
basic
Salts can be neutral, acidic, or basic.
Neutralization does not mean pH = 7.

58. If you have equal amounts…
Strong Acid + Strong Base = Neutral (pH=7)
Strong Acid + Weak Base = Acidic (pH < 7)
Weak Acid + Strong Base = Basic (pH>7)

59. Titration
standard solution
unknown solution
Titration
Process in which a standard solution is used to determine the concentration of an unknown solution.

60. Titration dramatic change in pH Equivalence Point
Point at which equal amounts of H3O+ and OH- have been added.
Determined by…
indicator color change
dramatic change in pH

61. Equivalence point The equivalence point is not always neutral
When strong base reacts with strong acid, EP is neutral
When strong base reacts with a weak acid or strong acid reacts with weak base, EP will not be at pH 7

62. Equivalence points Weak Acid titrated with strong base
Weak base titrated with strong acid

64. moles H3O+ = moles OH- MV n = MV n
Titration
moles H3O+ = moles OH-
MV n = MV n
M: Molarity
V: volume
n: # of H+ ions in the acid or OH- ions in the base

65. Titration H3O+ M = ? V = 50.0 mL n = 2 OH- M = 1.3M V = 42.5 mL n = 1
42.5 mL of 1.3M KOH are required to neutralize 50.0 mL of H2SO4. Find the molarity of H2SO4.
H3O+
M = ?
V = 50.0 mL
n = 2
OH-
M = 1.3M
V = 42.5 mL
n = 1
MV# = MV#
M(50.0mL)(2)
=(1.3M)(42.5mL)(1)
M = 0.55M H2SO4

66. Or you can solve by setting up factor label
mL KOH  L KOH  moles KOH (using molarity 1.3 moles / 1 liter)  moles of H2SO4 (from rxn stoich ratios)
Then divide moles H2SO4 by volume H2SO4 in L (change from mL)