1. Anything in black letters = write it in your notes (‘knowts’)
UNIT 6 – Acids & Bases & Redox Rxns
Chapter 19 – Acids, Bases, and Salts Chapter 20 – Oxidation-Reduction Rxns
Chapter 19
Acids, Bases, and Salts
Anything in black letters = write it in your notes (‘knowts’)

2. Acids Bases 19.1 – Acid-Base Theories
Taste sour
Dissolve active metals to produce hydrogen gas
Turns litmus paper RED
Bases
Taste bitter
Feels slippery on skin (dissolves oils on skin)
Turns litmus paper BLUE
Have you seen the litmus paper yet??
These are experimental definitions, we need a theoretical…

3. HCl (aq)  H+ (aq) + Cl- (aq) NaOH (aq)  Na+ (aq) + OH- (aq)
Arrhenius’s Definition (~1887)
ACID – substance that forms hydrogen (H+) ions in water.
HCl (aq)  H+ (aq) Cl- (aq)
HCl is an acid because it produces H+ ions when placed in water.
BASES – substance that forms hydroxide (OH-) ions in water.
NaOH (aq)  Na+ (aq) OH- (aq)
NaOH is a base because it produces OH- ions when placed in water.

4. Lewis Acids and Bases (not covered)
Bronsted-Lowry Acids/Bases (not covered)
Conjugate Acids & Bases (not covered)
Lewis Acids and Bases (not covered)

5. pH = ‘power of the hydrogen ion’
19.2 – Hydrogen Ions and Acidity
The more H+ a substance forms in water, the more acidic the solution becomes.
pH = ‘power of the hydrogen ion’
The pH scale is used to describe how acidic or basic (alkaline) a substance is.

6. [H+] = ‘the hydrogen ion concentration’
Molarity (M) – unit used to express the concentration of a solution
mol solute (mol)
Molarity =
liters of soln (L)
anything in [brackets] means the concentration in molarity
[H+] = ‘the hydrogen ion concentration’
[OH-] = ‘the hydroxide ion concentration’

7. pH = ‘power of the hydrogen ion’
Two methods of measuring pH
pH = ‘power of the hydrogen ion’
Acid-Base Indicators – change color when a change in pH occurs.
pH meters
phenolphthalein, litmus, cabbage, etc…

9. 19.3 – Strengths of Acids and Bases
not covered…

10. Acid + Base  Salt + H2O HCl + NaOH  NaCl + H2O
19.4 – Neutralization Reactions
Neutralization Rxn – complete rxn of a strong base with a strong acid
A neutralization rxn will produce a salt and water.
Acid Base  Salt H2O
HCl NaOH  NaCl H2O

11. Standard – solution of known concentration.
Titration – determining the concentration of an unknown solution using a solution whose concentration is known.
Standard – solution of known concentration.
Equivalence Point – point where the amount of acid equals the amount of base
End Point – point where the indicator changes color 11

12. HCl + NaOH  NaCl + H2O EXAMPLE x M 0.5 M 10.0 mL 20.0 mL
10.0 mL of 0.5 M HCl solution is added to 20.0 mL of NaOH of unknown concentration. What is the concentration of the NaOH?
HCl NaOH  NaCl H2O
x M
0.5 M
10.0 mL
20.0 mL
Since the reaction of HCl and NaOH is 1:1 and twice the volume of NaOH was used, the NaOH must half as strong as HCl; [0.25 M].

13. Always adjust if the rxn is NOT 1:1
EXAMPLE
What volume of 0.10 M KOH is required to neutralize 20.0 mL of 0.20 M H2SO4 solution?
H2SO KOH  K2SO H2O
0.20 M
0.10 M
20.0 mL
x mL
Always adjust if the rxn is NOT 1:1
Since KOH requires twice as many moles as H2SO4, you should double your answer.

14. Write the balanced chemical equation for each neutralization reaction
Sulfuric acid + magnesium hydroxide
Phosphoric acid + calcium hydroxide
Nitric acid + ammonium hydroxide

15. Chapter 19 Sample Quiz Questions
1. What color will litmus paper be in an acidic solution?
2. What color will phenolphthalein indicator be in an basic solution?
3. Define an acid in terms of H+ ions.
4. What two products are always formed in an acid-base neutralization reaction?
5. HCl (aq) + KOH (aq)  ______ + _______

16. 19.5 – Salts in Solution
not covered…