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. Alkanes or Paraffins
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 ”

4. 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)

5. 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…

6. Structural Isomers of C4H10
2-methylpropane or

7. 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!

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

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

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

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

12. 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

13. Structural Isomers What are the possible structural isomers of C3H7Br?
1-bromopropane
2-bromopropane
What are the possible structural isomers of C4H9Cl?
1-chlorobutane
2-chloro-2-methylpropane
2-chlorobutane
1-chloro-2-methylpropane

14. Structural Isomer Practice
On piece of your own paper, draw AND name ALL of the isomers with the following formulas:
Formulas
# isomers
C4H9I
C3H6Cl2
C5H11Br
C4H8Cl2 4 8 9
To be honest, there may be more…this is what I found, so try and prove me wrong! Extra Credit to anyone who can find more structures…
Some of your drawings may look different, but they are only different structures (isomers) if they also have different names

15. Structural Isomers: C4H9I
1-iodobutane
2-iodobutane I I
2-iodo-2-methylbutane
1-iodo-2-methylbutane

16. Structural Isomers: C3H6Cl2
1,1-dichloropropane
1,2-dichloropropane
1,3-dichloropropane
2,2-dichloropropane

17. Structural Isomers: C5H11Br
1-bromopentane
2-bromopentane
3-bromopentane
1-bromo-3-methylpentane

18. Structural Isomers: C5H11Br
1-bromo-2-methylbutane
2-bromo-3-methylbutane
1-bromo-2,2-dimethylbutane
2-bromo-2-methylbutane

19. Structural Isomers: C4H8Cl2
1,1-dichlorobutane
1,2-dichlorobutane
1,3-dichlorobutane
1,4-dichlorobutane

20. Structural Isomers: C4H8Cl2
1,1-dichlorobutane
1,2-dichloro-2-methylpropane
2,2-dichlorobutane
1,3-dichloro-2-methylpropane
2,3-dichlorobutane