1. power of hydrogen

3. pH scale logarithmic scale expresses H +1 concentration, [H +1 ] pH = -log[H +1 ]pH = -log[H +1 ] If pH changes by factor of 1, [H +1 ] changes by factor of 10

5. pOH = 14 10 7 4 0 increasing [H +1 ] increasing [OH -1 ] (pH goes down) (pH goes up) (more acidic) (more basic)

6. ACID or BASE or neutral? acids: [H +1 ]  [OH -1 ] neutral: [H +1 ]  [OH -1 ] bases: [OH -1 ]  [H +1 ]

8. water can undergo self-ionization H 2 O(l) + H 2 O(l)  H 3 O +1 (aq) + OH -1 (aq) H 3 O +1 H 3 O +1 = hydronium ion OH -1 = OH -1 = hydroxide ion OR H 2 O(l)  H +1 (aq) + OH -1 (aq) H +1 H +1 = hydrogen ion = proton H +1 & H 3 O +1 used interchangeably

9. Acid, Base, or Neutral? all H 2 O contains some H +1 and some OH -1 ions –pure H 2 O: ion concentrations very low (1 x 10 -14 M) neutral solution: [H +1 ] = [OH -1 ] -7 [H +1 ] = [OH -1 ] = 1 X 10 -7 M log[H +1 ]-7 pH = -log[H +1 ] = -(-7) = 7 acidic solution: H +1 > OH -1 basic solution: OH -1 > H +1

10. Convert Molarity to pH To determine pH: express [H +1 ] in scientific notation remember, [ ] means concentration of whatever is inside brackets log is the power of 10log is the power of 10 pH = -log[H +1 ] pH = -log[H +1 ]

11. pH [H +1 ] 1 M or 0 1X10 0 M 0.1 M or -1 1 X 10 -1 M 0.01 M or -2 1 X 10 -2 M 0.001 M or -3 1 X 10 -3 M pH 0 1 2 3

12. Relationships: pH, pOH, [H +1 ], [OH -1 ] pH = power of H refers to [H +1 ] OR [H 3 O +1 ] pOH = power of OH refers to [OH -1 ]

13. Here’s the math! product of [H +1 ] and [OH -1 ] is always 1x10 -14 M add exponents when multiply in scientific notation ex: (1 x 10 -4 M)(X) = 1 x 10 -14 M (X) = 1 x 10 -10 M sum of pH and pOH is always 14

14. pH + pOH = 14 pH = 3, pOH = pH = 7, pOH = pH = 10, pOH = pH = 9, pOH = pH = 1, pOH =1174 5 13

15. if pH = 4if pH = 4 [H +1 ] = ? pOH = ? [OH -1 ] = ?10 1 x 10 -4 M 1x10 -10 M

16. if the [OH -1 ] = 1 X 10 -3 pOH = ? pH = ? [H +1 ] = ? 3 14 – 3 = 11 1x10 -11 M 1x10 -11 M

17. i f the [H +1 ] = 1 x 10 -5 M pH = ? pOH = ? [OH - ] = ?5 14 – 5 = 9 1x10 -9 M 1x10 -9 M

18. 6 1x10 -2 1x10 -5 3 Acidic or Basic pOH[OH - ](M) pH[H + ](M) 11 1x10 -3 1x10 -11 A 5 9 1x10 -9 B 2 12 1x10 -12 A 8 1x10 -8 1x10 -6 B

19. How to safely test pH use instruments – pH meter use indicators – litmus paper or liquid indicators see if substance reacts with a metal other than Cu, Ag, or Au NEVER “ taste ”

20. pH meters

21. Indicators liquid substances that change color over narrow pH range use several indicators to narrow down pH range of substance see Table M