1. Chapter 3
Chem 341
Suroviec Fall 2016

2. I. Water
Nearly all biomolecules assume their shape due to water
Polar Molecule
Central oxygen forms covalent bonds with two hydrogen atoms, leaving 2 unshared electrons

3. B. Types of Interactions
Non-covalent interactions
Ionic
Hydrogen-bonds
Dipole-dipole
Dipole-induced dipole
London dispersion

4. Table 2-1

5. C. Hydrophobic, Hydrophilic and Amphiphillic
Water sticks together
Non-polar sticks together
Affects entropy
Hydrophilic
Polar water will dissolve ionic and polar substances
Amphophilic
Polar and Nonpolar
Forms micelles and bicelles

6. II Properties of Water
Polar Molecule
High heat of vaporization
C. High heat capacity D. High melting/boiling point

7. III. Chemical Properties
Water as a solvent
Ability to form H-bonds
B. Hydrophobic effect
Nonpolar substance does not dissolve but phase separates

8. IV. Acids, Bases and pH
Water ionization
2. pH of a solution

9. D. Acids, Bases and pH
Acid dissociation
Base dissociation

10. D. Acids, Bases and pH
5. pka = -log Ka
Acids are classified by Ka
Weak acids: Ka < 1 (partially dissociated)
Strong acids: Ka >1 (completely dissociated)

11. D. Acids, Bases and pH
Buffers
Conjugate acid/base combination that over a small pH range resists changes in pH

12. D. Acids, Bases and pH