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Acids Lesson 8 Ionization of Water pH Calculations. The pH Scale Water ionizes to a small degree. H 2 O (l) ⇄ H + + OH - 2H 2 O (l) ⇄ H 3 O + + OH - Kw = [H + ][OH - ] = 1.0 x 10 -14 @ 25 0 C [H + ] and [OH - ] are inversely related!.
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Acids Lesson 8 Ionization of Water pH Calculations
The pH Scale Water ionizes to a small degree. H2O(l) ⇄ H+ + OH- 2H2O(l) ⇄ H3O+ + OH- Kw= [H+][OH-] = 1.0 x 10-14@ 250 C [H+] and [OH-] are inversely related!
1. Calculate the [H+] and [OH-] in 1.0 M HCl. HCl H+ + Cl- 1.0 M 1.0 M 1.0 M [H+][OH-] = 1.0 x 10-14 [1.0][OH-] = 1.0 x 10-14 [OH-] = 1.0 x 10-14 M Note that in acid solution the [H+] is large and the [OH-] is small.
2. Calculate the [H+] and [OH-] in 1.0 M Ba(OH)2. Ba(OH)2Ba2+ + 2OH- 1.0 M 1.0 M 2.0 M [H+][OH-] = 1.0 x 10-14 [H+][2.0] = 1.0 x 10-14 [H+] = 5.0 x 10-15 M In a basic solution the [OH-] is very large and the [H+] is very small!
3. Calculate the [H+] and [OH-] in H2O. H2O ⇄ H+ + OH- x x [H+][OH-] = 1.0 x 10-14 x2 = 1.0 x 10-14 [OH-] = [H+] = 1.0 x 10-7 M Note that in pure water that the [H+] and the [OH-] are equal!
4. The pH scale has three important end points. pH 0Strong Acid 1.0 M HCl 7Neutral H2O or NaCl 14Strong Base 1.0 M NaOH
A B C E D 14 7 pH 0 5. Match each letter with a formula. All are 1 M. NH3 HCl KOH HF H2O weak base D strong acid A strong base E weak acid B neutral C
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH We start the pH scale at 1.0 M HCl strong acid. 1.0 is the same as 1.0 x 100
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M Substitute in the [H+] and solve for [OH-]
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M Substitute in the [H+] and solve for [OH-] [H+][OH-] = 1.0 x 10-14
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M Substitute in the [H+] and solve for [OH-] [H+][OH-] = 1.0 x 10-14 [1][OH-] = 1.0 x 10-14
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 MSubstitute in the [H+] and solve for [OH-] [H+][OH-] = 1.0 x 10-14 [1][OH-] = 1.0 x 10-14 [OH-] = 1.0 x 10-14 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M Let's decrease the [H+] by a factor of 10 and solve for [OH-]
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M Note, this is neutral solution!
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M 1.0 x 10-8 M 1.0 x 10-6 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M 1.0 x 10-8 M 1.0 x 10-6 M 1.0 x 10-9 M 1.0 x 10-5 M 1.0 x 10-10 M 1.0 x 10-4 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M 1.0 x 10-8 M 1.0 x 10-6 M 1.0 x 10-9 M 1.0 x 10-5 M 1.0 x 10-10 M 1.0 x 10-4 M 1.0 x 10-11 M 1.0 x 10-3 M 1.0 x 10-12 M 1.0 x 10-2 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M 1.0 x 10-8 M 1.0 x 10-6 M 1.0 x 10-9 M 1.0 x 10-5 M 1.0 x 10-10 M 1.0 x 10-4 M 1.0 x 10-11 M 1.0 x 10-3 M 1.0 x 10-12 M 1.0 x 10-2 M 1.0 x 10-13 M 1.0 x 10-1 M 1.0 x 10-14 M 1.0 x 100 M Note this is the other end of the pH scale where [OH-] = 1.0 M
Notice that the [H+] scale goes from 1.0 M to 1.0 x 10-14 M going from 1.0 M strong acid to 1.0 M strong base. This means that the [H+] is changing by a factor of: 1.0 = 1.0 x 1014 1.0 x 10-14 There appears to be a need tosimplifythe scale. Why not take the powerof the hydrogenionconcentration and get a scale from 0 to -14. We could take the negativeof this and get a simple scalefrom0 to 14. This is called the pH scale.
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100 M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M 1.0 x 10-8 M 1.0 x 10-6 M 1.0 x 10-9 M 1.0 x 10-5 M 1.0 x 10-10 M 1.0 x 10-4 M 1.0 x 10-11 M 1.0 x 10-3 M 1.0 x 10-12 M 1.0 x 10-2 M 1.0 x 10-13 M 1.0 x 10-1 M 1.0 x 10-14 M 1.0 x 100 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100M 1.0 x 10-14 M 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M 1.0 x 10-8 M 1.0 x 10-6 M 1.0 x 10-9 M 1.0 x 10-5 M 1.0 x 10-10 M 1.0 x 10-4 M 1.0 x 10-11 M 1.0 x 10-3 M 1.0 x 10-12 M 1.0 x 10-2 M 1.0 x 10-13 M 1.0 x 10-1 M 1.0 x 10-14 M 1.0 x 100 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100M 1.0 x 10-14 M 0 1.0 x 10-1 M 1.0 x 10-13 M 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M 1.0 x 10-8 M 1.0 x 10-6 M 1.0 x 10-9 M 1.0 x 10-5 M 1.0 x 10-10 M 1.0 x 10-4 M 1.0 x 10-11 M 1.0 x 10-3 M 1.0 x 10-12 M 1.0 x 10-2 M 1.0 x 10-13 M 1.0 x 10-1 M 1.0 x 10-14 M 1.0 x 100 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100M 1.0 x 10-14 M 0 1.0 x 10-1 M 1.0 x 10-13 M 1 1.0 x 10-2 M 1.0 x 10-12 M 1.0 x 10-3 M 1.0 x 10-11 M 1.0 x 10-4 M 1.0 x 10-10 M 1.0 x 10-5 M 1.0 x 10-9 M 1.0 x 10-6 M 1.0 x 10-8 M 1.0 x 10-7 M 1.0 x 10-7 M 1.0 x 10-8 M 1.0 x 10-6 M 1.0 x 10-9 M 1.0 x 10-5 M 1.0 x 10-10 M 1.0 x 10-4 M 1.0 x 10-11 M 1.0 x 10-3 M 1.0 x 10-12 M 1.0 x 10-2 M 1.0 x 10-13 M 1.0 x 10-1 M 1.0 x 10-14 M 1.0 x 100 M
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100M 1.0 x 10-14 M 0 1.0 x 10-1 M 1.0 x 10-13 M 1 1.0 x 10-2 M 1.0 x 10-12 M 2 1.0 x 10-3 M 1.0 x 10-11 M 3 1.0 x 10-4 M 1.0 x 10-10 M 4 1.0 x 10-5 M 1.0 x 10-9 M 5 1.0 x 10-6 M 1.0 x 10-8 M 6 1.0 x 10-7 M 1.0 x 10-7 M 7 1.0 x 10-8 M 1.0 x 10-6 M 8 1.0 x 10-9 M 1.0 x 10-5 M 9 1.0 x 10-10 M 1.0 x 10-4 M 10 1.0 x 10-11 M 1.0 x 10-3 M 11 1.0 x 10-12 M 1.0 x 10-2 M 12 1.0 x 10-13 M 1.0 x 10-1 M 13 1.0 x 10-14 M 1.0 x 100 M 14
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100M 1.0 x 10-14 M 0 We can do the same 1.0 x 10-1 M 1.0 x 10-13 M 1 with the pOH 1.0 x 10-2 M 1.0 x 10-12 M 2 1.0 x 10-3 M 1.0 x 10-11 M 3 1.0 x 10-4 M 1.0 x 10-10 M 4 1.0 x 10-5 M 1.0 x 10-9 M 5 1.0 x 10-6 M 1.0 x 10-8 M 6 1.0 x 10-7 M 1.0 x 10-7 M 7 1.0 x 10-8 M 1.0 x 10-6 M 8 1.0 x 10-9 M 1.0 x 10-5 M 9 1.0 x 10-10 M 1.0 x 10-4 M 10 1.0 x 10-11 M 1.0 x 10-3 M 11 1.0 x 10-12 M 1.0 x 10-2 M 12 1.0 x 10-13 M 1.0 x 10-1 M 13 1.0 x 10-14 M 1.0 x 100 M 14
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100M 1.0 x 10-14 M 0 14 1.0 x 10-1 M 1.0 x 10-13 M 1 13 1.0 x 10-2 M 1.0 x 10-12 M 2 12 1.0 x 10-3 M 1.0 x 10-11 M 3 11 1.0 x 10-4 M 1.0 x 10-10 M 4 10 1.0 x 10-5 M 1.0 x 10-9 M 5 9 1.0 x 10-6 M 1.0 x 10-8 M 6 8 1.0 x 10-7 M 1.0 x 10-7 M 7 7 1.0 x 10-8 M 1.0 x 10-6 M 8 6 1.0 x 10-9 M 1.0 x 10-5 M 9 5 1.0 x 10-10 M 1.0 x 10-4 M 104 1.0 x 10-11 M 1.0 x 10-3 M 11 3 1.0 x 10-12 M 1.0 x 10-2 M 12 2 1.0 x 10-13 M 1.0 x 10-1 M 13 1 1.0 x 10-14 M 1.0 x 100 M 14 0
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pH pOH 1.0 x 100M 1.0 x 10-14 M 0 14 1.0 x 10-1 M 1.0 x 10-13 M 1 13 1.0 x 10-2 M 1.0 x 10-12 M 2 12 1.0 x 10-3 M 1.0 x 10-11 M 3 11 1.0 x 10-4 M 1.0 x 10-10 M 4 10 1.0 x 10-5 M 1.0 x 10-9 M 5 9 1.0 x 10-6 M 1.0 x 10-8 M 6 8 Note that the pH + pOH = 14 1.0 x 10-7 M 1.0 x 10-7 M 7 7 @ 250C 1.0 x 10-8 M 1.0 x 10-6 M 8 6 1.0 x 10-9 M 1.0 x 10-5 M 9 5 1.0 x 10-10 M 1.0 x 10-4 M 104 1.0 x 10-11 M 1.0 x 10-3 M 11 3 1.0 x 10-12 M 1.0 x 10-2 M 12 2 1.0 x 10-13 M 1.0 x 10-1 M 13 1 1.0 x 10-14 M 1.0 x 100 M 14 0
pH ScaleKw = [H+][OH-] = 1.0 x 10-14 [H+] [OH-] pHpOH -1 1.0 x 100M 1.0 x 10-14 M 014 1.0 x 10-1 M 1.0 x 10-13 M 113 1.0 x 10-2 M 1.0 x 10-12 M 212 1.0 x 10-3 M 1.0 x 10-11 M 311 1.0 x 10-4 M 1.0 x 10-10 M 410 1.0 x 10-5 M 1.0 x 10-9 M 59 1.0 x 10-6 M 1.0 x 10-8 M 68 Note that the the scale can go 1.0 x 10-7 M 1.0 x 10-7 M 77 to -1 and 15 1.0 x 10-8 M 1.0 x 10-6 M 86 1.0 x 10-9 M 1.0 x 10-5 M 95 1.0 x 10-10 M 1.0 x 10-4 M 104 1.0 x 10-11 M 1.0 x 10-3 M 113 1.0 x 10-12 M 1.0 x 10-2 M 122 1.0 x 10-13 M 1.0 x 10-1 M 131 1.0 x 10-14 M 1.0 x 100 M 140 15