2. C-H bonds in methane

3. Figure 22.2: (a) Lewis stucture of ethane (C2H6). (b) molecular structure of ethane HYBRIDIZATION?

4. Name calling methane

5. Name calling ethane

6. Name calling propane

7. Name calling butane

8. Name calling pentane

9. Name calling hexane

10. Name calling heptane

11. Name calling octane

12. Name calling CH 4 methane C 2 H 6 ethane C 3 H 8 propane C 4 H 10 butane C 5 H 12 pentane C 6 H 14 hexane C 7 H 16 heptane C 8 H 18 octane

13. Figure 22.3: Structures of (a) propane (b) butane HYBRIDIZATION?

14. Figure 22.3: Structures of (a) propane (b) butane

15. C C C C C C C

18. C C C C

19. CH 3 CH CH 3

20. C H C H

21. Reactions of Alkanes Combustion alkane + O 2 CO 2 + H 2 O + heat

22. Learning Check Alk3 Complete and balance the reaction for the complete combustion of C 7 H 16

23. Solution Alk3 Step 1 C 7 H 16 + O 2 CO 2 + H 2 O Step 2 C 7 H 16 + O 2 7 CO 2 + 8 H 2 O Step 3 C 7 H 16 + 11 O 2 7 CO 2 + 8 H 2 O

24. Combustion In the Cell Metabolic oxidation is combustion C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + heat glucose How does this reaction occur in living organisms?

25. Aerobic Oxidation Occurs in a Mitochondrion Located within a Cell

27. Branched Alkanes Structural Formulas Structural Isomers

28. Alkyl Groups Branches on carbon chains H H CH methane H H H H C CH ethane H H

29. Alkyl Groups Branches on carbon chains H H C CH 3 methyl H H H H C C CH 3 CH 2 ethyl H H

30. Branched Alkanes CH 3 CH 3 CHCH 3 methyl groups CH 3 CH 3 CH 3 CHCH 2 CHCH 3

31. Naming Branched Alkanes CH 3 methyl branch CH 3 CH 2 CH 2 CHCH 2 CH 3 6 5 4 3 2 1Count

32. Naming Branched Alkanes CH 3 methyl branch CH 3 CH 2 CH 2 CHCH 2 CH 3 6 5 4 3 2 1Count 3-Methylhexane on third C CH 3 six carbon chain group

33. Naming Summary 1. Count the C’s in the longest chain 2. Name each attached group 3 Count the longest carbon chain to give the first attached group the smallest number 4. Name and locate each group

34. Learning Check Alk4 A. CH 3 CH 3 CHCH 2 CH CH 3 CH 3 B. CH 3 CH 3 CH 3 CH 2 CHCH 2 CH CH 3 CH 2 CH 3

35. Solution Alk4 A. CH 3 CH 3 CH 3 CHCH 2 CHCH 3 2,4-dimethylpentane B. CH 3 CH 3 CH 3 CH 2 CHCH 2 CHCH 2 CH 3 CH 3 3,3,5-trimethylheptane

36. Learning Check Alk5 Write a condensed structure for A. 3,4-dimethylheptane B. 2,2-dimethyloctane

37. Solution Alk5 A. 3,4-dimethylheptane CH 3 CH 3 CH 2 CHCHCH 2 CH 2 CH 3 CH 3 B.2,2-dimethyloctane CH 3 CH 3 CCH 2 CH 2 CH 2 CH 2 CH 2 CH 3 CH 3

38. Isomers  Same molecular formula  Same number and types of atoms  Different arrangement of atoms

39. Butane structures n-butane methylpropane

40. Learning Check Alk6 Write 3 isomers of C 5 H 12 and name each.

41. Solution Alk6 CH 3 CH 2 CH 2 CH 2 CH 3 pentane or n-pentane CH 3 CH 3 CHCH 2 CH 3 2-methylbutane CH 3 CH 3 CCH 3 2,2-dimethylpropane CH 3

42. Cyclopropane structure Cyclic Alkanes

43. Cyclohexane structure

44. Figure 22.11: The structure of benzene

45. Naming Cycloalkanes with Side Groups Number of Naming side groups OneSide group name goes in front of the cycloalkane name. TwoNumber the ring in the direction that gives the lowest numbers to the side groups.

46. Cycloalkanes with Side Groups

47. Learning Check Alk8 Name the following cyclic alkanes

48. Solution Alk8

49. Saturated and Unsaturated Compounds Saturated compounds (alkanes) have the maximum number of hydrogen atoms attached to each carbon atom Unsaturated compounds have fewer hydrogen atoms attached to the carbon chain than alkanes Unsaturated compounds contain double or triple bonds

50. Alkenes  Carbon-carbon double bonds  Names end in -ene H 2 C=CH 2 ethene (ethylene) H 2 C=CH-CH 3 propene (propylene) cyclohexene

51. Alkynes  Carbon-carbon triple bonds  Names end in -yne HC  CHethyne(acetylene) HC  C-CH 3 propyne

52. Naming Alkenes and Alkynes When the carbon chain has 4 or more C atoms, number the chain to give the lowest number to the double or triple bond. 1 2 3 4 CH 2 =CHCH 2 CH 3 1-butene CH 3 CH=CHCH 3 2-butene CH 3 C  CCH 3 2-butyne

53. Learning Check HA3 Write the IUPAC name for each of the following unsaturated compounds: A.CH 3 CH 2 C  CCH 3 CH 3 B. CH 3 C=CHCH 3 C.

54. Solutions HA3 Write the IUPAC name for each of the following unsaturated compounds: A.CH 3 CH 2 CH=CHCH 3 2-pentyne CH 3 B. CH 3 C=CHCH 3 C. 2-methyl-2-butene 3-methylcyclopentene

55. Calling names ALKANES ALKENES ALKYNES CYCLO- ALKYL-

56. Hydrogenation Adds a hydrogen atom to each carbon atom of a double bond H H H H + Ni H–C=C–H H–C–C–H H H H H ethene ethane

57. Products of Hydrogenation Adding H 2 to vegetable oils produces compounds with higher melting points Margarines Soft margarines Shortenings (solid)

58. Figure 22.11: The structure of benzene

59. Figure 22.12: Some selected substituted benzenes and their names

60. Compounds containing aromatic rings are often used in dyes, such as these for sale in a market in Nepal Source: Getty Images

61. Bonding in ethane

62. Bonding in ethylene

63. Bonding in acytylene

64. Cis and Trans Isomers  Double bond is fixed  Cis/trans Isomers are possible CH 3 CH 3 CH 3 CH = CH CH = CH cis trans CH 3

65. Vision begins with a light induced cis-trans isomerization reaction of retinal

67. isomers Structural – chain Structural - position Structural – function Stereo - geometrical Stereo - optical butane methyl propane 2methylhexane 3methylhexane cis trans

68. STEREO-ISOMERS Non-Superimposable Mirror Images

75. Electromagnetic Radiation

76. (b)

77. Figure 20.13: Unpolarized light consists of waves vibrating in many different planes

78. Figure 20.14: Rotation of the plane of polarized light by an optically active substance.

79. Optical Isomer and Interaction with Light Enatiomers rotate the plane of polarized light. Dextrorotatory- “d” isomer Complex which rotates plane of polarized light to the right. Levorotatory- “l” isomer Complex which rotates plane of polarized light to the left. Chiral molecules are optically active because effect on light

81. Polarizing sun glasses reduce glare of polarized reflections from surfaces