1. CVEN 5424 Environmental Organic Chemistry Lecture 2 – Organic Chemistry and Thermodynamics

2. Announcements Reading Chapter 2 Chapter 3 (skim sections 3.1 and 3.2) Problem sets PS 1 out today, due next Thursday due at beginning of class; if late, will not be graded write neatly or type; box your answers consider significant figures – not too many, but enough cite sources for data

3. Announcements Office hours – proposed Tuesday 8:30-10:00 am Wednesday 1:00-3:00 pm Doodle poll to maximize availability Room SEEC C326 (RASEI Fellows Conf Rm) today, next week SEEC S298 rest of the semester, starting Tues Jan 26 Lectures no lecture Thur Jan 28

4. Organic Chemistry What is the molecular formula of phenol? C 6 H 6 O What is a structural formula of phenol? C 6 H 5 OH What is the structure of phenol?

5. Organic Chemistry What is an ionic bond? a transfer of electrons between two elements in a molecule; transfer of electron fills electron shell; elements of different “ electronegativity (e.g., Na + and Cl - )

6. Organic Chemistry What is a covalent bond? a sharing of a pair of electrons between two elements; elements of similar electronegativity (e.g., C, H, O, S, N, P) molecular orbitals 1s, 2s, 2p, 3s, 3p, 3d, … bonding orbitals hydribization of molecular orbitals

7. Organic Chemistry Orbitals

9. Organic Chemistry

10. Aufbau Principle lowest energy orbitals filled first Hund’s Rule in unfilled orbitals, electrons go into different orbitals rather than pairing up in the same orbital 10 (notice the unpaired electrons have parallel spins)

11. Organic Chemistry 11

12. Organic Chemistry Single bond sharing of 1 pair of electrons Double bond sharing of 2 pairs of electrons Triple bond sharing of 3 pairs of electrons 12

13. Organic Chemistry Bond hybridization sp 3 – single bond sp 2 – double bond sp – triple bond

14. Organic Chemistry Bond hydridization sp 3 – single bond – tetrahedral overlap of one s and three p orbitals sp 2 – double bond sp – triple bond methane, CH 4

15. Organic Chemistry Review Bond hydridization sp 3 – single bond – tetrahedral overlap of one s and three p orbitals sp 2 – double bond sp – triple bond ethane, H 3 C-CH 3

16. Organic Chemistry Review Bond hydridization sp 3 – single bond sp 2 – double bond – planar overlap of one s and two p orbitals sp – triple bond ethene C 2 H 4

17. Organic Chemistry Review Bond hydridization sp 3 – single bond sp 2 – double bond sp – triple bond – linear overlap of one s and one p orbital ethyne C 2 H 2

18. Organic Chemistry Review Bond hydridization sp 3 d – trigonal bipyramid overlap of one s, three p, and one d orbital phosphorus(V) sp 3 d 2 – octahedral

19. Organic Chemistry Review Bond hydridization sp 3 d – trigonal bipyramid sp 3 d 2 – octahedral overlap of one s, three p, and two d orbitals

20. Organic Chemistry Bond hydridization

21. Organic Chemistry Bond hydridization -- VSEPR Valence Shell Electron Pair Repulsion

23. a complete table Linus Pauling

24. a complete table

25. Organic Chemistry Review How does electronegativity affect covalent bonding? The “electron cloud,” or average electron position, between the two atoms is shifted toward the atom that more strongly attracts electrons

26. Organic Chemistry Types of covalent bonds if electrons are shared evenly, the bond is nonpolar covalent if electrons are not shared evenly, the bond is polar covalent 26

27. Organic Chemistry Intramolecular bond strengths Ionic bonds  400-4000 kJ mol -1 Covalent  150-1100 kJ mol -1 Metallic  75-1000 kJ mol -1 Intermolecular bond strengths H-bond  10-40 kJ mol -1 Dipole-dipole  5-25 kJ mol -1 Dipole-induced dipole  2-10 kJ mol -1 Dispersion (London)  0.05-40 kJ mol -1 27

28. Organic Chemistry Which bond do you think is the strongest? A. C – F B. C – Cl C. C – Br D. C – I bond length (Å) 1.38 1.78 1.94 2.14

29. Organic Chemistry Which bond do you think is the strongest? A. C – F B. C – Cl C. C – Br D. C – I bond length (Å) 1.38 1.78 1.94 2.14 486 kJ mol -1 339 kJ mol -1 281 kJ mol -1 216 kJ mol -1

30. Hydrogen Bonding Why are hydrogen bonds formed? hydrogen covalently bonds with an electronegative heteroatom (O, S, N) H electron is pulled to O; forms proton (+) proton attracts other electronegative atoms bond strength ~ 20 kJ mol -1

31. Delocalized Electrons Do delocalized electrons make a compound more or less stable? The restraints on electron positions are diminished, their energy levels are lowered, and hence, the compound is more stable. delocalized electrons = double, triple bonds = stronger bonds

32. Delocalized Electrons What are two common functional groups that “resonate?” carboxylnitro

33. Delocalized Electrons What are two common functional groups that “resonate?” carboxylnitro functional groups

34. Next Lecture Thermodynamics Chapter 3 Vapor pressure Chapter 4