1. The Chemistry of Acids and Bases

2. Acids and Bases: Calculate pH/pOH At the conclusion of our time together, you should be able to: 1. Change any pH reading to pOH 2. Convert pH to concentration of hydronium ion concentrations, hydronium ion concentrations to pH

3. Review of the pH Scale  Since 1 mole of OH - in one Liter of water would be a pOH = 0  And the pH and pOH of water is 7 or neutral,  Therefore, the pH of a strong base with a pOH of 0 would be  pH = 14  Therefore, any pH can be converted to pOH by subtracting from 14.

4. Examples of Converting pH  If an acid has a pH of 3, what would be the pOH?  14 – 3 =  11  If an base has a pOH of 2, what would be the pH?  14 – 2 =  12

5. Calculating the pH pH = - log [H+] (Remember that the [ ] mean Molarity) Example: If [H + ] = 1 X 10 -10 pH = - log 1 X 10 -10 pH = - (- 10) pH = 10 Example: If [H + ] = 1.8 X 10 -5 pH = - log 1.8 X 10 -5 pH = - (- 4.74) pH = 4.74

6. pH Calculations – Solving for H + on Worksheet #1 If the pH of Coke is 3.55, [H + ] = ??? Because pH = - log [H + ] then - pH = log [H + ] - pH = log [H + ] Take antilog/inverse log (10 x ) of both sides and get 10 -pH = [H + ] [H + ] = 10 -3.55 = 2.82 x 10 -4 M *** to find antilog/inverse on your calculator, look for “Shift” or “2 nd function” and then the log button *** to find antilog/inverse on your calculator, look for “Shift” or “2 nd function” and then the log button

7. Worksheet #2, #3  If an acid has a pH of 3.55, what would be the pOH?  14 – 3.55 =  10.45  What is the concentration of OH - ? [OH - ] = 10 -10.45 =  3.55 x 10 -11 M

8. pH Calculations – #4  A solution has a [OH - ] of 4.25 x 10 -4. pOH = - log [OH - ] pOH = - log [4.25 x 10 -4 ] pOH = 3.37 pH = 14 – 3.37 = 10.63 pOH = - log [OH - ] pOH = - log [4.25 x 10 -4 ] pOH = 3.37 pH = 14 – 3.37 = 10.63

9. pH [H + ] [OH - ] pOH

10. A Former Student Trying to Apply His Knowledge of Chemistry!!

11. [OH - ] [H + ] pOH pH 10 -pOH 10 -pH -Log[H + ] Log[OH - ] -Log[OH - ] 14 - pOH 14 - pH 1.0 x 10 -14 [OH - ] [OH - ] 1.0 x 10 -14 [H + ] [H + ]

12. Acids and Bases: Calculate pH/pOH Let’s see if you can: 1. Change any pH reading to pOH 2. Convert pH to concentration of hydronium ion concentrations, hydronium ion concentrations to pH

13. The American Medical Association announced today that the Universal Choking Sign has been revised:

14. Old Sign:

15. New Sign:

16. Calvin’s Approach to Math in Chemistry:

17. Get Your Clicker!!!

18. If a solution has a pH of 6.5, what is the pOH of that same solution? 1234567891011121314151617181920 21222324252627282930 1. 4.5 2. 7.5 3. 6.5 4. 0.0 5. 12.5

19. If a solution has a pH of 8.6, what is the [H + ] of that solution? 1234567891011121314151617181920 21222324252627282930 1. 8.6 2. 2.51 x 10 -9 3. 1.0 x 10 8.6 4. 1.0 x 10 5.4 5. 5.4

20. If a solution has a pOH of 9.44, what is the [OH - ] of that same solution? 1234567891011121314151617181920 21222324252627282930 1. 0.975 2. 1.00 x 10 9.44 3. 3.63 x 10 -10 4. 4.56 5. 9.44

21. If a solution has a [H 3 O + ] of 6.20 x 10 -8, what is the pH of that solution? 1234567891011121314151617181920 21222324252627282930 1. 6.79 2. 8.79 3. 5.21 4. 4.56 5. 7.21

22. If a solution has a [OH - ] of 1.05 x 10 -3, what is the pH of that solution? 1234567891011121314151617181920 21222324252627282930 1. 11.02 2. 2.98 3. 1.00 4. 3.02 5. 10.98

24. Acid Base Calculation Practice #1  pH = 12.40, what would be the pOH?  14 – 12.40 =  1.60  What is the concentration of OH - ? [OH - ] = 10 -1.60 =  0 0251 M

25. Acid Base Calculation Practice #2  pOH? of 0.00162 M KOH  pOH = - log 0.00162  = 2.79  pH = 14 – 2.79 =  11.21

26. Converting pH to pOH  If an acid has a pH of 6, what would be the pOH?  14 – 6 = 8888

27. [H 3 O + ], [OH - ] and pH What is the pH of the 0.0010 M NaOH solution? [OH - ] = 0.0010 (or 1.0 X 10 -3 M) pOH = - log 0.0010 pOH = - log 0.0010 pOH = 3 pOH = 3 pH = 14 – 3 = 11 pH = 14 – 3 = 11

28. The pH of rainwater collected in a certain region of the northeastern United States on a particular day was 4.82. What is the H + ion concentration of the rainwater? The OH - ion concentration of a blood sample is 2.5 x 10 -7 M. What is the pH of the blood? Try These! 1.51 x 10 -5 pOH = 6.6 14.0 – 6.6 = 7.4 pH

29. Calculating [H 3 O + ], pH, [OH - ], and pOH Problem 1: A chemist dilutes concentrated hydrochloric acid to make two solutions: (a) 3.0 M and (b) 0.0024 M. Calculate the [H 3 O + ], pH, [OH - ], and pOH of the two solutions at 25°C. [H 3 O + ] = 3.0 M pH = -0.47 [OH - ] = 3.388 x 10 -15 M pOH = 14.47 [H 3 O + ] = 0.0024 M pH = 2.6 [OH - ] = 3.98 x 10 -12 M pOH = 11.4

30. Calculating [H 3 O + ], pH, [OH - ], and pOH Problem 2: What is the [H 3 O + ], [OH - ], and pOH of a solution with pH = 3.67? Is this an acid, base, or neutral? [H 3 O + ] = 2.14 x 10 -4 M pH = 3.67 [OH - ] = 4.677 x 10 -11 M pOH = 10.33