1. Acids & Bases

2. Aqueous solutions (aq)
~60% of the human body is water
Most chemical reactions inside our body require water or occur in a water solution
When a solid is dissolved in water, the water allows the solid atoms to move around and react easier

3. Properties of Acids Taste sour Turn blue litmus paper red
solutions conduct electricity
React with certain metals to produce hydrogen gas
React with carbonates (CO3) to produce carbon dioxide

4. Properties of Bases Taste bitter Feel slippery
Turn red litmus paper blue
Produce solutions that conduct electricity

5. Arrhenius Definition Acid Base
Substance that contains hydrogen and produces hydrogen ions (H+) in aqueous solutions
HCl  H+ + Cl-
Base
Contains a hydroxide group (OH) and dissociates to produce hydroxide ions in aqueous solutions
NaOH  Na+ + OH-

6. Practice Problem 1
Based on their formulas, which of the following compounds may be Arrhenius acids: CH4, SO2, H2S, Ca3(PO4)2 Explain your reasoning.

7. Bronsted-Lowry Definition
Acid
Hydrogen ion donor
HCl + H2O  H30+ + Cl-
Base
Hydrogen ion acceptor
NH3 + H2O  NH4+ + OH-

8. Acids, Bases or Neutral
All water (aqueous) solutions contain hydrogen ions (H+) and hydroxide ions(OH-)
The amounts of the two ions determine whether a solution is acidic, basic or neutral

9. Acidic solution Basic solution Neutral solution H+ > OH-
OH- > H+
Neutral solution
H+ = OH-

10. Acid – Base Reactions
Special type of reaction that occurs in aqueous solutions (water)
Acid and base are reactants
Proton (H+) transfers from acid to base

11. Conjugate Acid- Base Pairs
Two substances related to each other by the donating and accepting of a single hydrogen ion
Example:
HCl + H2O  H30+ + Cl-

12. Practice Problem 2
Determine the acid-base conjugate pairs for the following chemical reaction: H3PO4 + H2O  H3O+ + H2PO4-

13. Amphoretic Substances that can act as both an acid and a base
Examples: Water
HCl + H2O  H30+ + Cl-
NH3 + H2O  NH4+ + OH-