1. Launch: 1/25
 Grab your binder and immediately take a seat!
 Place launch paper and Friday’s practice questions on
your desk.
 Friday’s Quiz Data:
94%!
 Today’s Objective: I can use the pH scale to characterize
acid and base solutions.

2. Launch: 1/25
 Grab your binder and immediately take a seat!
 Place launch paper and Friday’s practice questions on
your desk.
 Friday’s Quiz Data:
89%!
 Today’s Objective: I can use the pH scale to characterize
acid and base solutions.

3. Launch: 1/25
 Grab your binder and immediately take a seat!
 Place launch paper and Friday’s practice questions on
your desk.
 Friday’s Quiz Data:
95%!
 Today’s Objective: I can use the pH scale to characterize
acid and base solutions.

4. Launch: 1/25
 Grab your binder and immediately take a seat!
 Place launch paper and Friday’s practice questions on
your desk.
 Friday’s Quiz Data:
94%!
 Today’s Objective: I can use the pH scale to characterize
acid and base solutions.

5. Launch 1/25
1. Draw a picture of
• HCl (a strong acid) dissolved in water
• HF (a weak acid) dissolved in water

6. Launch 1/25
2. In a complete sentence, describe the difference
between strong and weak acids. (Hint: use the
word “dissociation”)

7. Launch 1/25
3. In the equation, HSO4- + H2O  H2SO4 + OH-,
which reactant molecule acts as the base?
a. HSO4-
b. H2O
c. H2SO4
d. OH-

8. Announcements
 Unit #6 Exam this Thursday!
 Ask questions
 Work with purpose
 Class rules I am focusing on this week:
 interfering with your own or someone else’s learning
 leaving seat without permission

9. January Calendar
Exam

10. What is pH?
Mr. Heffner
1/25/10

11. Review: What are strong
acids/bases?
 strong acid + strong base = water + a salt
 neutralize each other (pH 7)
an ionic
compound
HI + KOH  ?
H+ + l- + K+ + OH-  ? 2O + KI
H
a salt
water

12. What is pH?
 pH is…
 the concentration of H+ ions in a solution
pH = - log( H+ )
the molarity
function on H+ ions
of
a calculator
(mol/L)

13. What is pH?
 The pH scale is not linear
 it is logarithmic
pH = - log( H+ )
 Meaning…
 1 pH unit = 10 times the acidity
stomach acid (pH 1)
is 10X more acidic than
lemon juice (pH 2)

14. What is pH?
 For each 1 pH unit difference, add a “0”
stomach acid (pH 1)
is 10X more acidic than
1000X more acidic than
100X more acidic than
lemon soda (pH 3)
vinegar (pH 2)
juice 4)
Three“0”s b/c pH
Two “0”s b/c pH
difference = 2
difference = 3
 This is because the pH scale is logarithmic!

15. Whiteboards
 Work in pairs
 Trade-off marker every question
 Partner without the marker should be checking
work at each step!
 You have 60 seconds to answer the question
 Which is more more acidic/basic?
 How much more acidic/basic?
 Lift board only when prompted

16. Lemon juice (pH 2)
Soda (pH 4)
Which is more acidic and by how much?

17. Ammonia (pH 10)
Water (pH 7)
Which is more basic and by how much?

18. Rainwater (pH 5)
10M HCl (pH 0)
Which is the stronger acid and by how much?

19. Bleach (pH 12)
Baking soda (pH 9)
Which is the stronger base and by how much?

20. Tomato
Lemon
Which is the stronger acid and by how much?

21. Banana
Soap
Which is the stronger base and by how much?

22. Rainwater
Pure water
Which is the stronger
acid and by how much?

23. Drain cleaner
Egg whites
Which is the stronger
base and by how much?

24. Practice Questions
 Practice question worksheet

25. Binder
 Re-label your tabs:
1. Launches
2. Notes
3. Practice Questions
4. Handouts/Labs
5. Grades

26. Exit Slip
1. pH is a measure of
a. the taste of an acid or a base.
b. the ability of a solute to dissolve in solution.
c. the concentration of H+ ions in solution.
d. the strength of an ion in solution.

27. Exit Slip
2. The pH scale is
a. logarithmic, meaning that 1 pH unit equals ten times
the acidity/basicity
b. logarithmic, meaning that 1 pH unit equals one
times the acidity/basicity
c. linear, meaning that 1 pH unit equals ten times the
acidity/basicity
d. linear, meaning that 1 pH unit equals one times the
acidity/basicity

28. Exit Slip
3. Of the four different laboratory solutions below,
the solution with the highest acidity has a pH of
a. 11.
b. 7.
c. 5.
d. 3.

29. Exit Slip
4. How many times more basic is drain cleaner (pH
12) than baking soda (pH 9)?
a. 3
b. 30
c. 100
d. 1000

30. Exit Slip
5. How many times more
acidic is stomach acid than
rainwater?
a. 4
b. 10000
c. 40000
d. 100000

31. Homework
 Finish practice questions