1. Acids and Bases

2. Acids – Arrhenius Definition
Produce Hydronium ion (H3O+1) in water
Hydronium ion is water + a hydrogen cation H O
water H O +1 H +1
By this definition, if an acid is to give a H+1 to water, then all acids will have hydrogen as the cation (first element written).

3. How do Acids produce Hydronium Ions?-
water
acid
Hydrogen cation with some anion

4. How do Acids produce Hydronium Ions?- +1 H O

5. How do Acids produce Hydronium Ions?- +1 H O
Hydronium ion
Anion

6. Properties of Acids
You eat acidic things every day. Acids have a sour taste, like orange juice, lemonade and vinegar (ketchup).
Acids are also a main component of soft drinks, like Pepsi and Coke.
Your body uses acids to dissolve foods in your stomach.

7. Properties of acids
Acids are used to dissolve metals and turn them from the elemental metal into the ionic cation. When metals are dissolved, hydrogen gas is released.
Because they can dissolve and eat through many things, acids are considered corrosive.

8. Bases Bases are the opposite of acids.
Bases are defined as a chemical substance that accepts a proton.
Bases have extra electrons that they share with a lone proton that has no electrons.
The proton is accepted by the base, and forms a covalent bond.

9. Bases – Arrhenius Definition
Bases produce the hydroxide ion in water H O -1
Hydroxide Ion

10. Properties of Bases
Bases have a bitter taste. Dark chocolate for example, is slightly basic.
Bases are commonly used as household cleaning products.
Ammonia, dish soap, and detergent are all types of bases that help us clean.

11. Properties of Bases
When food or dirt is stuck to something, it is attached with trillions of hydrogen bonds. Bases have the ability to disrupt the hydrogen bonds, making the food or dirt fall of the surface of whatever you are cleaning.
Another example of this, is when we used a tiny amount of dish soap to break the hydrogen bond surface tension in liquid water causing the paperclip to sink.

12. Identifying acids and bases
HCl, H2SO4, HBr, H3PO4, HF
These are all acids, what is similar about all of these compounds?
If a chemical formula has a Hydrogen as the first element, it can usually be considered an acid.

13. Identifying acids and bases
NaOH, Ba(OH)2, LiOH, KOH
What is similar about these compounds?
Bases can be identified because they have a hydroxide group (OH) at the end.

14. Strong Acids
The definition Strong Acid means that every molecule of acid will donate the proton if it is mixed into solution.
Strong acids are 100% dissociated
in water.

15. Strong Acids The only strong acids are HI – Hydroiodic Acid
HBr - Hydrobromic Acid
HCl - Hydrochloric Acid
H2SO4 - Sulfuric Acid
HNO3 – Nitric Acid
These acids are all extremely dangerous, even at low concentrations.

16. Strong Bases
The definition Strong Base means that every molecule of base will accept a proton if it is mixed into solution.
Strong bases are 100% dissociated in water.
All strong bases contain OH in their molecules.

17. Weak Bases Only partially ionized
May or may not contain OH in their molecules.
Al(OH)3 is a weak base.
Ammonia, NH3, is also a weak base, but does not contain
OH.

18. Strong Bases The only strong bases are
NaOH - Sodium Hydroxide
KOH - Potassium Hydroxide
Ca(OH)2 - Calcium Hydroxide
Ba(OH)2 - Barium hydroxide
All of these bases are very dangerous, even at low concentrations.

19. Mixing acids with water
When an acid is mixed with water, the proton is donated and a hydronium ion is formed in water.
HCl + H2O è H3O+ + Cl-

20. Mixing acids with water
Conjugate Acid - The conjugate acid is the chemical on the product side that receives the donated proton.
HCl + H2O -> H3O+ + Cl-
The H3O+, the hydronium ion, is the conjugate acid.

21. Mixing acids with water
Conjugate Base- The conjugate base is the chemical on the product side that gave the proton away.
HCl + H2O -> H3O+ + Cl-
The Cl- is the conjugate base.

22. Mixing bases with water
When a base is mixed with water, the water donates protons to the base, forming more water, but leaving the hydroxide ion behind.
NaOH + H2O è Na+ + OH- + H2O

23. Mixing bases with water
NaOH + H2O è Na+ + H2O + OH-
NaOH is the base, and in this case, the water acts as an acid, donating a proton.
What is the conjugate acid in this case?
What is the conjugate base in this case?

24. Water as a amphoteric molecule
Amphoteric – Molecules that are relatively neutral on the pH scale, like water, have the ability to either act as a acid or base, depending on what they are mixed with.
If you mix water with an acid, the water will act as a base.
If you mix water with a base, the water will act as an acid.

25. Characteristics of Acids & Bases
Produce H3O+1 (hydronium ion) in water
Produce OH-1 (hydroxide ion) in water
Tastes sour
Tastes Bitter
React with active metals to form hydrogen gas
Feels slippery

26. Strength versus Concentration

27. Strong versus Weak Acids
How many hydronium ion – anion pairs can you find? - + - 3 +
How many intact acid molecules can you find? + - 1
Strong acid
Most of the acid molecules have donated the H+1 to water

28. Strong versus Weak Acids+
How many hydronium ion – anion pairs can you find? 1
How many intact acid molecules can you find? - 3
Weak acid
Only a few of the acid molecules have donated the H+1 to water

29. Concentrated versus Dilute
solvent
solute
Lower concentration
Not as many solute (what’s being dissolved) particles
Higher concentration
More solute (what’s being dissolved) particles

30. Combinations of Concentration & Strength
Concentrated
Dilute
Strong
A lot of acid added & most dissociates
Not much acid added, but most of what is there dissociates
Weak
A lot of acid added, but most stays together
Not much acid added and most of what is there stays together

31. pH

32. pH scale
pH is a measure of the concentration of protons in solution. This gives us a relative scale of how acidic the solution is.
At home, you use pH indicators to check your pool, hot tub, and fish tanks, to make sure that the water is at the appropriate pH.

33. pH Scale Is a scale to measure the acidity of a sample 1 14 7
Highly acidic
Very basic (not acidic)
neutral 7
A solution with a pH less than 7 indicates that the solution is acidic.
Water is right in the middle with a pH of 7. Water is considered the neutral mark when it comes to the acid/base scale.
A solution with a pH of greater than 7 is considered basic.

34. pH is a Logarithmic Scale
Logarithm –The number of times a base must be multiplied by itself to reach a given number
# of multiples
Base
# you’re trying to reach

35. Calculating pH
pH scale – Logarithmic scale of the acidity of a solution
The pH scale uses base “10”
[ ] = concentration in Molarity
pH has no units

36. The “-” in the pH equation
Because pH is the negative log of concentration of hydronium, as concentration increases, the pH goes down.
The lowest pH is the highest concentration of hydronium

37. What does a “log” scale really mean?
Every change of 1 in pH shows a change of 10x in concentration of hydronium pH 4 3 2 1
Level of acidity increases
1000x more acidic
100x more acidic
10x more acidic

38. An example of calculating pH
Find the pH if the concentration of [H3O+1] is 0.25 M

39. An example of calculating pH
Find the pH if the concentration of [H3O+1] is 0.25 M
pH = 0.60

40. An example of calculating hydronium ion concentration
Find the [H3O+1] if the pH is 2.7

41. An example of calculating hydronium
Find the [H3O+1] if the pH is 2.7
H3O+1 = M

42. Ways to measure pH Indicators change color based on pH
Liquid indicators – various indicators change colors at different pH’s (phenolphthalein, methyl red)
Universal indicator – a combination of liquid indicators to produce a “rainbow” changing colors at several pH’s
Paper Indicators
Paper with a liquid indicator on it
(Litmus paper or pH paper)
pH meters or pH probes
Electronically determine pH and give a read-out

43. Common pH indicators
This picture © 1998 David Dice

44. pH of common substances
0.1M HCl 1
Stomach contents 2
Vinegar
2.9
Soda pop 3
Grapes 4
Beer
4.5
Pumpkin pulp 5
Bread
5.5
Intestinal contents
6.5
Milk
Urine
6.6
Bile
6.9
Saliva 7
Blood
7.4
Eggs
7.8
0.1M NH3 (aq)
11.1
0.1M NaOH 13

45. pH
These are the pH values for several common substances.

46. Section 2.4—Defining, Naming & Writing Acids & Bases
We need to know what acids we’re talking about when talking about ant-acids!

47. Naming non-oxygen Acids
These compounds:
Start with “H” (more than 1 “H” is OK, too).
Do not contain oxygen
To name these compounds:
Use “hydro____ic acid”
Fill in the blank with the anion’s name without the last syllable

48. Example #1
HBr

49. HBr Example #1 Hydrobromic acid Hydrogen cation Bromine It’s an acid
No oxygen
Use “hydro___ic”

50. Naming Oxygen Acids These compounds: To name these compounds:
Start with “H” (more than 1 “H” is OK, too).
Do contain oxygen
To name these compounds:
Use “___ic acids” for “-ate” anions
Use “___ous acids” for “-ite” anions
Do not use “hydro” with these…the word “acid” is how you know it begins with hydrogen, not “hydro-”

51. Example #2
H2SO3

52. H2SO3 Example #2 Sulfurous acid Hydrogen cation Sulfite ion
It’s an acid
Hydrogen cation
H2SO3
Sulfite ion
“-ite” ion
Use “___ous” acid
Sulfurous acid

53. Example #3
H2SO4

54. H2SO4 Example #3 Sulfuric acid Hydrogen cation Sulfate ion
It’s an acid
Hydrogen cation
H2SO4
Sulfate ion
“-ate” ion
Use “___ic”
Sulfuric acid

55. Write the name for the following compounds
Let’s Practice
HCl
HNO3
H2S
H3PO3
Example:
Write the name for the following compounds

56. Write the name for the following compounds
Let’s Practice
HCl
HNO3
H2S
H3PO3
Hydrochloric acid
Nitric acid
(Hydrosulfuric acid)
Hydrogen sulfide
Phosphorous acid
Example:
Write the name for the following compounds

57. Writing Acid Formulas

58. “Hydro-” acids To write these formulas: The cation is H+1
Write the anion and charge
Balance the charges by adding the appropriate subscript to the hydrogen cation

59. Example #4
Hydrofluoric acid

60. Does not contain oxygen
Example #4
H+1
Hydrogen cation
Hydrofluoric acid
Does not contain oxygen
F-1

61. Does not contain oxygen
Example #4
H+1
Hydrogen cation
Hydrofluoric acid
Does not contain oxygen
H+1F-1
F-1
= 0 HF
The compound is neutral.
Subscripts are not needed

62. NON “Hydro-” acids Acids with Polyatomic Ions
To write these formulas:
The cation is H+1
If it is an “-ic” acid, the anion is the “-ate” polyatomic ion
If it is an “-ous” acid, the anion is the “-ite” polyatomic ion
Add subscript to the hydrogen cation to balance charges

63. Example #5
Carbonic acid

64. From the “___ate” anion
Example #5
H+1
Hydrogen cation
Carbonic acid
From the “___ate” anion
CO3-2

65. From the “___ate” anion
Example #5
H+1
Hydrogen cation
H+CO32-
= -1
Carbonic acid
H+H+CO32-
= 0
From the “___ate” anion
CO3-2
H2CO3

66. Example #6
Nitrous acid

67. From the “___ite” anion
Example #6
H+1
Hydrogen cation
Nitrous acid
From the “___ite” anion
NO3-1

68. From the “___ite” anion
Example #6
H+1
Hydrogen cation
Nitrous acid
H+NO2-
From the “___ite” anion
= 0
NO3-1
HNO2

69. Write the formula for the following acids
Let’s Practice
Phosphoric acid
Hydroiodic acid
Carbonous acid
Perchloric acid
Example:
Write the formula for the following acids

70. Write the formula for the following acids
Let’s Practice
Phosphoric acid
Hydroiodic acid
Carbonous acid
Perchloric acid
H3PO4 HI
H2CO2
HClO4
Example:
Write the formula for the following acids

71. Naming & Writing Bases

72. Naming Bases
Most bases are just ionic compounds with “hydroxide” as their anion
The most common exception to this is ammonia
NH3 (ammonia) is a base even though it doesn’t contain “-OH” as the anion

73. Example #7
NaOH

74. Example #7
Sodium
NaOH
Sodium Hydroxide
Hydroxide

75. Write the formula or name for each
Let’s Practice
Ca(OH)2
KOH
Sr(OH)2
Copper (II) hydroxide
Magnesium hydroxide
Example:
Write the formula or name for each

76. Write the formula or name for each
Let’s Practice
Ca(OH)2
KOH
Sr(OH)2
Copper (II) hydroxide
Magnesium hydroxide
Calcium hydroxide
Potassium hydroxide
Strontium hydroxide
Cu(OH)2
Mg(OH)2
Example:
Write the formula or name for each