1. Acids and Bases

2. Chemistry Joke
THE BASE IS UNDER A SALT!

3. Acids and bases
Acids and bases are two classes of chemical compounds that we encounter frequently in everyday living.
Vinegar and lemon juice are common acids.
Ammonia and bleach are common bases.
Acids and bases have opposite properties and the ability to cancel or neutralize each other.
Almost all acids begin with H+, and most bases end with OH-.

4. Properties of acids Taste sour Are strong or weak electrolytes
React with bases to form water and salts
React with active metals to produce H2
Turn litmus (and cabbage) red
Low pH

5. Naming Acids—a review Anion Ending Example Acid Name -ide
Cl-, chloride
Hydro-(stem)-ic
Hydrochloric acid, HCl
-ite
SO32-, sulfite
(stem)-ous
Sulfurous acid, H2SO3
-ate
NO3-, nitrate
(stem)-ic
Nitric acid, HNO3

6. Properties of bases Taste bitter Are strong or weak electrolytes
React with acids to form water and salts
Feel slippery
Turn litmus (and cabbage) blue
High pH

7. Two Acid/Base Theories
Arrhenius
Bronsted- Lowry

8. Arrhenius Simplest definition and most restrictive
Acids supply H+ ions
Bases supply OH- ions

9. Bronsted-Lowry Added to Arrhenius definition of bases
Acids are proton (H+) donors
But…
Bases are proton (H+) acceptors
Don’t necessarily have to supply OH-
NH3 (ammonia) can now be recognized as a base.

10. Conjugate Acid/base Pairs
Bronsted-Lowry also defined conjugate acids and bases.
HA H2O A− + H3O+
HA is an acid. The product A- is its conjugate base.
H2O is behaving as a base. The product H3O+ is its conjugate acid.
These pairs differ by only one H+.
The compound with the extra H+ is the acid.

11. Self-ionization of water
Sometimes when water molecules collide, a hydrogen ion transfers.
H20 + H20  H3O+ + OH-
Hydronium ion
Hydroxide ion
Sometimes the self-ionization of water is shown as: H20(l)  H+(aq)+ OH-(aq)
H+ and H3O+ are often used interchangeably.
Water can act as both an acid and a base, producing both H+ and OH- ions.

12. Strong acids and Bases
Strength in acids and bases does NOT refer to how corrosive or dangerous they are.
Strong acids and bases dissociate (break apart) completely in water.
At equilibrium, there is no acid or base left that has not ionized (separated into its ions)
One of the most corrosive and dangerous acids, HF, is actually a weak acid.

13. Strong vs. weak
hang7/esp/folder_structure/ac/m2/s1/acm2 s1_1.htm

14. Acid / Base neutralization
When an acid reacts with a base, both are neutralized as water and a salt are produced.
Predict the products and write the balanced equation for the reaction of sulfuric acid with potassium hydroxide.

15. Chemistry Joke
Q: Why do chemistry professors like to teach about ammonia?
A: Because it’s very basic material!