1. 21/10/99
Organic Chemistry The study of carbon compounds. Over 10 million compounds naturally exist More than are synthesized

2. Inorganic vs Organic Hydrocarbons containing CxHy
oxides of carbon (CO2, CO)
carbonates,bicarbonates (NaHCO3,CaCO3)
cyanides (NaCN, etc)
any carbon attached to a metal and no H
Hydrocarbons containing CxHy

3. Origin of organic compounds
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Origin of organic compounds
Originally from “organic” meaning life
Not just chemistry of life, chemistry of carbon
Naturally occurring organic compounds are found in plants, animals, and fossil fuels
All of these rely on the “fixing” of C from CO2
Synthetic organic compounds are derived from fossil fuels or plant material

4. The diversity of carbon compounds is based on the fact carbon atoms Form 4 Bonds
Forms strong covalent and nonpolar bonds with itself and other elements
Review:
Lewis Structure, Structural formula, Line diagrams

5. Carbon molecules form complex 3-D shapes
Common Molecular Shapes
Tetrahedral
Trigonal planar
Linear
Angular
Trigonal pyramidal

6. Simplest Hydrocarbons
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Simplest Hydrocarbons
Alkanes
C C
Alkenes
C C
Alkynes
C C
Aromatics

8. Naming Hydrocarbons (nomenclature)

9. Naming: common vs. IUPAC
Common names used in the 1800’s are still used for some compounds today: eg.
Commonly known as Acetylene
IUPAC: Ethyne
The International Union of Pure and Applied Chemistry (IUPAC) was established in 1900s
Systematic method allows an infinite number of compounds to be named given a few rules

10. Mnemonic for first four prefixes
Monkeys
Eat
Peeled
Bananas
First four prefixes
Meth-
Eth-
Prop-
But-

11. ? Other prefixes Decade Decimal Decathalon Pent- Oct- Dec-
Hex-, Hept-, Non-

12. Alkanes Are straight or branched-chain containing only single bonds
Are a homologous series –a group of compounds whose members differ by the addition of the same structural group
Named by using prefix and ending -ane

13. TASK
Write chemical and structural formula for all alkanes that contain up to 10 carbons
Methane CH4
Ethane CH3CH3
Propane CH3CH2CH3
Butane CH3CH2CH2CH3
Pentane
Hexane
Heptane
Octane
Nonane
Decane
This is just the beginning…………………………………………………………….. You may have noticed that branching creates enormous variation

14. 21/10/99
Try Naming These

15. Structural Isomers
Substances with the same chemical formula by different arrangements of atoms
Eg Butane & 2 methyl-propane
***Isomers have different physical and chemical properties

16. TASK: Draw all the isomers for pentane and hexane
Did you know?
3 isomers of pentane
5 isomers of hexane
Heptane-9
Octane-18
Nonane-35
Decane-75
making a total of 150 different possible alkane compounds containing 10 carbons.

17. Cyclic structures are circular Have “cyclo” in name
Greater complexity exists because organic compounds can form Cyclic (ring) structures?
Cyclic structures are circular
Have “cyclo” in name
Eg. Cyclopropane Cyclopentane

18. TASK Study the following graphic. What 2 trends can be identified?
Hypothesize why these trends exist.
TASK 2: Compare, contrast and explain the physical properties of the first 10 alkanes

19. Background: formulas for HxCy
CH single bonds Alkanes= CnH2n+2,
CH with one double bond Alkenes= CnH2n,
CH with two double bonds Alkynes= CnH2n-2
Q - How many hydrogens in each of these:
Alkane C6H
Alkene C22H

20. Basic names of hydrocarbons
Hydrocarbon names are based on:
1) class
2) # of C,
3) side chain type
4) position
Q - What names would be given to these:
7C, 9C alkane
2C, 4C alkyne
1C, 3C alkene
heptane, nonane
ethyne, butyne
does not exist, propene

21. Numbering carbons 1-pentene Q- draw pentene A- Where’s the bond?
We number C atoms
Always start numbering for the carbon nearest the double bond the lowest number
Q - Name these
C2H4
2-butene
Ethene
3-nonyne

22. Multiple multiple bonds
2,3-heptadiene
2,4,6-nonatriyne
Rules
Give 1st bond lowest #
include di, tri, tetra, penta, etc. before ene/yne
Comma between #s, hyphen between #-letter
CH3CH2CH2CH=C=CH2
2-butyne
1,2,4-pentatriene
1,2-hexadiene

23. Cyclic structures Q- Draw these:
cyclobutene 1,3-cyclopentadiene cyclopropane

24. Naming side chains Names are made up of: side chains, root3
Names are made up of: side chains, root
2,3-dimethylpentane
Root is the longest possible HC chain
Must contain multiple bonds if present
Add -yl to get name of side chain
Common side chains include:
CH3- methyl CH3CH2- ethyl
CH3CH2CH2- propyl (CH3)2CH- isopropyl

25. Naming side chains
Example: use the rules on the bottom of handout to name the following structure
Rule 1: choose the correct ending
ene

26. Naming side chains
Rule 2: longest carbon chain
ene

27. Naming side chains Rule 3: attach prefix (according to # of C) ene
1-hexene

28. Naming side chains
Rule 4: Assign numbers to each carbon
1-hexene

29. Naming side chains Rule 4: Assign numbers to each carbon 1-hexene

30. Naming side chains Rule 5: Determine name for side chains 1-hexene
ethyl
methyl
methyl
Rule 5: Determine name for side chains
1-hexene
1-hexene

31. Naming side chains Rule 6: attach name of branches
ethyl
methyl
methyl
Rule 6: attach name of branches
2-ethyl-4-methyl-4-methyl-1-hexene
1-hexene

32. Naming side chains Rule 7: list alphabetically
ethyl
methyl
methyl
Rule 7: list alphabetically
2-ethyl-4-methyl-4-methyl-1-hexene
1-hexene

33. Naming side chains Rule 8,9: group similar branches
ethyl
methyl
methyl
Rule 8,9: group similar branches
2-ethyl-4-methyl-4-methyl-1-hexene
1-hexene

34. Naming side chains Rule 8,9: group similar branches
ethyl
methyl
methyl
Rule 8,9: group similar branches
2-ethyl-4,4-dimethyl-1-hexene

35. Try Naming Side Chains 3-methylhexane 4-ethyl-2,3-dimethylheptane
5-ethyl-2,4,6-trimethyloctane

36. Naming side chains Name the structures below 3-ethyl-2-methylpentane
3-ethyl-1,5,5-trimethylcyclohexene

37. Try Drawing These 2,2-dimethyloctane 1,3-dimethylcyclopentane
1,1-diethylcyclohexane
6-ethyl-5-isopropyl-7-methyl-1-octene

38. 21/10/99
Try Naming

39. Aromatic Hydrocarbons
Aromatic compounds contain benzene ring structures and their derivatives.
Benzene (C6H6)
most commonly used organic (nonpolar) solvent
very stable substance, unreactive
toxic if inhaled -carcinogenic
produced by processing coal, crude oil, gasoline or the combustion of rubber tires
if it occurs as a side chain it is called a phenyl group

40. Resonance
The properties of this compound can be explained by following theory:
-the chemical bonds between carbon atoms are not single or double
-all bonds between carbons in the benzene ring are identical in length and strength
-there is an even distribution of valence electrons around the entire molecule.
The resonance of the single and double bonds accounts for the stability of aromatic compounds.
This is illustrated by resonance structures:

41. Aromatic nomenclature
There are 2 naming methods
Numbering carbons
ortho, meta, para (stomp)
1,2-dimethylbenzene
orthodimethylbenzene ST
Ortho
Meta
1,3-dimethylbenzene
metadimethylbenzene
Para
1,4-dimethylbenzene
paradimethylbenzene