1. Chapter 6 Organic Chemistry
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2. Carbon
The world contains millions of known compounds, and 95% of them have carbon in common
What is so special about carbon?
Figure 6.1; page 140

3. Carbon (continued) Smallest member and the only nonmetal of group 4A
Forms four covalent bonds
Forms single, double, and triple bonds
Bonds to itself, forming chains, rings, and branched structures
Figure on top is from page 140
Figure at the bottom, page 141

4. Organic Chemistry
Study of carbon-containing compounds and their chemistry
In early 1800s, scientists knew that chemical compounds were of two types
Organic compounds
Came from living organisms and were chemically fragile
Easily decomposed with heat
Inorganic compounds
Came from the earth and were chemically durable
Successfully synthesized by 19th-century chemists

5. Urea Synthesized by Friedrich Wohler in 1828
Organic compound but was synthesized from an inorganic compound
Subsequent death of vitalism
The idea that life was somehow beyond physical laws was proven wrong
Idea that living organisms must follow the physical laws of the universe came into being
Figure 6.3; page 142

6. Types of Organic Compounds
Hydrocarbons
Contain only carbon and hydrogen
Functionalized hydrocarbons
Hydrocarbons that contain additional atoms or groups of atoms called functional groups
Hydrocarbon family can be further divided into subfamilies

7. Figure 6.4: Organic Compounds
Figure 6.4, page 143

8. Alkanes All carbon atoms connected by single bonds
General molecular formula: CnH2n+2
Simplest alkane: Methane, CH4
Carbon forms four single covalent bonds with four hydrogen atoms
Carbon atom attains an octet
Each hydrogen atom attains a duet
Methane molecule is stable
Figure on top is from page 143
Figure at the bottom is from page 143

9. Alkanes (continued) Example of larger alkanes
Figure on the left is from page 144
Figure on the right is from page 144

10. Polarity of Hydrocarbons
Carbon and hydrogen that compose methane have only slightly different electronegativities, making the bonds between them mostly nonpolar
Any slight polarity present in each bond is canceled by the tetrahedral shape of the molecule
Every other hydrocarbon is also nonpolar
Hydrocarbons are unable to mix with polar substances such as water

11. Structural Formulas Show the relative positions of atoms in a molecule
Two-dimensional
Similar to Lewis structures, but dashes represent bonding electron pairs

12. Structural Formulas (continued)
Condensed structural formulas are compactly written structural formulas
Example: Ethane (C2H6)
Figure is from page 144

13. Propane Formulas
Figure 6.5; page 144

14. Naming Alkanes
Straight-chain alkanes are named with a base name, reflecting the number of carbon atoms in the longest continuous chain and using the suffix -ane.
Table 6.2; page 146

15. Table 6.1: Alkanes
Table 6.1; page 145 15

16. Table 6.1: Alkanes (continued)
Table 6.1; page 145 16

17. Concept Check 6.1
Give the molecular, structural, and condensed formulas for the straight-chained alkanes with seven and eight carbons and name them.

18. Concept Check 6.1 Solution
C7H16: Heptane
C8H18: Octane

19. Properties of Alkanes Flammability Nonpolarity
CH3CH2CH3 + 5 O2 > 3 CO2 +4 H2O
Combustion reaction: Carbon-containing compound reacts with oxygen to form carbon dioxide and water
Nonpolarity
Table 6.3; page 147 19

20. Alkenes and Alkynes Unsaturated hydrocarbons
Contain at least one double or triple bond, respectively
Have fewer hydrogen atoms per carbon atom than alkanes

21. Alkenes Flammable and nonpolar like alkanes
Double bond makes them susceptible to the addition of other atoms
The name of an alkene is derived from the corresponding alkane by changing the -ane ending to -ene
Picture of bananas from page 149

22. Concept Check 6.2
Draw the structural formula for 1-hexene.

23. Concept Check 6.2 Solution
The “hex-” prefix indicates that there are six carbons.
The -ene ending indicates that it is an alkene (contains a carbon–carbon double bond).

24. Concept Check 6.2 Solution (continued)
“1” indicates the position where the double bond begins (on carbon #1), with the longest continuous carbon chain numbered from the end giving the double bond the lowest number.

25. Table 6.4: Alkenes
Table 6.4; page 148

26. Alkynes
Alkynes can be derived from alkenes by removing two additional hydrogen atoms from the two carbon atoms on either side of the double bond and placing a triple bond between them
Ethyne (acetylene) is used in welding torches
Most of the other alkynes are not commonly encountered directly except as minor components of gasoline

27. Table 6.5: Alkynes
Table 6.5; page 150

28. Concept Check 6.3
Draw the structural formula for 1-hexyne.

29. Concept Check 6.3 Solution
The “hex-” prefix indicates that there are six carbons.
The -yne ending indicates that it is an alkene (contains a carbon–carbon triple bond).
“1” indicates that the triple bond begins on carbon #1, with the longest continuous carbon chain numbered from the end giving the triple bond the lowest number.

30. Isomers
Molecules having the same molecular formula but different structures
Differ in their properties and can be distinguished by inspecting their structural formulas
Both the figures are from page 150

31. Isomers (continued 1)
Alkenes and alkynes exhibit isomerism based on the position of the double or triple bond
Example: Double bond in butane can be in two different positions
Figure is from page 151.

32. Isomers (continued 2)
Have radically different properties from each other
Nature can take the two atoms and make two different molecules with drastically different properties and functions
One of them, progesterone, makes pregnancy possible; the other, THC, alters the way the brain processes stimuli

33. International Union of Pure and Applied Chemistry (IUPAC) Recommendations for Naming Hydrocarbons
Alkanes
Determine the base name after selecting the longest continuous chain and counting the number of carbon atoms in it
Consider branches as substituents of the base chain
Number the base chain beginning with the end closest to the first branch and assign a number to each substituent

34. Write the name in the following order:
International Union of Pure and Applied Chemistry (IUPAC) Recommendations for Naming Hydrocarbons (continued)
Write the name in the following order:
Number of the substituent followed by a dash
Name of the substituent
Base name of the compound

35. Concept Check 6.4
Name the following alkane:

36. Concept Check 6.4 Solution
The longest continuous carbon chain has six carbons and is named hexane.
It is numbered from the end giving the substituent the lowest possible number.
Methyl substituent is located on carbon #3.
The compound is named 3-methylhexane.

37. Additional IUPAC Rules
When two or more substituents are present, number each and list them alphabetically
Use a numbering system that contains the lowest possible numbers
When two or more substituents are on the same carbon, use that number twice
Use prefixes to denote identical substituents, and separate the numbers indicating their positions from each other using a comma 37

38. Concept Check 6.5
Name the following alkane:

39. Concept Check 6.5 Solution
Heptane is the longest continuous carbon chain.
Two methyls and an ethyl are branching substituents.

40. Concept Check 6.5 Solution (continued)
Substituents are named 5-ethyl and 2,2-dimethyl according to their positions on the chain, then are listed alphabetically in the name.

41. Naming Alkenes and Alkynes
Named similar to alkanes, except for the addition of a number at the beginning to indicate the position of the multiple bonds and a change from -ane to -ene or -yne in the base name
The base chain is numbered to give the multiple bond the lowest possible number

42. Naming Alkenes and Alkynes (continued)
Name the following compounds:
1-butene
2-pentyne
4-methyl-2-pentene
5-ethyl-3-heptyne

43. Kekulé Early structure elucidation
Carbon’s tendency toward four bonds
Dreamed that he saw chains of six carbon atoms as snakes
One snake bit its own tail
Proposed benzene as a ring of six carbon atoms with alternating single and double bonds after being stimulated by his dream
Structure is still accepted today with a minor modification

44. Update on Kekulé’s Benzene Ring
Kekulé proposed a ring containing alternating double and single bonds
The bonds in benzene have the same length due to resonance
Each bond is now considered to be midway between a double and a single bond
Graphic from page 155

45. Update on Kekulé’s Benzene Ring (continued)
Structure of benzene is drawn as a hexagon with a circle inside it
Figure is from page 156.

46. The Benzene Ring
Particularly stable and is found in many organic molecules
When the ring contains substituents, it is called a phenyl ring
Also called aromatic ring because of the notable aroma of many compounds containing such a ring
Two or more such rings fused together make polycyclic aromatic hydrocarbons

47. Common Examples
Top and Bottom figures are from page 157

48. Functionalized Hydrocarbons
Basic hydrocarbon structures form the foundation of a major grouping of organic compounds known as functionalized hydrocarbons
Graphic from page 158

49. Functionalized Hydrocarbons (continued)
Contain additional atoms or groups of atoms called functional groups incorporated into their structure
Insertion of functional groups into a hydrocarbon alters its properties
Example of a functional group: —OH in ethanol
All compounds containing the same functional group form a family
Have characteristic properties associated with that functional group

50. Representing Functionality
Generic symbolism is R—FG, where R is the hydrocarbon part of the molecule and FG is the functional group
Symbol for alcohol is R—OH
Functional groups help organize and classify organic compounds in a systematic way

51. Table 6.6: Functionalized Hydrocarbons
Table 6.6; page 158

52. Concept Check 6.6
For the following compound, identify the functional group and the name of its family.

53. Concept Check 6.6 Solution
For the following compound, identify the functional group and the name of its family.

54. Chlorinated Hydrocarbons
Found in pesticides, solvents, and refrigerant liquids
Have one or more chlorine atoms substituting for one or more hydrogen atoms
Have the general formula R–Cl
Addition of chlorine to a hydrocarbon tends to lower its flammability and chemical reactivity
Figure 6.9, page 159

55. Dichlorodiphenyltrichloroethane (DDT)
Paul Muller demonstrated DDT’s effectiveness against insects and relative nontoxicity to humans
Dramatically decreased malaria cases in many countries
Muller was awarded Nobel Prize in 1948
Resistance and bioamplification led to DDT’s ban
The American bald eagle was placed on the endangered species list because of DDT. It has made a dramatic comeback since the ban on DDT.
Page 159

56. Chlorofluorocarbons (CFCs)
Considered a subfamily of chlorinated hydrocarbons and contains fluorine as well as chlorine
Chemically stable
Eventually drift to the upper atmosphere, where high-energy sunlight breaks a chemical bond and releases a reactive chlorine atom

57. Chlorofluorocarbons (CFCs) (continued)
Danger to the ozone layer led to the ban on the use of CFCs
Figure 6.10; page 160

58. Alcohols General formula: R-OH
Found in alcoholic beverages and in medical antiseptics
Presence of —OH causes alcohols to be polar
Named according to the name of the hydrocarbon chain modified to end in -ol
Figure is from page 161

59. Ethanol Alcohol present in alcoholic beverages Gasoline additive
Made by sugar fermentation
C6H12O6 → 2 CH3CH2OH + 2 CO2
All alcoholic beverages contain primarily ethanol and water, with a few other minor components
Central nervous system (CNS) depressant
Could pose adverse health effects
Graphic from page 160

60. Other Alcohols
Substitution of a methyl group for hydrogen in ethanol produces isopropyl alcohol
Known as rubbing alcohol
Figure is from page 161

61. Other Alcohols (continued)
Methanol, which is used as a solvent, is toxic to the human liver
Figure is from from page 162

62. Aldehydes and Ketones Commonly found in pleasant flavors and aromas
Aldehydes have the general formula RCHO, where the oxygen is joined to the carbon via a double bond
Figure is from page 163.

63. Aldehydes and Ketones (continued)
Ketones are similar to aldehydes, but instead of one R group, they have two
Have the general formula RCOR′
R' means that the second R group could be different from the first

64. Formulas
Aldehydes
Named according to the number of carbon atoms and given the ending -al
Methanal (formaldehyde) is the simplest aldehyde
Figure is from page 162

65. Formulas (continued) Ketones
Similar to aldehydes but have two R groups with carbonyl
Names end in -one
Acetone is the simplest ketone
Major component of fingernail polish remover
Graphic from page 162

66. Carboxylic Acids Commonly found in sour foods General formula: RCOOH
Simplest carboxylic acid is formic acid (HCOOH)
Figure is from page 165

67. Esters Have pleasant odors General formula: R—COO—R′
Named according to the relevant R and R′ groups and end with –ate
Figure is from page 167

68. Ethers Contain the functional group —O—
General formula: R—O—R′, where R and R′ are hydrocarbons
Named according to the two hydrocarbon groups and given the ending -ether
Simplest ether is dimethyl ether
Figure is from page 167

69. Amines Organic compounds that contain nitrogen General formula: NR3
Notable for unpleasant odors
Named according to R groups present and end in -amine
Figure is from page 168

70. Concept Check 6.7
Match each of the compounds with the following families: Ketone, aldehyde, ester, carboxylic acid, alcohol, and amine.

71. Concept Check 6.7 Solution
The functional groups are circled.

72. Chapter Summary Molecular concept Societal impact
Organic compounds versus inorganic
Organic compounds make everyday living possible
Hydrocarbons include alkanes, alkenes, and alkynes
Hydrocarbons are the primary molecules that society uses for fuel
Other functional groups
Organic functional groups can be recognized in the compounds that are used every day