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Acids & Bases. Calculating pH and Naming. Finding the pH of Solutions. Self- ionization of water – the simple dissociation of water H 2 O H + + OH - Concentration of ea. ion in pure water: [H + ] = 1.0 x 10 -7 M + [OH - ] = 1.0 x 10 -7 M - PowerPoint PPT Presentation
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Acids Acids & &
BasesBasesCalculating pH and Calculating pH and
NamingNaming
Finding the pH of SolutionsSelf- ionization of water – the simple dissociation of water
H2O H+ + OH-
Concentration of ea. ion in pure water: [H+] = 1.0 x 10-7M + [OH-] = 1.0 x 10-7M
Ion-product constant for water (Kw), Where KWhere Kww = 1.0 x 10 = 1.0 x 10-14-14
KKww = [H = [H++] [OH] [OH--]]
Acid [H+] > [OH-] Base [H+] < [OH-]
Neutral [H+] = [OH-]
pH Scale
pH = -log[H+]
pOH = -log[OH-]
pH + pOH = 14
[OH-] pOH pH [H+]
1 x 10-14 14 0 1 x 100
1 x 10-13 13 1 1 x 10-1
1 x 10-12 12 2 1 x 10-2
1 x 10-11 11 3 1 x 10-3
1 x 10-10 10 Increasing acidity 4 1 x 10-4
1 x 10-9 9 5 1 x 10-5
1 x 10-8 8 6 1 x 10-6
1 x 10-7 7 Neutral 7 1 x 10-7
1 x 10-6 6 8 1 x 10-8
1 x 10-5 5 9 1 x 10-9
1 x 10-4 4 Increasing basicity 10 1 x 10-10
1 x 10-3 3 11 1 x 10-11
1 x 10-2 2 12 1 x 10-12
1 x 10-1 1 13 1 x 10-13
1 x 100 0 14 1 x 10-14
Example1. If the [H+] in a solution is 1.0 x 10-5M, is the
solution acidic, basic or neutral?
1.0 x 10-5 M
What is the concentration of the [OH-]?Use the ion-product constant for water (Kw):
Kw = [H+] [OH-] 1.0 x 10-14 = [1.0 x 10-5] [OH-] 1.0 x 10-14 = [OH-] 1.0 x 10-5
1.0 x 10-(14-5)
pH 5 = acidic
1.0 x 10-9 OH-
Examples2. If the pH is 9, what is the concentration of
the hydroxide ion?
Kw = [H+] [OH-]
1.0 x 10-14 = [1.0 x 10-9] [OH-]
1.0 x 10-5 = [OH-]
3. If the pOH is 4, what is the concentration of the hydrogen ion?
Kw = [H+] [OH-]
1.0 x 10-14 = [H+] [1.0 x 10-4]
1.0 x 10-10 = [H+]
14 = pH + pOH
14 = 9 + pOH
5 = pOH
14 = pH + pOH
14 = pH + 4
10 = pH
Example
4. A solution has a pH of 4. Calculate the pOH, [H+] and [OH-]. Is it acidic, basic, or neutral?
– pOH = 14.00- 4 = 9
– acidic
M101][OH 9
M4101][H
Fill in the chart.
[OH-] pOH pH [H+]
8
1x 10-12
10
1 x 10-3
5
1 × 10-1
1.0 X 10 -8
1.0 X 10 -2
1.0 X 10 -6
6
2 12
Naming Acids
• Binary acids
– Contains 2 different elements: H and another
– Always has “hydro-” prefix
– Root of other element’s name
– Ending “-ic”
– Examples: HI, H2S, HBr
Naming Acids
• Ternary Acids - Oxyacids
– Contains 3 different elements: H, O, and another
– No prefix
– Name of polyatomic ion
– Ending “–ic” for “-ate” and “–ous” for “-ite”
– Examples: HClO4, H3PO4, HNO2
Practice
• H2SO3
– Sulfurous acid• HF
– Hydrofluoric acid
• H2Se
– Hydroselenic acid
• Perchloric acid
– HClO4
• Carbonic acid
– H2CO3
• Hydrobromic acid– HBr
