Downloaded 107 times
![pH Scale
ā¢ We use this scale to measure the strength
of an acid or base.
ā¢ pH is defined as the ālog[H+]
ā¢ pH can use the concentration of
hydronium ions or hydrogen ions.](https://image.slidesharecdn.com/phscaleandcalculations-091107004803-phpapp02/75/P-H-Scale-And-Calculations-2-2048.jpg)
![pH of Common Substance
pH [H1+] [OH1-] pOH
14 1 x 10-14 1 x 10-0 0
NaOH, 0.1 M 13 1 x 10-13 1 x 10-1 1
Household bleach
12 1 x 10-12 1 x 10-2 2
More basic
Household ammonia
Lime water 11 1 x 10-11 1 x 10-3 3
Milk of magnesia
10 1 x 10-10 1 x 10-4 4
Borax
9 1 x 10-9 1 x 10-5 5
Baking soda
Egg white, seawater 8 1 x 10-8 1 x 10-6 6
Human blood, tears
Milk 7 1 x 10-7 1 x 10-7 7
Saliva
Rain 6 1 x 10-6 1 x 10-8 8
More acidic
Black coffee 5 1 x 10-5 1 x 10-9 9
Banana
Tomatoes 4 1 x 10-4 1 x 10-10 10
Wine
Cola, vinegar 3 1 x 10-3 1 x 10-11 11
Lemon juice
2 1 x 10-2 1 x 10-12 12
Gastric juice
1 1 x 10-1 1 x 10-13 13
0 1 x 100 1 x 10-14 14](https://image.slidesharecdn.com/phscaleandcalculations-091107004803-phpapp02/75/P-H-Scale-And-Calculations-5-2048.jpg)
![Acid ā Base Concentrations
10-1
pH = 3 pH = 11
concentration (moles/L)
H3O+ OH-
pH = 7
10-7
H3O+ OH-
OH- H3O+
10-14
[H3O+] > [OH-] [H3O+] = [OH-] [H3O+] < [OH-]
acidic neutral basic
Timberlake, Chemistry 7th Edition, page 332 solution solution solution](https://image.slidesharecdn.com/phscaleandcalculations-091107004803-phpapp02/75/P-H-Scale-And-Calculations-6-2048.jpg)
![pH
pH = -log [H+]
Kelter, Carr, Scott, Chemistry A World of Choices 1999, page 285](https://image.slidesharecdn.com/phscaleandcalculations-091107004803-phpapp02/75/P-H-Scale-And-Calculations-7-2048.jpg)
![Self-Ionization Of Water
ā¢ Even the purest of water conducts electricity. This
is due to the fact that water self-ionizes, that is, it
creates a small amount of H3O+ and OH-.
H2O + H2O ļŗ H3O+ + OH-
Kw = [H3O+][OH-]
ā¢ Kw - ion product of water
Kw = 1.0 x 10-14 at 25 oC
ā¢ This equilibrium constant is very important because
it applies to all aqueous solutions - acids, bases,
salts, and non-electrolytes - not just to pure water.](https://image.slidesharecdn.com/phscaleandcalculations-091107004803-phpapp02/75/P-H-Scale-And-Calculations-8-2048.jpg)
![Self ionization reaction of water:
+ -
O O O
H + H H H + O
H H
H H
ļ« ļ
2 H2O ļ« H3 O ļ«OH
ļ« ļ
K w ļ½[H3O ] [OH ] ļ½10 -14
(at 25ļ°
C)
ļ« Kw
[H 3O ] ļ½
[OH-]](https://image.slidesharecdn.com/phscaleandcalculations-091107004803-phpapp02/75/P-H-Scale-And-Calculations-9-2048.jpg)
![pH and pOH
ā¢ pH = - log[H3O+] [H3O+] = 10-pH
pOH = - log[OH-] [OH-] = 10-pOH
ā¢ pKw = pH + pOH = 14.00
ā¢ neutral solution: [H3O+] = [OH-] = 10 ā7 M pH = 7.0
acidic solution: [H3O+] > 10-7 M pH < 7.0
basic solution: [H3O+] < 10-7 M pH > 7.0](https://image.slidesharecdn.com/phscaleandcalculations-091107004803-phpapp02/75/P-H-Scale-And-Calculations-10-2048.jpg)
![Practice
ā¢ Finish the following for homework
Page 566 #12-15 (using Kw)
Page 569 # 16-19 (using pH = -log[H+]
Page 572 # 20-23
Page 578 # 2, 6-8](https://image.slidesharecdn.com/phscaleandcalculations-091107004803-phpapp02/75/P-H-Scale-And-Calculations-11-2048.jpg)
Uploaded byAyurmitra Dr.KSR Prasad
P H Scale And Calculations
1) The pH scale is used to measure the strength of acids and bases, with pH defined as the negative log of the hydronium (H3O+) ion concentration. 2) Common substances span the pH scale from 0 to 14, with examples like stomach acid at pH 1 and bleach/drain cleaners at pH 12-13. 3) The pH of a solution depends on the relative concentrations of H3O+ and OH- ions, with acidic solutions having higher H3O+ and basic solutions having higher OH- concentrations. 4) Water self-ionizes according to the equilibrium H2O + H2O
In this document
Powered by AI
Overview of pH scale used to measure acid/base strength; pH defined as ālog[H+].
Visual representation of pH scale with acid (0) and base (14) extremes.
Listing of pH values for common substances; numerical data from pH 0 (strong acid) to pH 14 (strong base).
Details on acid-base concentrations with pH values; shows relationship between [H3O+] and [OH-] for different solutions.
Equation for calculating pH: pH = -log[H+].
Explanation of water's self-ionization; important equilibrium constant Kw = 1.0 x 10-14 at 25Ā°C.
Formulas for pH and pOH, demonstrating their relationship and concept of neutral vs acidic/basic solutions.
Assignment instructions for practice questions on pH and ionization calculations.
More Related Content
P H Scale And Calculations
- 1. pH Scale andCalculations Chapter 14 Page 565-574
- 2. pH Scale ā¢ Weuse this scale to measure the strength of an acid or base. ā¢ pH is defined as the ālog[H+] ā¢ pH can use the concentration of hydronium ions or hydrogen ions.
- 3. 7 Acid Base 0 pH Scale 14 Zumdahl, Zumdahl , DeCoste, World of Chemistry 2002, page 515
- 4. pH of CommonSubstances Timberlake, Chemistry 7th Edition, page 335
- 5. pH of CommonSubstance pH [H1+] [OH1-] pOH 14 1 x 10-14 1 x 10-0 0 NaOH, 0.1 M 13 1 x 10-13 1 x 10-1 1 Household bleach 12 1 x 10-12 1 x 10-2 2 More basic Household ammonia Lime water 11 1 x 10-11 1 x 10-3 3 Milk of magnesia 10 1 x 10-10 1 x 10-4 4 Borax 9 1 x 10-9 1 x 10-5 5 Baking soda Egg white, seawater 8 1 x 10-8 1 x 10-6 6 Human blood, tears Milk 7 1 x 10-7 1 x 10-7 7 Saliva Rain 6 1 x 10-6 1 x 10-8 8 More acidic Black coffee 5 1 x 10-5 1 x 10-9 9 Banana Tomatoes 4 1 x 10-4 1 x 10-10 10 Wine Cola, vinegar 3 1 x 10-3 1 x 10-11 11 Lemon juice 2 1 x 10-2 1 x 10-12 12 Gastric juice 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14
- 6. Acid ā BaseConcentrations 10-1 pH = 3 pH = 11 concentration (moles/L) H3O+ OH- pH = 7 10-7 H3O+ OH- OH- H3O+ 10-14 [H3O+] > [OH-] [H3O+] = [OH-] [H3O+] < [OH-] acidic neutral basic Timberlake, Chemistry 7th Edition, page 332 solution solution solution
- 7. pH pH = -log [H+] Kelter, Carr, Scott, Chemistry A World of Choices 1999, page 285
- 8. Self-Ionization Of Water ā¢Even the purest of water conducts electricity. This is due to the fact that water self-ionizes, that is, it creates a small amount of H3O+ and OH-. H2O + H2O ļŗ H3O+ + OH- Kw = [H3O+][OH-] ā¢ Kw - ion product of water Kw = 1.0 x 10-14 at 25 oC ā¢ This equilibrium constant is very important because it applies to all aqueous solutions - acids, bases, salts, and non-electrolytes - not just to pure water.
- 9. Self ionization reactionof water: + - O O O H + H H H + O H H H H ļ« ļ 2 H2O ļ« H3 O ļ«OH ļ« ļ K w ļ½[H3O ] [OH ] ļ½10 -14 (at 25ļ° C) ļ« Kw [H 3O ] ļ½ [OH-]
- 10. pH and pOH ā¢pH = - log[H3O+] [H3O+] = 10-pH pOH = - log[OH-] [OH-] = 10-pOH ā¢ pKw = pH + pOH = 14.00 ā¢ neutral solution: [H3O+] = [OH-] = 10 ā7 M pH = 7.0 acidic solution: [H3O+] > 10-7 M pH < 7.0 basic solution: [H3O+] < 10-7 M pH > 7.0
- 11. Practice ā¢ Finish thefollowing for homework Page 566 #12-15 (using Kw) Page 569 # 16-19 (using pH = -log[H+] Page 572 # 20-23 Page 578 # 2, 6-8