1. ORGANIC CHEMISTRY

2. ORGANIC CHEMISTRY
-Organic molecules
contain only C, H, O, N
and sometimes S and P
-56 204 570 organic
substances have been
recorded

3. ORGANIC CHEMISTRY
What allows for the diversity of organic compounds?
-Carbon can make 4 bonds
-The 4 bonds can be a combination of single, double,
and triple bonds
methane, CH4 methanal, CH2O
ethanenitrile, CH3CN

4. ORGANIC CHEMISTRY
Hydrocarbons:
When an organic molecule is composed only of hydrogen and
carbon, it is called a hydrocarbon:
Alkanes: Hydrocarbons with single bonds
Alkenes: Hydrocarbons with double bond(s)
Alkynes: Hydrocarbons with triple bond(s)

5. ALKANES

6. ALKANES
-Characterized by C-C single bonds
-Also known as saturated hydrocarbons
-empirical formula = CnH2n+2
 CnH2n+2, n=8
= C8H18

7. ALKANES
Properties:
-Hydrophobic (does not mix with water and other polar
substances)
-Generally low boiling points (due to weak London Dispersion
Forces)
- Longer alkane molecules have higher boiling points

8. ALKANES
Some IUPAC* names of alkanes:
ethane propane butane
All alkanes have the suffix “ane”
*International Union of Pure and Applied Chemistry

9. ALKANES
IUPAC naming system:
Each alkane also has a prefix based on the number of
carbon atoms: meth = 1
eth = 2
prop = 3
but = 4
pent = 5
hex = 6
hept = 7
oct = 8
non = 9
dec = 10
undec = 11
dodec = 12

10. ALKANES
IUPAC naming system:
Molecular
formula Condensed Structural Formula Name
CH4 CH4 methane
C2H6 CH3CH3 ethane
C3H8 CH3CH2CH3 propane
C4H10 CH3CH2CH2CH3 butane
C5H12 CH3CH2CH2CH2CH3 pentane
C6H14 CH3CH2CH2CH2CH2CH3 hexane
C7H16 CH3CH2CH2CH2CH2CH2CH3 heptane
C8H18 CH3CH2CH2CH2CH2CH2CH2CH3 octane
C9H20 CH3CH2CH2CH2CH2CH2CH2CH2CH3 nonane
C10H22 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3 decane

11. ALKANES
IUPAC naming system:
prefix suffix
family
Number of
carbons in the
longest chain
Ex: methane

12. ALKANES
IUPAC naming system:
Name the following alkanes:
hexane nonane

13. ALKANES
IUPAC naming system:
Not all alkanes are straight chains. Some alkanes
have alkyl side groups (alkyl substituents) attached.
-CH3 methyl
Ex:
-C2H5 ethyl
methyl group
-C3H7 propyl
-C4H9 butyl
-C5H11 pentyl
-C6H13 hexyl
-C7H15 heptyl
-C8H17 octyl
name: methylbutane

14. ALKANES
IUPAC naming system:
For alkanes with side groups…
Substituent(s) prefix suffix
family
Side groups Number of
carbons in the
longest chain
Ex: methylbutane

15. ALKANES
IUPAC naming system:
Name the following branched alkanes
1 2 3 4 5 1 2 3 4 5
2-methylpentane 3-methylpentane
When there is ambiguity, the substituent
must be numbered according to the carbon
atom that it is attached to
(aim to get the lowest possible number)

16. ALKANES
IUPAC naming system:
Which name is incorrect?
1 2 3 4 5 5 4 3 2 1
2-methylpentane 4-methylpentane
Aim for the lowest possible
number when counting

17. ALKANES
IUPAC naming system:
Name the following branched alkanes
1 2 3 4 5
1 2 3 4 5 6
2,3-dimethylhexane 3-ethylpentane

18. ALKANES
IUPAC naming system:
Name the following branched alkane
4 5
1. Find the longest
continuous chain
CH3 - CH - CH3
of C atoms
1 2 3|
(parent chain)
CH3 - CH - CH2
2. Identify any |
substitutents
CH3
2,4 -dimethylpentane

19. ALKANES
IUPAC naming system:
Name the following branched alkane
3 4 5 6
2 7
The order of
substituents in the 1 8
name is based on
alphabetical order
9
4,5,5-triethyl-3,6,6-trimethylnonane

20. ALKANES
Drawing alkanes:
3 types of diagrams
Structural diagram
Condensed diagram CH3CH2CH2CH2CH2CH3
Line diagram

21. ALKANES
Drawing alkanes:
Line diagrams:
2 4 6
1 3 5
Every end or point on a line diagram
represents a carbon atom. Hydrogen
atoms are not shown.

22. ALKANES
Drawing alkanes:
Draw the following alkanes using line diagrams
methylbutane 3-ethyl-3,4-dimethylheptane
2 4 2 4 6
1 3 1 3 5 7

23. ALKANES
When two possible names exist:
3-ethyl-5-methylheptane or 5-ethyl-3-methylheptane?
The ethyl has priority (and gets the lower number)
because it comes before methyl in the alphabet.

24. ALKANES
Homework:
Page 17
5) a, d, f
6) a, b
7) a, b
9) c

25. CYCLOALKANES

26. CYCLOALKANES
-Ring-like structures of alkanes
-empirical formula = CnH2n
 CnH2n, n=6
= C6H12

27. CYCLOALKANES
IUPAC naming system:
Name the following alkanes:
cyclobutane cyclooctane cyclopentane
The prefix “cyclo” is added to the alkane name

28. CYCLOALKANES
IUPAC naming system:
Name the following alkanes:
CH3CH2CH2
2 3
CH2 CH
1 4
6 5
CH2 CH2
4-ethyl-1,1,2-trimethylcyclohexane
methylcyclohexane propylcyclobutane

29. CYCLOALKANES
IUPAC naming system:
Draw the following alkanes using line structures:
1,1-dipropylcyclopropane 1-ethyl-1,2,5-trimethylcyclopentane

30. CYCLOALKANES
IUPAC naming system:
Which name is correct?
1-ethyl-1,2,5-trimethylcyclopentane
vs.
2-ethyl-1,2,3-trimethylcyclopentane
When two different substituents (ex. ethyl and methyl) can be
assigned the same number, then the group that comes first in
the alphabet gets the lowest number.

31. HALOALKANES

32. HALOALKANES
-Alkanes with halogen atoms
-Also known as alkyl halides

33. HALOALKANES
IUPAC naming system:
Halogen groups: -F fluoro
-Cl chloro
-Br bromo
-I iodo
Just like alkyl substituents, the halogens are placed at the
beginning of the name, and are ordered alphabetically.

34. HALOALKANES
IUPAC naming system:
Name the following haloalkanes:
1,2-dibromo-1-chlorobutane
2-bromo-2-methylpropane
2-bromo-2-chloro-1,1,1-trifluoroethane

35. STRUCTURAL ISOMERS

36. STRUCTURAL ISOMERS
Compounds with the same molecular formula
but with different bonding arrangements are
structural isomers.
Butane isomers Pentane isomers

37. STRUCTURAL ISOMERS
Ex: Structural isomers of hexane + boiling points
Changing the structure affects the boiling point
This structure can easily stack and form more London Dispersion Forces
with neighbouring hexane molecules

38. STRUCTURAL ISOMERS
Draw all of the structural isomers of heptane using
line structures:

39. STRUCTURAL ISOMERS
The longer the chain, the greater the number of
structural isomers
Number of Carbon Atoms Number of Isomers
4 2
5 3
6 5
7 9
8 18
9 35
10 75
12 355
15 4347