1. Acid/Base Reactions
Importance of Acid-Base Reactions: Acid-base chemistry is most important in aqueous (water) environments. Since both our planet and our bodies are essentially 2/3 water, this chemistry is critically important to life on earth.

2. Enzymes are proteins that catalyze virtually all important reactions in our bodies needed to keep us alive
The substrates (reactants) bind in a cleft on the surface of the enzyme called the active site. The active site is complementary to the size and shape of the substrates and creates an ideal microenvironment for the desired reaction to take place.

3. Proteins can be unfolded by changes in the amount of acid and base present in the environment
When the shape of a protein changes, it can no longer catalyze the chemical reactions in our cells needed to keep us alive.
Very acidic or basic solution

5. Review of H and the Proton
Hydrogen, the simplest element, consists of a
and an
PROTON
ELECTRON. e-
If you remove the electron from an H atom, only the proton remains.

6. Review of H and the Proton
Hydrogen, the simplest element, consists of a
and an
PROTON
ELECTRON. e- H+
Our symbol for proton is:
If you remove the electron from an H atom, only the proton remains.

7. Bronsted-Lowry Definition of Acids and Bases:
ACIDS are H+ DONORS
BASES are H+ ACCEPTORS H+
HCl + H2O  Cl– + H3O+
acid
base
IN AN ACID BASE REACTION, AN ACID TRANSFERS AN H+ TO A BASE

8. Bronsted-Lowry Definition of Acids and Bases:
ACIDS are H+ DONORS
BASES are H+ ACCEPTORS
IN AN ACID BASE REACTION, AN ACID TRANSFERS AN H+ TO A BASE

9. Properties of Acids and Bases
Taste: Bitter
Feel: Slippery
Taste: Sour
Feel: Stings
Drano, Baking Soda, Window, Cleaners
Wine, vinegar, aspirin lemons, limes

10. Indicators
Indicators are chemicals that turn different colors in acids or bases (different pHs).
Acid in phenolphthalein = colorless
Base in phenolphthalein = magenta pink/purple
Video phenolpthalein

11. Properties continued nitric HCl Acids always react with active metals.
Bases generally do not react with metals. Exception: Al + NaOH
nitric
HCl

12. Sulfuric Acid oxidizing sugar
H2SO4 with Sugar Video

13. Be able to recognize these as Acids or Bases in a chemical rxn
Hydrochloric acid = HCl
Nitric acid = HNO3
Acetic acid = CH3COOH (or C2H3O2H)
water = H2O

14. Be able to recognize these as Acids or Bases in a chemical rxn
Ammonia (covalent) = NH3
Sodium hydroxide (ionic) = NaOH
Ions: Na+1 + OH-1
Potassium hydroxide (ionic) = KOH
Ions: K+1 + OH-1
Water = H2O

15. Patterns: Acid-Base Conjugate Pairs
HA → H+ + A-
Acid conjugate base of HA
HA and A- are conjugate pairs because they differ by an H+
B- + H+ → HB
Base conjugate acid of B-
B- and HB are conjugate pairs because they differ by an H+

16. Recognizing Patterns: Acid-Base Conjugate Pairs always differ by an H+
HCl + H2O  Cl– + H3O+
acid
conjugate base
base
conjugate acid
HCl and Cl- are conjugate pairs;
H2O and H3O+ are conjugate pairs

17. Recognizing Patterns: Conjugate Acid-Base Pairs
Give the conjugate base for each of the following:
HNO3
NO3 -1
C2H3O2H
C2H3O2-1
HCl
Cl-
OH-
H2O

18. Recognizing Patterns: Conjugate Acid-Base Pairs
Give the conjugate acid for each of the following:
NH3
NH4+1
OH -1
H2O
H2O
H3O+1

19. Example Reaction #1:
Video Link
NH3 + HCl →
Base

20. Example Reaction #1:
Video Link
NH3 + HCl →
Base

21. NH3 + HCl → NH4 +1 Cl -1 (OR COULD WRITE AS NH4Cl)
Example Reaction #1:
Video Link H+
NH3 + HCl →
NH4 +1
Cl -1 +
Base
Acid
(OR COULD WRITE AS NH4Cl)

22. Water is amphoteric meaning it can act as ACID or a BASE
In a problem with a different chemical, identify the other chemical besides water as the acid or the base.

23. Example #2: Water as an Acid
NH3 + H2O 
Base

24. Example #2: Water as an Acid
NH3 + H2O 
Base
Acid

25. Example #2: Water as an AcidH+
NH3 + H2O 
NH4+
OH- +
Base
Acid

26. Example #3: Water as a BaseH+
H2O + HNO3  A B

27. Example #3: Water as a Base
H2O + HNO3  H3O+ + NO3– B A CA CB

28. Example #4: Ionic Bases: Must dissociate ions first
HCl + NaOH
Animation
NaOH (aq) + HCl(aq) →
Ionic base Acid
Na OH H+ Cl-
H2O + Na Cl- or NaCl
NaOH (aq) + HCl(aq) → H2O + NaCl

29. Example #5: Ionic Bases: Must dissociate ions first
HNO3 (aq) + KOH(aq) →
Acid Ionic base
H+ NO K OH-1
H2O + K+1 + NO3- or KNO3
HNO3(aq) + KOH (aq) → H2O + KNO3