Chapter 8 Notes
Chem210FL
page 1
Dr. Lara Baxley
Chapter 14 Notes: Acids and Bases (sections 1,2,5,6)
I. Acids and Bases Learning Goal Describe and name Arrhenius acids and bases
and simple carboxylic acids.
A. Arrhenius Acids and Bases
Arrhenius Acid: Produce a proton (H+) in water. egs: HCl, H2SO4
HCl → H+ + Cl–
Arrhenius Base: Produce OH– in water. egs: NaOH, Ca(OH)2
NaOH → Na+ + OH–
B. Carboxylic Acids
II. Ionization of Water (book section 5) Learning Goal Use the ion product of water
to calculate the [H3O+] and [OH–] in an aqueous solution.
A. Using Brackets to Express Concentration
[ ] around a substance means the concentration of this in mol/L
example: “What is the [OH–]?”
–
means “What is the concentration of OH in mol/L?”
B. Ionization of Water
In pure water, only 1 in about every 550,000,000 water molecules is ionized.
Chapter 8 Notes
Chem210FL
page 2
Dr. Lara Baxley
C. Ion Product Constant for Water, Kw
H2O(l) + H2O(l) ⇌ H3O+(aq) + OH–(aq)
Example:
Calculate the molar concentration of OH– in an aqueous solution that has an
H3O+ of 3.25 x 10–4 M. (always assume 25 °C)
D. Acidic, Basic and Neutral Solution
H2O(l) + H2O(l) ⇌ H3O+(aq) + OH–(aq)
Kw = [H3O+][OH–] = 10–14
In neutral solution,
In acidic solution,
In basic solution,
Practice
Calculate the concentration of [OH–] in a solution with [H3O+] = 5.47 x 10–5 M. Is
this solution acidic or basic?
III. The pH Scale (book section 6) Learning Goals Calculate the pH from [H3O+] or
[OH–]; given pH, calculate [H3O+] and [OH–].
A. The pH Scale
Chapter 8 Notes
Chem210FL
page 3
Dr. Lara Baxley
B. Measuring pH
C. pH and pOH
For basic solutions, it might make sense to use pOH:
However, then we’d have to have pOH meters and pOH strips, so instead we
use an equation to calculate between pH and pOH:
D. Calculating [H3O+] and [OH–] from pH
Two more equations:
All of these equations are related:
Practice
1. What is the pH of 1.23 x 10–5 M HCl?
2. What concentration of HNO3 will have a pH = 2.21?
3. What is the concentration of [OH–] if pH = 10.85?
4. What is the pH of 0.0095 M NaOH?
Chapter 8 Notes
Chem210FL
page 4
Dr. Lara Baxley
IV. Brønsted-Lowry Acids and Bases (book section 2) Learning Goal Identify
conjugate acid-base Pairs for Brønsted-Lowry acids and bases.
A. Brønsted-Lowry Acids and Bases
Brønsted-Lowry Acid:
Brønsted-Lowry Base:
Examples:
B. Conjugate Acid-Base Pairs
HF + NH3 ⇌ F– + NH4+
NH3 + H2O ⇌ NH4+ + OH–
Chapter 8 Notes
Chem210FL
Practice
1. Write the conjugate base of each of the following.
a. HC2H3O2
b. HClO
c. H2SO4
2. Write the conjugate acid of each of the following.
a. CO32–
b. H2PO4
c. H2O
Suggested textbook problems:
Ch14: Within Chapter: 1,3,7,9,11,13,35,37,39,41,43,45,49,51
End of Chapter: 75,79(a-c,e),81,85,87,89,91,93,*95,105,**109,111
page 5
Dr. Lara Baxley