1. Hydrocarbons CxHyCxHy Hydrides of Carbon

2. Carbon has four valence electrons. Wants to form four bonds. Hydrogen has one valence electron and wants to form one bond Methane

3. Ethane Propane Butane

4. Methane CH 4 Ethane C 2 H 6 Propane C 3 H 8 Butane C 4 H 10

6. Ethane Conformations Staggered Eclipsed

7. 0 60 120 180 240 300 360 Angle of Rotation, degrees 12 kJ Variation of Energy with Rotation of C-C bond in Ethane

9. Butane C 4 H 10 n- 2-methylpropane or isobutane These two molecules are structural isomers. They differ in the way their atoms are connected They have different chemical and physical properties.

10. 2-methylpropane or isobutane

11. n-hexane These structures represent different conformations of n-hexane, not isomers.

12. n-hexane 2-methylpentane 3-methylpentane 4-methylpentane 2,3-dimethylbutane2,2-dimethylbutane

13. These are the five isomers of hexane, C 6 H 14

14. Methane becomes Methyl Ethane becomes Ethyl Propane becomes Propyl

15. 1MethaneMethyl 2EthaneEthyl 3PropanePropyl 4ButaneButyl 5PentanePentyl 6HexaneHexyl 7HeptaneHeptyl 8OctaneOctyl 9NonaneNonyl 10DecaneDecyl

16. Find the longest chain7 carbons. It’s a heptane Number the atoms Add the substituents in alphabetic order 4-ethyl-2-methylheptane

17. 5 carbon chain. It’s a pentane 3 methyls so use the prefix - tri 2di- 3tri- 4tetra- 5penta- 6hexa- 2,2,4-trimethylpentane not 4,4,2-trimethylpentane

18. 9 carbon chain It’s a nonane 2 methyl groups and 1 ethyl group 4-ethyl-3,7-dimethylnonane not 6-ethyl-3,7-dimethylnonane

19. hexane 2-methylpentane 3-methylpentane 2,3-dimethylbutane 2,2-dimethylbutane

21. What is special about this compound? 3-methylhexane These two compounds are different. One Is left handed and the other is right handed. The two compounds are mirror images.

22. Put your thumb toward you representing the hydrogen atom, the lightest group. Point your fingers toward the propyl group, the heaviest group. Curl your fingers toward the ethyl group, the second heaviest group. Left Handed or S Right Handed or R These molecules are Chiral. They have handedness.

23. S-3-ethyl-2-methylhexane

24. Molecular Formulas for Alkanes are all of the form C n H 2n+2 2,2,4-trimethylpentanen-octane n = 8 2n + 2 = 18 C 8 H 18

25. Molecular Formulas for Alkenes are all of the form C n H 2n 2,4,4-trimethyl-2-pentene 1-octene n = 8 2n = 16 C 8 H 16

26. cis-2-pentenetrans-2-pentene If an alkene has two identical substituents on the two different carbons, they can be named cis or trans. If the identical substituents are on the same side we call themolecule cis. If they are on opposite sides we call the molecule trans. The two compounds shown above are stereoisomers.

27. If two substituents on one carbon are the same cis and trans do not apply But what do we do if all groups are different?

28. Instead of cis or trans use E or Z Z means the two heaviest groups are on the same side of the double bond. E means the two heaviest groups are on different sides of the double bond. (E) - 3-methyl-3-heptene(Z) - 3-methyl-3-heptene

29. cis-3,5-dimethyl-2-hexene (E)-2,4-dimethyl-3-hexene 2-ethyl-4-methyl-1-pentene

30. Molecular Formulas for Alkynes are all of the form C n H 2n-2 1-octyne n = 8 2n - 2 = 14 C 8 H 14

31. 2-methyl-3-hexyne 3-ethyl-6-methyl-1-heptyne

32. trans-2-pentenecyclopentane C 5 H 10

33. Cycloalkanes C n H 2n cyclopropanecyclobutane cyclopentanecyclohexane

34. Cyclopropane

35. cis-1,2-dimethylcyclopropane trans-1,2-dimethylcyclopropane

36. trans-1,2-dimethycyclobutane cis-1-ethyl-3-methylcyclobutane

37. Cyclohexane Ideal angles are 120 degrees. Actual angles are 109.5 degrees, the tetrahedral angle

38. Benzene

39. 1,3-dimethylbenzene 1,4-dimethylbenzene 1,2-dimethylbenzene methylbenzene toluene ortho metapara

40. Draw all compounds of formula C 4 H 8 Draw all compounds of formula C 4 H 6 Draw all compounds of formula C 4 H 10