1. power of hydrogen

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

5. 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 10

6. Molarity to pH for Pure water
tiny bit of ionization in pure water:
H2O  H+1 + OH-1
[H+1] = [OH-1] = 1 X 10-7 M
pH = -log[H+1] = -(-7) = 7

7. pH 3 2 1 pH
.001 M or
1 X M
0.01 M
1 X M
0.1 M
1 X M
1 M
1X100 M
[H+1]

9. pOH =

10. pH range
0 to (7 is neutral)
pH = 0, strongly acidic
pH = 14, strongly basic

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

13. Relationships of: pH, pOH, [H+1] and [OH-1]
product of [H+1] and [OH-1] is always 1x10-1M
add exponents when multiple in scientific notation
sum of pH and pOH is always 14

14. pH + pOH = 14 pH = 3, pOH = 11 pH = 7, pOH = pH = 10, pOH = 75 13

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

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

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

18. 6
1x10-2
1x10-5 3
Acidic or
Basic
pOH
[OH-]
(M) pH
[H+]
1x10-3
1x10-11 11 A 9 B
1x10-9 5 A 2
1x10-12 12
1x10-8 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. Indicator (l) substance that changes color over narrow pH range
use several indicators to narrow down pH range of substance
See Table M