1. Acids and Bases

2. Properties of Acids and Bases
Tart or sour taste (think of lemons)
DO NOT TASTE CHEMICALS!
Corrosive to metals
React with bases to form a salt and water
On the pH scale: acids have a pH less than 7
Litmus paper = RED
BASES
Bitter taste (think of baking soda)
DO NOT TASTE CHEMICALS!
Corrosive to organic materials
React with acids to form a salt and water
On the pH scale: bases have a pH greater than 7
Litmus paper = BLUE
Feel slippery
Breaking Bad:
Fight Club:

4. Acids
Arrhenius Definition: Break apart (dissociate) to yield hydrogen ions (H+) in water (aqueous) solutions
HCl H+ + Cl-
HNO H+ + NO3-
H2SO H+ + HSO4 -
H2O
H2O
H2O

5. Naming Acids HCl H2SO3 HNO3 chloride hydro-(stem)-ic acid
Anion Ending
Anion Example
Acid Name
Example
-ide
-ite
-ate
chloride
hydro-(stem)-ic acid
hydrochloric acid
HCl
sulfite
(stem)-ous acid
sulfurous acid
H2SO3
nitrate
(stem)-ic acid
nitric acid
HNO3

6. Naming Acids Name the following acids: H2CrO4 HF H2CO3 HClO2 CH3COOH
Anion Ending
Acid Name
-ide
hydro-(stem)-ic acid
-ite
(stem)-ous acid
-ate
(stem)-ic acid

7. Writing Formulas of Acids
Write the formulas for the following acids:
Phosphorous acid
Anion Ending
Acid Name
-ide
hydro-(stem)-ic acid
-ite
(stem)-ous acid
-ate
(stem)-ic acid

8. Bases
Arrhenius Definition: Break apart (dissociate) to yield hydroxide ions (OH-) in water (aqueous) solutions
NaOH Na+ + OH-
KOH K+ + OH-
H2O
H2O

9. Naming Bases Cation name + hydroxide NaOH sodium hydroxide Ca(OH)2
calcium hydroxide
NH4OH
ammonium hydroxide
Cation name + hydroxide

10. Naming Bases Name the following bases: Ba(OH)2 KOH Al(OH)3
Cation name + hydroxide

11. More Naming Practice H3PO4 Nitrous acid Mg(OH)2 Hydrobromic acid
Name the following acids/bases or write their formula:
H3PO4
Nitrous acid
Mg(OH)2
Hydrobromic acid
Lithium hydroxide
H2S
Anion Ending
Acid Name
-ide
hydro-(stem)-ic acid
-ite
(stem)-ous acid
-ate
(stem)-ic acid

12. Even More Naming Practice!
Identify whether the following are acids or bases. Then name them!
Ba(OH)2
2. H2S
3. CH3COOH
4. Fe(OH)2
5. HClO2
Anion Ending
Acid Name
-ide
hydro-(stem)-ic acid
-ite
(stem)-ous acid
-ate
(stem)-ic acid

13. The pH Scale

14. Remember the household products lab?
You tested household chemicals with litmus paper and pH paper.
Product
Color pH
Formula
Acid/Base? 1. 2. … 9.

15. What happened to the pH paper?
pH paper (aka Universal Indicator Paper)
What color(s) do/does the paper turn for acids?
What color(s) do/does the paper turn for bases?
Reds and oranges
Greens and Blues

16. What is the pH scale? pH: stands for “potential of hydrogen”
represents the hydrogen ion (H+) concentration of a solution

17. The pH scale Acidic solution: pH < 7.0 Neutral solution: pH = 7.0
Basic solution: pH > 7.0
Neutral
ACIDIC
BASIC
pH =
Increasing acidity
Increasing basicity

18. The pH Scale

19. The pH Scale

20. How can you tell the pH of a chemical?
Use an indicator!
Indicator paper (like pH paper)
Liquid indicators (like phenolphthalein)
pH meters

21. The pH range varies for different indicators
Indicator: a chemical or solution that changes color at a certain pH
The pH range varies for different indicators

22. LAB: Fruit and Vegetable Indicators
Purpose:
Many naturally colored compounds can behave as acid-base indicators. In this lab, you will be given a choice of several different fruits and vegetables. Your goal is to make indicators from these fruits and vegetables.
Your goal today:
- With your group, write a DETAILED procedure for how you will prepare your three fruit and vegetable indicator solutions.
- Get approved by me before the end of the hour.

23. Indicator Lab Instructions:
Many naturally colored compounds can behave as acid-base indicators. In this lab, you will be given a choice of several different fruits and vegetables. Your goal is to make indicators from these fruits and vegetables.
On lined notebook paper, you must do the following:
Write a purpose.
Provide a complete set of instructions for making the indicator solution from the raw materials and testing the solution. (The indicator is usually in the skin of the fruit or veggie. You will have to boil the fruit or veggie in a small amount of water to extract the indicator).
Create a data table listing your results for 3 indicator solutions (see below).
Answer the analysis questions.
Available Materials: solutions with various pH, carrots, blueberries, red cabbage, red grapes, red onions, tea leaves, 100mL beaker, deionized water, pipettes, well plates, scoopula

24. DEMO
Why do chemistry teachers like to teach about hydroxides?

25. Calculating pH and pOH

26. Acids
Recall that acids dissociate in water and give off H+ ions
HCl H+1 + Cl-1
H2O

27. [H+] = the hydrogen ion concentration IN MOLARITYpH
What is an easy way of representing the concentration of hydrogen ions in a solution?
pH (“potential of hydrogen”): a way of expressing the hydrogen ion concentration
pH = - log [H+]
[H+] = the hydrogen ion concentration IN MOLARITY

28. Calculating pH [H+] pH 1 1 x 10-3 M 2 1 x 10-5 M 3 1 x 10-7 M 4
Calculate the pH values using the equation pH = - log [H+]. Do you notice a pattern?
3.0
5.0
7.0
9.0
12.0
As the pH value increases, the H+ concentration decreases

29. The pH Scale As the pH value increases, the H+ concentration decreases
As the pH value decreases, the H+ concentration increases

30. Calculating pH Example
pH = - log [H+]
What is the pH of a HCl solution in which [H+] = 3.9 x 10-4 M?

31. [H+] = the hydrogen ion concentration IN MOLARITY
Calculating [H+]
How do we calculate the hydrogen ion concentration, [H+], if we know the pH?
[H+] = 10-pH
pH = - log [H+]
[H+] = the hydrogen ion concentration IN MOLARITY

32. Calculating [H+] Example
[H+] = 10-pH
What is the [H+] of a solution if the pH = 10.8?

33. Bases
Recall that bases dissociate in water and give off OH-1 ions
NaOH Na+1 + OH-1
H2O

34. [OH-] = the hydroxide ion concentration IN MOLARITY
pOH
Just like with pH…
pOH (“potential of hydroxide”): a way of expressing the hydroxide ion concentration (the OH-)
pOH = - log [OH-]
[OH-] = the hydroxide ion concentration IN MOLARITY
Just like with [H+]:
[OH-] = 10-pOH
The only way to go between H and OH:
pH + pOH = 14

35. Example #1
What is the pOH of a solution if the [OH-] = 3.5 x 10-9 M?

36. Example #2
What is the pH of a solution if the [OH-] = M?

37. Example #3
What is the hydrogen ion concentration of a solution if the pOH is equal to 11.2?

38. Acid-Base Neutralization Reactions

39. Neutralization Reactions
Remember double replacement reactions?
HCl + NaOH → ____ + ____
To write balanced reaction:
1. Circle any polyatomic ions
2. Label charges
3. Write products – make charges cancel!
4. Balance using coefficients

40. Neutralization Reactions
Remember double replacement reactions?
HCl + NaOH → ____ + ____
HCl + NaOH → NaCl + HOH
All neutralization reactions will have this format…
Acid + Base  Salt + water (H2O)

41. Neutralization Reactions Practice #1
Name the acid and the base:
HCl + Ca(OH)2 
hydrochloric acid
calcium hydroxide
Complete and balance the neutralization reaction:
HCl + Ca(OH)2  _____ + _____
2HCl + Ca(OH)2  CaCl H2O
Remember:
1. Circle any polyatomic ions
2. Label charges
3. Write products – make charges cancel!
4. Balance using coefficients

42. Neutralization Reactions Practice #2
Name the acid and the base:
H2SO4 + NaOH 
sulfuric acid
sodium hydroxide
Complete and balance the neutralization reaction:
H2SO4 + NaOH  _____ + _____
H2SO4 + 2NaOH  Na2SO H2O
Remember:
1. Circle any polyatomic ions
2. Label charges
3. Write products – make charges cancel!
4. Balance using coefficients

43. Neutralization Reactions Practice #3
Name the acid and the base:
H2SO3 + NH4OH 
sulfurous acid
ammonium hydroxide
Complete and balance the neutralization reaction:
H2SO3 + NH4OH  _____ + _____
H2SO NH4OH  (NH4)2SO H2O
Remember:
1. Circle any polyatomic ions
2. Label charges
3. Write products – make charges cancel!
4. Balance using coefficients

44. Neutralization Practice

45. Neutralization Reactions Practice #4
Name the acid and the base:
H3PO4 + LiOH 
phosphoric acid
lithium hydroxide
Complete and balance the neutralization reaction:
H3PO4 + LiOH  _____ + _____
H3PO4 + 3LiOH  Li3PO H2O
Remember:
1. Circle any polyatomic ions
2. Label charges
3. Write products – make charges cancel!
4. Balance using coefficients

46. Acid-Base Titrations

47. Titrations
Titration: adding a known amount of solution of known concentration to a solution with an unknown concentration
Goal: To determine the unknown concentration of a solution

48. Titrations Endpoint: the point of neutralization in a titration
How do we know we reached the endpoint in a titration? We use an indicator and look for a color change!

49. To solve this problem, we need to use the box method!
Titration Example
A 2.5 L solution of H2SO4 is completely neutralized by 0.5 L of 1.0 M NaOH. What is the concentration of the H2SO4 solution?
In buret:
1.0 M NaOH
To solve this problem, we need to use the box method!
In Erlenmeyer flask:
? M H2SO4

50. A 2. 5 L solution of H2SO4 is completely neutralized by 0. 5 L of 1
A 2.5 L solution of H2SO4 is completely neutralized by 0.5 L of 1.0 M NaOH. What is the concentration of the H2SO4 solution?
Step 1: Write the balanced neutralization equation.
H2SO4 + 2 NaOH  Na2SO4 + 2 H2O

51. H2SO4 + 2 NaOH  Na2SO4 + 2 H2O 0.25 mol 0.5 mol 0.10 M 1.0 M 2.5 L
A 2.5 L solution of H2SO4 is completely neutralized by 0.5 L of 1.0 M NaOH. What is the concentration of the H2SO4 solution?
Step 2: Draw the box, fill in known information, and calculate missing information.
H2SO4 + 2 NaOH  Na2SO4 + 2 H2O
x 1/2
Multiply by molar ratio
Moles (mol)
Molarity (M)
Liters (L)
0.25 mol
0.5 mol
0.10 M
1.0 M
Moving up = multiply
2.5 L
0.5 L
Moving down = divide

52. Titration Practice - #1 on WS
30 mL of 0.10 M NaOH is used to completely neutralize 25.0 mL of HCl. Determine the concentration of the acid.
Moles (mol)
Molarity (M)
Liters (L)

53. HCl Titration Lab – Analysis Questions
Work with your partner to complete questions 3-5 on your lab…

54. Titration Practice #1
A 1.5 L solution of HCl is completely neutralized by 2.0 L of 0.5 M Al(OH)3. What is the concentration of the HCl solution?
Moles (mol)
Molarity (M)
Liters (L)

55. Titration Practice #2
A 25 mL solution of H2SO4 is completely neutralized by mL of 1.0 M NaOH. What is the concentration of the H2SO4 solution?
Moles (mol)
Molarity (M)
Liters (L)