Transcript AP Chemistry pH Loop

AP Chemistry pH Loop
Wednesday, April 18, 2012
pH Loop
[H+]
[H+] = 10-pH
pH
pH = - log [H+]
[H+]
[OH-]
=
pH + pOH = 14.00
10-14
[OH-]
[OH-] = 10-pOH
pOH
pOH = - log [OH-]
April 28, 2020
2
Using the loop, calculate the pOH, [H+], and
[OH-] in any order if the pH of a solution is 3.
• Clockwise
• pOH = 14 – 3 = 11
• Counterclockwise
• pH = 3, [H+] = 10-3 M
• [OH-] = 10-11 M
• [OH-] = 10-14 = 10-11 M
10-3
• [OH-] = 10-11, pOH = 11
• [H+] = 10-14 = 10-3M
10-11
• [H+] = 10-3 M, pH = 3
April 28, 2020
• pH = 14 – 11 = 3
3
[H+]
[OH-]
pH
pOH
acidic
or
basic?
6
5
0.1 M
10-1 M
10-2 M
4
10-9
April 28, 2020
4
[H+]
[OH-]
pH
pOH
1x10-8
1x10-5
0.1 M
1x10-13
1x10-12
1x10-10
10-9
1x10-6
1x10-9
1x10-13
10-1 M
10-2 M
1x10-4
1x10-5
8
5
1
13
12
10
9
6
9
13
1
2
4
5
April 28, 2020
acidic
or
basic?
Basic
Acidic
Acidic
Basic
Basic
Basic
Basic
5
Calculator tutorial for logs and antilogs
• Calculate the pH of a solution if
•
[H+] = 2.7 x 10-4 M.
• pH = - log(2.7 x 10-4)
– Press
– (-) log(2.7 2nd EE (-) 4
– 3.56
April 28, 2020
6
The pOH of a solution is 6.24. Find
[OH-]
• pOH = 10-6.24
• 2nd (10x) -6.24
• = 5.75 x 10-7 M
April 28, 2020
7
• [OH-] = 5.2 x 10-9 M. Calculate pOH, pH, and
[H+], using the pH loop.
April 28, 2020
8
Solution
• pOH = - log (5.2 x 10-9) = 8.28
• pH = 14.00 – 8.28 = 5.72
• [H+] = 10-5.72 = 2nd (10x) (-5.72)
• = 1.9 x 10-6 M
• [OH-] = 1.0 x 10-14 = 5.2 x 10-9 M
1.9 x 10-6
April 28, 2020
9
[H+]
[OH-]
pH
pOH
acidic or
basic?
6.62
2.5 x 10-10
M
1.1 x 10-11
M
4.06
5.54
2.8 x 10-1
M
7.2 x 10-2
M
7.40
April 28, 2020
10
[H+]
[OH-]
2.4x10-7 4.2x10-8
4.0x10-5 2.5 x 10-10
M
9.1x10-4 1.1 x 10-11
M
8.7x10-5 1.1x10-10
3.5x10-9 2.9x10-6
2.8 x 10-1 3.5x10-14
M
7.2 x 10-2 1.4x10-13
M
2.5x10-7 4.0x10-8
April 28, 2020
pH
pOH
acidic or
basic?
Acidic
Acidic
6.62
4.4
7.38
9.60
3.04
10.96 Acidic
4.06
8.46
0.55
9.94 Acidic
5.54 Basic
13.45 Acidic
1.14
12.86 Acidic
6.60
7.40
Acidic
11