1. Wake-up Write down each equation below. Identify the base (B), acid (A), conjugate acid (CA), and conjugate base (CB). 1.NH 3 + HCN  NH 4 + CN 1.HSO 4 + PO 4  HPO 4 + SO 4 1.HCO 2 H + OH  H 2 O + CO 2 H

2. pH and pOH Ways to measure Acidity/Basicity What is pH? What is pOH?

3. What does pH represent? Parts Hydrogen

4. pH Measurement that reveals if a solution is acidic or basic

5. What is the pH Scale? Runs from 0.0 to 14.0 with 7.0 being neutral; Logarithmic

6. pH scale 114 768 Acid Base (Alkaline) Neutral

7. Logarithmic Scale A ten-fold difference between each successive full number on the scale

8. Logarithmic Scale – ACID Each whole pH value BELOW 7 is ten times more acidic than the next higher value. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6.

9. Logarithmic Scale: BASE Each whole pH values ABOVE 7 is ten times more basic than the next lower whole value. For example, pH 10 is ten times more alkaline than pH 9 and 100 times (10 times 10) more alkaline than pH 8.

10. Basic Equations (Reference Table) pH = -log[H + ] pOH = -log[OH - ] pH + pOH = 14 [H+] = 10 -pH [OH-] = 10 -pOH

11. Example #1 What is the pH of a 0.031 M HCl solution? Known = 0.031 M HCl Unknown = pH pH = -log[H + ] pH = -log [0.031M] pH = 1.5

12. Example #2 What is the pH of a 2.50 x 10 -6 M HNO 3 solution? Known = 2.50 x 10 -6 M HNO 3 Unknown = pH pH = -log[H + ] pH = -log [2.50 x 10 -6 M] pH = 5.60

13. Example #3 What is the pH of a 0.025 M NaOH solution? Known = 0.025 M NaOH Unknown = pH pOH = -log[OH + ] pOH = -log [0.025 M] = 1.6 pOH pH = 12.4 pH + pOH = 14 pH + 1.6 = 14

14. Example #4 What is the pH of a 0.000051 M NaOH solution? Known = 0.000051 M NaOH Unknown = pH pOH = -log[OH + ] pOH = -log [0.000051 M] = 4.3 pOH pH = 9.7 pH + pOH = 14 pH + 4.3 = 14

15. Calculating pOH pOH = 14 – pH pOH = -log[OH-] EXAMPLE: What is the pOH of a solution that has a hydroxide ion concentration of 4.82 x 10 -5 M ? pOH = - log [OH - ] pOH = - log [4.82 x 10 -5 ] pOH = 4.32

16. YOU TRY! Find the pH of the solution if [H+] = 1 x 10 -4 M What is the hydrogen ion concentration if pH = 7.1? What is the pH if [OH-] = 4 x 10 -11 M? pH = 4 7.1 = -log [H + ] 10 – 7.1 = [H + ] = 7.9 x 10 -8 M pOH = -log [OH-] pOH = -log [4 x 10 -11 ] =

17. pH scale 114 768 Acid Base Strong Acid Strong Base Weak Acid Weak Base Neutral

18. Breakdown of water