Do Now
Take out your worksheet (work in group first )
Objective
Doing the problems from the worksheet (for
going over the naming method)
Saturated compounds /Unsaturated compounds
Comparison between Alkane ;Alkene ;Alkyne
Isomers
Homework
P 719/43,44,45,48
Answer for worksheet
1.
2.
3.
4.
5.
6.
7.
2-methyl propane
2-ethyl propane
2-ethyl heptane
3-ethyl hexane
2,2,4-trimethyl Pentane
3-methyl-3-Hexyl Heptane
4-ethyl-6-methyl nonane
• Saturated compounds
• Concept : Organic compounds that contain the
maximum number of hydrogen atoms per carbon
atom
• Example : Alkanes
• Unsaturated compounds
• Concept : Compounds that contain double or
triple carbon-carbon bonds
• Example : Alkenes ;Alkynes
Guessing about bonds
Every bond means two atoms sharing two electrons together
• Alkanes
• The only bonds
in alkanes are
single covalent
bonds
• CnH2n+2
Ethane
Ethene
• Alkynes
• Hydrocarbons
that contain one
or more carboncarbon triple
covalent bonds.
• CnH2n-2
• Alkenes
• Hydrocarbons that
contain one or
more carboncarbon double
covalent bonds
• CnH2n
Ethyne
Name
Molecular structure
Boiling point (Casers)
Ethane
CH3--CH3
-88.5
Ethene
CH2== CH2
-103.9
C2
Ethyne
-81.8
C3
Propane
CH3CH2CH3
-42.0
Propene
CH3CH==CH2
-47.0
Propyne
-23.3
The introduction of a double or triple bond into a hydrocarbon does not
have a dramatic effect on physical properties such as boiling point. But the
double bonds is more stable ,so it needs more energy to break it apart.
Naming Alkene
To name an alkene by the IUUPAC system ,
find the longest chain in the molecule that
contains the double bond. This chain is the
parent alkene
It uses suffix –ene .
The chain is numbered so that the carbon
atoms of the double bond have the lowest
possible number
Substituents on the chain are named and
numbered in the same way they are for the
alkanes.
Draw ,name all the alkenes with the molecular formula
C4H8
Identify and name the alkanes ; alkenes ;alkynes
C 4 H8
Alkene
Butene
C 5 H8
Alkyne
Pentyne
C 3 H8
Alkane
Propane
C 3 H6
Alkene
Propene
C6H10
Alkyne
Hexyne
C4H10
Alkane
Butane
Tell which is saturated and unsaturated
C 4 H8
C 3 H8
C6H10

C 5 H8

C 3 H6
C4H10

Alkanes are saturated compounds .
Because the only bonds in it are single covalent bonds.
• Isomers-- Compounds that have the same
molecular formula but different molecular
structures
• Structural isomers
• Stereoisomers
• Geometric Isomers
• Optical Isomers
Isomers
Structural
Isomers
Stereoisomers
Geometric
Isomers
Optical Isomers
Structural Isomers:
• same molecular formula , different order.
• differ in physical properties. different chemical
relativities.
Stereoisomers
• Molecules in which the atoms are joined in the same
order, but the positions of the atoms in space are
different.
• Two types : Geometric Isomers and optical Isomers
Geometric Isomers have atoms joined in the same order
, but differ in the orientation of groups around a double
bond.
Optical Isomers are that pairs of molecules that differ only
in the way that four different groups are arranged around a
central carbon atom .
Geometric Isomers same order , differ in the orientation
of groups around a double bond.
Trans Configuration
The methyl groups are on opposite sides of the
double bond
Cis Configuration
The methyl groups are on the same side of the
double bond
Optical Isomers are that pairs of molecules that differ
only in the way that four different groups are arranged
around a central carbon atom .
Asymmetric carbon is a carbon with four different atoms
or groups attached
Draw a structure formula or carbon skeleton for each of the following
alkenes .If cis and trans forms are present ,include both forms.
a.2-pentene
b.2-methy-2-pentene
c.3-ethyl-2-pentene
Draw one structural isomer of each compound
P 719/43,44,45,48