1. I. Intro to Acids & Bases (p.236-241) Definitions Properties Uses
Ch. 7 - Acids & Bases
I. Intro to Acids & Bases (p )
Definitions
Properties
Uses

2. HCl + H2O  H+ + Cl– H3O+ + Cl–
A. Definitions
Acids
Ionize to form hydrogen ions (H+) then hydronium ions (H3O+) in water
HCl + H2O  H+ + Cl– H3O+ + Cl–

3. NH3 + H2O  NH4+ + OH- A. Definitions Bases
Dissociate or ionize to form hydroxide ions (OH-) in water
NH3 + H2O  NH4+ + OH-

4. A. Definitions Indicator
substance that changes color in an acid or base
Examples:
litmus - red/blue
phenolphthalein - colorless/pink
goldenrod - yellow/red
red cabbage juice - pink/green

5. B. Properties ACIDS BASES sour taste corrosive electrolytes
turn litmus red
react with metals to form H2 gas
bitter taste
corrosive
electrolytes
turn litmus blue
slippery feel

6. C. Uses ACIDS H3PO4 - soft drinks, fertilizer, detergents
H2SO4 - fertilizer, car batteries
HCl - gastric juice
HC2H3O2 - vinegar

7. C. Uses BASES NaOH - lye, drain and oven cleaner
Mg(OH)2 - laxative, antacid
NH3 - cleaners, fertilizer

8. Acids and Bases in Solution
Acids in Solution
Acids are made of a H+ ion and an Anion (a negatively charged ion)
In water, acids dissociate (breakdown) into H+ and anions
1. HCl  H+ + Cl-
Bases in solution
Most bases release hydroxides ions into the water
1. NaOH  Na+ + OH-
2. NH3 + H2O  NH4 + OH- 8

9. Acid / Base Reactions
When Acids and Bases are combined a Neutralization reaction produces water and a salt
1. Hydrochloric Acid and Sodium Hydroxide yields water and Sodium Chloride
a. HCl + NaOH  H2O + NaCl
B. H+ + Cl- + Na+ + OH-  H2O + NaCl
2. Salt is an ionic compound formed from an acid / base reaction (neutralization) 9

10. II. Strength of Acids & Bases (p. 242-247) Strong vs. Weak pH
Ch. 7 - Acids & Bases
II. Strength of Acids & Bases (p )
Strong vs. Weak pH

11. A. Strong vs. Weak Strong Acid/Base 100% ions in water
strong electrolyte
HCl, HNO3, NaOH, LiOH - +
Weak Acid/Base
few ions in water
weak electrolyte
HC2H3O2, NH3 - +

12. ConcepTest
Which of the following "molecular" pictures best represents a concentrated solution of the weak acid HA? A B

13. Strength of Acids Remember Acids are compounds that:
Release free Hydrogen ions into solution (H+)
Reacts with metals and carbonates
Turns blue litmus paper red
Tastes sour (never taste)
Are corrosive, eating away
“Need-to-Know “Acids”:
Hydrochloric HCl
Nitric Acid HNO3
Sulfuric Acid H2SO4
Carbonic Acid H2CO3 13

14. Strength of Bases Remember Bases are compounds that:
1. Release hydroxide ions (OH-) into solution
ii. Have a bitter taste (never taste any solution unless told to do so)
iii. feel slippery
iv. React with indicators like litmus by turning red litmus blue
v. have a pH greater than 7.0
“Need-to-Know “Bases”:
Sodium Hydroxide NaOH
Potassium Hydroxide KOH
Calcium Hydroxide Ca(OH)2
Ammonia NH3 14

15. B. pH Scale pH
a measure of the concentration of H+ or H3O+ ions in solution
measured with a pH meter or an indicator with a wide color range 7
INCREASING
ACIDITY
NEUTRAL
BASICITY 14

16. pH of Common Substances
B. pH Scale
pH of Common Substances

17. Water & pH pH = -(log[H+])= -(log[10-7]) pH=- (-7) = pH 7
At equilibrium, the concentration of H+ (Hydronium) is 10-7
so we can calculate the pH of water at equilibrium as:
pH = -(log[H+])= -(log[10-7])
pH=- (-7) = pH 7
pH scale goes from 0 to 14 17

18. ConcepTest Is the following statement TRUE or FALSE?
A strong acid has a lower pH than a weak acid.
FALSE - Strong/weak refers to amount of ionization whereas pH refers to concentration of H+.

19. Digestion and pH What is Digestion?
Digestion breaks down food (complex molecules) into smaller molecules
It has two parts (Mechanical and Chemical)
Where does mechanical digestion start?
Your Mouth (chewing)

20. Digestion and pH
Chemical Digestion is helped by pH levels and enzymes (catalysts)
Where does chemical digestion start?
Your mouth
Mouth: pH is near 7, amylase enzymes start to break down carbohydrates (try the bread test)
Stomach; pH is near 2 (acidic) and pepsin enzymes break down proteins
Small Intestine: pH is near 8 (basic) and enzymes finish breaking down carbs, fats and proteins

21. Digestion and pH