1. Organic Chemistry Organic Chemistry: The chemistry of carbon
and carbon-based compounds
Organic Chemistry in everyday life:
Smells & tastes: fruits, chocolate, fish, mint
Medications: Aspirin, Tylenol, Decongestants, Sedatives
Addictive substances: Caffeine, Nicotine, Alcohol, Narcotics
Hormones/Neurotransmitters: Adrenaline, Epinephrine
Food/Nutrients: Carbohydrates, Protein, Fat, Vitamins
Genetics: DNA, RNA
Consumer products: Plastics, Nylon, Rayon, Polyester

2. Drawing Organic Structures
Shortcuts make structures easier & faster to draw
Butane: C4H10
Lewis Structure
Carbon Atoms
Line Structure
Only shows bonds
C atoms assumed at each end and intersection of bonds
H atoms not shown
Assume 4 bonds to each C
Fulfill C’s 4 bonds by adding H’s
Condensed Structures
CH3CH2CH2CH3
CH3(CH2)2CH3

3. Types of Organic Compounds
Classified according to functional group
Alkane
Alkene
Alkyne
Haloalkane
Alcohol
Ether
Ketone
Aldehyde
Carboxylic acid
Amine
Amino acid
Amide

4. Big Idea in Organic Chemistry
Structure controls Function
Each functional group has predictable reactivity

5. Alkanes
All C atoms are tetrahedral and sp3 hybridized (only C-C single bonds)
General formula = CnH2n+2 (CH4, C2H6, C3H8, C4H10, etc.)
Can have linear or branched alkanes
C5H12 1° 3° 2°
Same molecular formula, different structure: structural isomers
Branches are called substituents
Primary (1°) carbon atom: bound to one other C atom
Secondary (2°) C atom: bound to 2 other C atoms
Tertiary (3°) C atom: ” 3 ”
Quaternary (4°) C atom: ” 4 ”

6. Names of Linear Alkanes and Alkyl Substituents
C atoms
Alkane
Alkyl substituents 1 2 3 4 5 6 7 8 9 10
CH4
CH3CH3
CH3CH2CH3
CH3CH2CH2CH3
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
-CH3
-CH2CH3
-CH2CH2CH3
Methyl
Ethyl
Propyl
etc.
Root: number of C atoms
Suffix: functional group
(-ane for alkanes)
(-yl for alkyl groups)

7. Naming Branched Alkanes (IUPAC)
Octane
4-ethyl 6 2 8
4-ethyl-3,5-dimethyloctane 5 4 7 3 1
3-methyl and 5-methyl
= 3,5-dimethyl
Root name: name of longest continuous C chain (parent chain)
2 equally long? Choose the one with more branches
Number C atoms in chain, starting at end with first branch
Identify substituents, give each a number (C it is connected to)
Two or more identical substituents: use prefixes (di-, tri-, tetra-, etc.)
List substituents alphabetically after prefix
Do not alphabetize prefixes
Punctuation: commas separate numbers from each other
hyphens separate numbers from names
no space between last substituent & root name

8. H C C H
Methane
CH4
Butane
C4H10 H C ? C H ? R R
Methyl
-CH3
Butyl
-C4H9
Where R = any other C atom or arrangement of C atoms

9. Naming Practice C H 2 - methylbutane butane Expanded Structure
Line Structure H C
2 - methylbutane
butane

10. Naming Practice H H CH3 H C C C H H C H H C H H C H H 4,4-dimethyl
Line Structure 1 2 3 4 5 6 4 5 6 H H C H H C H H C H H
4,4-dimethyl
hexane
3,3-dimethyl
hexane
Lowest sum of numbers
is correct

11. Isomers
The fat dog shook himself, and then rolled over on the wet rug. OR
The dog shook the fat rug, then rolled over and wet on himself.
These two statements use the same words...
but have very different meanings!
Likewise, isomers may have the same formula, but have very different structures…

12. Structural Isomers of C4H10
2-methylpropane or

13. Structural Isomer Practice
On piece of your own paper, draw AND name ALL of the isomers for the following alkanes:
Formulas
# isomers
Pentane
Hexane
Heptane
C5H12
C6H14
C7H16 3 5 9
Some of your drawings may look different, but they are only different structures (isomers) if they also have different names
If you complete that, try to draw and name all of the isomers for octane (C8H18). There are 18 of them!

14. Structural Isomers: Pentane (C5H12)
2-methylbutane
2,2-dimethylpropane

15. Structural Isomers: Hexane (C6H14)
2,3-dimethylbutane
2-methylpentane
2,2-dimethylbutane
3-methylpentane

16. Structural Isomers: Heptane (C7H16)
2,2-dimethylpentane
2-methylhexane
2,3-dimethylpentane
3-methylhexane

17. Structural Isomers: Heptane (C7H16)
2,4-dimethylpentane
3-ethylpentane
3,3-dimethylpentane
2,2,3-trimethylbutane

18. Comparing Structural Isomers
(Same formula, different structure)
C5H12
Structure
Name
Boiling point (°C)
pentane
36.0
2-methylbutane
27.9
2,2-dimethylpropane
9.5
More branching → weaker London dispersion forces
BP/MP of Linear alkanes > BP/MP of branched alkanes

19. First Ten Hydrocarbons: Properties
Number of
Carbon Atoms
Molecular
Formula
Melting
Point, oC
Boiling
Point, oC
# of
Isomers
Name
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane 1 2 3 4 5 6 7 8 9 10
CH4
C2H6
C3H8
C4H10
C5H12
C6H14
C7H16
C8H18
C9H20
C10H22
-182.5
-183.2
-187.7
-138.3
-129.7
95.3
90.6
56.8
53.6
29.7
-161.5
-88.6
-42.1
-0.5
36.1
68.7
98.4
125.7
150.8
174.0 1 2 3 5 9 18 35 75

20. First Ten Hydrocarbons: Properties
As number of carbons increases,
The boiling point increases
The melting point increases
The number of isomers increases

21. Nonpolar → only London Dispersion Forces
Properties of Alkanes
Nonpolar → only London Dispersion Forces
Larger molecular weight → Stronger London dispersion forces
Compound
Methane
Ethane
Propane
Butane
Pentane
Formula
CH4
C2H6
C3H8
C4H10
C5H12 MW 16 30 44 58 72
Boiling point (°C)
-164
-88.6
-42.1
-0.5
+36.0
Linear Alkanes:
1 - 4 C atoms: gas at room temp
C atoms: liquid at room temp
>15 C atoms: solid at room temp

22. Fractional Distillation of Crude Oil
Kelter, Carr, Scott, Chemistry A World of Choices 1999, page 429

23. Cycloalkanes Alkanes with closed ring(s) of C atoms
General formula: CnH2n (C3H6, C4H8, C5H10, etc.)
Naming: use cyclo- prefix before alkane name
cyclopropane
n = 3
cyclobutane
n = 4
cyclopentane
n = 5
cyclohexane
n = 6
C3H6
C4H8
C5H10
C6H12
Not Stable
Not Stable
Not Stable
Stable!!!
Angles of the bonds need to be near 108 degrees and the first 3 do not have that.

24. Nomenclature of Cycloalkanes
Find the longest carbon chain
If it is in the cycloalkane – use it as the base name
If it is in a straight chain, the cycloalkane becomes an alkyl group
1-cyclopropylpentane
Name the alkyl groups coming off of the cycloalkane
If there is only one, numbering is not needed
If there are 2 or more alkyl groups
Place the highest alphabetical alkyl group on the 1st carbon then followed by the others.
In numbering the carbons, you want the sum of the numbers to be the least possible.

25. Nomenclature of Cycloalkanes
Examples:

26. Nomenclature of Cycloalkanes
Examples

27. Nomenclature of Cycloalkanes
Examples

28. Nomenclature of Cycloalkanes
Examples

29. Nomenclature of Cycloalkanes
Examples

30. Chemical Bingo: Naming Review
There are 28 structures or names drawn on the next slide. Select 24 of them to be placed on your bingo card. (free space)
Because of space issues, I would number each bingo square and then list the names or structures on a separate sheet of paper
If I give you a name, you must match it to a structure. If I give you a structure, you must match it to a name

31. Chemical Bingo: Alkanes
isopropyl sec-butyl
tert-butyl isobutyl
decane nonane
2,3,4,5-tetramethylhexane
3,4-diethylhexane
3,5-diethyl-4-isopropylheptane
4-tert-butyl-3,5-dimethylheptane
4-ethyl-2,2,3,5,6,6-hexamethylheptane
Any isomer of C5H12
Any isomer of C6H14
Any isomer of C7H16

32. 16. ethane
17. cycloheptane
18. decane
19. 2,3,4,5-tetramethylhexane
20. 3,4-diethylhexane
21. 3,5-diethyl-4-propylheptane
22. 3,5-dimethyl-4-propylheptane
23. 4-ethyl-2,2,3,5,6,6-hexamethylheptane
24. 1-chloro-2-iodobutane
25. 1,2-diethylcyclohexane
26. 2-iodo-3,4-dimethylnonane
27. 3,3-diethyloctane
28. pentane