1. Chapter 19: Acids, Bases, pH and pOH
They are everywhere..
In your food
In your house
EVEN IN YOU!!!!!

2. I Can … Explain the pH scale in terms of hydrogen ion concentration
Explain the pH scale in terms of hydroxide ion concentration
Explain the pH scale in terms of acidity
Explain the pH scale in terms of basicity

3. An acid is… An aqueous solution that has H+ ions.
The more H+ ions, the more acidic the solution.
Examples of acids: HCl (H+ and Cl-), HNO3 (H+ and NO3-)

4. Properties of an Acid Tastes Sour Corrosive
Turns blue litmus paper red
Picture from BBC Revision Bites

5. Some Common Acids Vinegar Citrus fruits (lemons, limes, & oranges
Ascorbic acid = Vitamin C which your body needs to function.
Car batteries

6. A Base is .. An aqueous solution that has OH- ions. Base = alkaline
Examples of Bases: NaOH (Na+ and OH-), Ca(OH)2 (Ca+2 and OH-)

7. Properties of Bases Feel Slippery Taste Bitter Corrosive
Turns red litmus paper blue.

8. pH Scale pH is a measure of how acidic or basic a solution is.
Ranges from 0 to 14.
Acidic solutions - pH below 7
pH of 7 is neutral.
Pure water has a pH of 7
Basic solutions - pH above 7.

9. pH Scale
A change of 1 pH unit represents a tenfold (x10) change in the acidity of the solution.
Tomato – pH 4
Lemon - pH 2
Lemons are 100 times more acidic than tomatoes

10. Acid – Base Reactions
A reaction between an acid and a base is called neutralization.
The result of a “perfect” neutralization reaction is a solution with a pH of 7

11. Acid – Base reactions
HCl NaOH  NaCl H2O
The products of an acid base reaction are a salt and water
This is a type of double replacement reaction

12. Acid Nomenclature An easy way to remember which goes with which…
No Oxygen
In acid
w/Oxygen
An easy way to remember which goes with which…
“You ATE something ICky, and you bITE something deliciOUS”

13. Examples: Memorize these four acids – names and chemical formulas
HCl hydrochloric acid
H2SO4 sulfuric
HNO3 nitric
H3PO4 phosphoric

15. For simplicity you will use 3 significant figures for pH, pOH, [H+] and [OH-] calculations

16. Calculating the pH or pOH
pH = - log [H+]
pOH = - log [OH-]
(The brackets [ ] mean concentration or Molarity)
Example: If [H+] = 1.00 X M, what is the pH? pH = - log (1 X 10-10)
pH = 10.0
Example: If [OH-] = 1.80 X 10-5 M ,what is the pOH? pOH = - log 1.80 X 10-5
pOH = 4.74

17. 2) A 0.15 M solution of hydrochloric acid (acids have H+ ion)
pH = - log [H+]
Find the pH of these:
[H+] = 1.25 x M
pH = 2.90
2) A 0.15 M solution of hydrochloric acid (acids have H+ ion)
pH = 0.824
3) A 3.00 X 10-7 M solution of nitric acid
pH = 6.52

18. 2) A 0.350 M solution of NaOH (bases have OH- ion)
pOH = - log [OH-]
Find the pOH of these:
[OH-] = 2.15 x 10-3
pOH = 2.67
2) A M solution of NaOH (bases have OH- ion)
pOH = 0.456
3) A 3.00 X 10-7 M solution of potassium hydroxide
pOH = 6.52

19. Calculating the pOH or pH when you KNow the other One
Since acids and bases are opposites, pH and pOH are opposites!
If pH = 1, then pOH = 13
Since pH and pOH are on opposite ends,
pH + pOH = 14

20. pH and pOH calculations Solving for [H+] and [OH-]
If the pH of Coke is 3.12, [H+] = ???
Because pH = - log [H+] then
[H+] = antilog-pH
[H+] = 10-pH
[H+] = = 7.59 x 10-4 M

21. pOH calculations – Solving for [OH-]
If the pOH of soap is 8.9, what is the [OH-]?
[OH-] = 10-pOH
[OH-] = =
1.26 x 10-9

22. [H+], [OH-] anD kw We can also use Kw (water constant)
Kw = 1 x 10-14
Kw = [H+] [OH-] , so
[H+] [OH-] = 1 x 10-14
What is the [H+] of a solution that
has an [OH-] = 4.20 x 10-5 ?
2.38 x 10-10

23. Chapter 19 Acids and Bases Equation sheet - use this during exam
[H+] to pH (-), then log, then number
[OH-] to pOH Same as above
pH to pOH or pOH to pH pH + pOH = 14
pH to [H+] 2nd, then log, then (-), then number
pOH to [OH-] Same as above
[H+] to [OH-] or [OH-] to [H+] [H+] [OH-] = 1.0 x 10-14

24. Examples:
What is the pH of a 1.70 x 10-5 M solution of HCl?
pH = 4.77
What is the pOH of a .0320M solution of NaOH?
pH = 1.49
3. A solution has a pH of 6.40, what is the [H+]?
3.98 x 10-7 M
What is the pOH of a solution with a pH of 4.50?
pH = 9.50

25. Is this an acid, base, or neutral?
5. What is the [H+] of a 1.6 x 10-9 M
solution of NaOH?
[OH-] = 1.6 x M
1.0 x 10-14
1.6 x = [H+] = 6.3 x 10-6 M
6. What is the [H+], [OH-], and pOH
of a solution with pH = 3.67?
pOH = 10.33
[H+] = 2.14 x 10-4 M
[OH-] = 4.68 x M
Is this an acid, base, or neutral?

26. pH testing There are several ways to test pH
Blue litmus paper (red = acid)
Red litmus paper (blue = basic)
pH paper (multi-colored)
pH meter (7 is neutral, <7 acid, >7 base)
Indicators like phenolphthalein – we will use this

27. ACID-BASE Titrations REACTIONS
HCl (aq) + NaOH (aq)  NaCl (aq) + H2O (l)
acid base
We can carry out this neutralization reaction using TITRATION.
This will allow us to determine the unknown concentration of an acid or base ([H+] or [OH-])

28. ACID-BASE REACTIONS Titrations
At the end of a titration reaction Moles of acid = moles of base

29. Titration is used to determine the Concentration of OH- (or H+) ion in
the solution being analyzed
Titration video 3:15 min

30. Titration Calculations
For titrations using HCl and NaOH, we can simply use the dilution formula to do our calculations (because there is one H+ for every one OH-)
M1V1 = M2V2

31. Titration Calculations
Example: Determine the volume of M NaOH needed to titrate 20.0mL of 0.400M HCl?

32. Titration Calculations
Example: What is the concentration of HCl if 34.5 mL of .0500M NaOH is required to titrate 50.0mL of the HCl solution?