Download Organic Chemistry

Organic Chemistry
“The most important hypothesis in all of
biology…is that everything that animals do,
atoms do. In other words, there is nothing
that living things do that cannot be
understood from the point of view that
they are made of atoms acting according
to the laws of physics.”
Richard Feynman (1918-1988)
Organic Chemistry and Hydrocarbons
 “Organic” originally referred to any
chemicals that came from organisms
 1828 - German chemist Friedrich Wohler
synthesized urea in a lab
 Today, organic chemistry is the chemistry of
virtually all compounds containing the
element carbon
Allotropes of carbon
Carbon exists naturally in three forms:
 Graphite
 Diamonds
 Fullerenes
Organic Chemistry and Hydrocarbons
 Over a million organic compounds,
with a dazzling array of properties
 Why so many? Carbon’s unique
bonding ability!
Organic Compounds
Contain carbon
Have covalent bonds
Have low melting points
Have low boiling points
Burn in air (oxygen)
Are soluble in nonpolar solvents
Form large molecules
Alkanes
 Contain C and H only
 Contain single bonds
C-C
 Have 4 bonds to every carbon (C) atom
 Are nonpolar
Straight chain alkanes:
 Contain any number of carbons atoms, one after the
other, in a chain. Each carbon atoms is bonded to 1 or
2 other carbon atoms.
Complete Structural Formulas
Show the bonds between each of the atoms
H
H

H
CH
H C H

H
H
CH4 , methane
More Alkanes
H
H C
H
H
Condensed Structural Formulas
C H
H
CH3 CH3
Ethane
H H H
H
C C C H
H
H H
CH3 CH2 CH3
Propane
IUPAC Names
Name
# carbons
Structural Formula
Methane
1
CH4
Ethane
2
CH3CH3
Propane
3
CH3CH2CH3
Butane
4
CH3CH2CH2CH3
Pentane
5
CH3CH2CH2CH2CH3
IUPAC NAMES
Name # carbons
Structural Formula
Hexane 6
CH3CH2CH2CH2CH2CH3
Heptane 7
CH3CH2CH2CH2CH2CH2CH3
Octane 8
CH3CH2CH2CH2CH2CH2CH2CH3
Nonane 9
CH3 CH2 CH2CH2CH2CH2CH2CH2CH3
Decane 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3
Learning Check Alk1
A. What is the condensed formula for
H H H H
H
C C C C
H
H H H H
B. What is its molecular formula?
C. What is its name?
Solution Alk1
A.
CH3CH2CH2CH3
B.
C4H10
C.
butane
Reactions of Alkanes
Combustion
alkane + O2
CO2 + H2O + heat
Combustion In the Cell
Metabolic oxidation is combustion
C6H12 O6 + 6O2
glucose
6CO2 + 6H2O + heat
Learning Check Alk2
Complete the combustion reaction for
C3H8 + O2
Balance your equation
+
Solution Alk2
Step 1
C3H8 + O2
CO2 + H2O
Step 2
C3H8 + O2
3 CO2 + 4 H2O
Step 3
C3H8 + 5 O2
3 CO2 + 4 H2O
Learning Check Alk3
Complete and balance the reaction for the
complete combustion of C7H16
Solution Alk3
Step 1
C7H16 + O2
CO2 + H2O
Step 2
C7H16 + O2
7 CO2 + 8 H2O
Step 3
C7H16 + 11 O2
7 CO2 + 8 H2O
Branched chain alkanes:
 Occur when a carbon atoms bonds with three or four
carbon atoms.
Branched chain alkanes:
 Substituents: take place of a hydrogen atom on a
parent hydrocarbon.
substituent
c
c
c
Parent alkane
(propane)
c
c c c
c c c c c c
Parent alkane
(hexane)
Hydrocarbon substituents
 Are called alkyl group
 Name ending with –yl
 Methyl group (CH3-)
 Ethyl group (CH3CH2-)
 Propyl group (CH3CH2CH2-)
Rules for naming branched alkanes
Find the longest chain of carbons in the molecule or
parent chain. (not necessarily a straight line)
2. Number the carbons in parent chain. Start at the end
that will give the groups attached to the chain the
smallest numbers.
3. Identify with numbers the positions of the
substituents on the chain.
1.
4. Use prefixes to indicate the appearance of the same
group more than once: di- (twice), tri- (three times)
5. List the names of the substituents groups in
alphabetical order.
6. Commas separate numbers, hyphens separate
numbers and words. Name is written without spaces
Ex. 1 Name the following alkane:
1
2
3
4
CH3
CH2
CH
CH3
4
3
2
CH3
1. Choose
parent chain
and name it
1
2- methyl (located in carbon 2)
3. Identify position of
substituent group and
name it.
5. List substituent
groups in alphabetical
order.
2. Number parent
chain in a way that
substituents have
smallest numbers.
4. Not applicable
6. Separate letters and
numbers with hyphen
2-methyl butane
Ex.2
CH3 CH CH2 CH2 CH3
CH2
CH3
Ex.2
CH3 CH CH2 CH2 CH3
CH2
CH3
 Parent alkane
 Does not have to be a straight line, only longest chain.
 Name of parent alkane:
hexane
3
Ex.2
4
5
6
CH3 CH CH2 CH2 CH3
2 CH2
1 CH3
 Number Parent alkane
 Number in way that substituent group has smallest
number.
 Name and position of substituent group: 3-methyl
3
Ex.2
4
5
6
CH3 CH CH2 CH2 CH3
2 CH2
1 CH3
 Name of organic compound
 3-methylhexane
Cw p 226 #1
Writing structural formulas:
Write the complete structural formula for
2,2-dimethylpropane
1.
Writing structural formulas:
Write the complete structural formula for
2,2-dimethylpropane
1.
Write only the carbons first. Start with the parent
alkane.
2,2-dimethylpropane
C
C
C
Writing structural formulas:
Write the complete structural formula for
2,2-dimethylpropane
1.
Number the parent alkane from left to right.
C
C
C
1
2
3
Writing structural formulas:
Write the complete structural formula for
2,2-dimethylpropane
1.
Identify the substituent groups and their position:
2,2-dimethylpropane
There are two (di) methyl groups (CH3-) in carbon #2
C
CH3
C
C
1
2
3
CH3
Writing structural formulas:
Write the complete structural formula for
2,2-dimethylpropane
1.
Add the necessary hydrogen bonds so that each carbon
has a maximum of 4 bonds.
H
H C
H
CH3
C
CH3
H
C H
H
Classwork p226 #2,3
Isomers
 Are compounds that have the same molecular formula
but different structural formulas.
 Have different physical properties, like boiling point
and melting point and different chemical reactivities.
 Ex. C4H10
CH3 CH2 CH2 CH3
butane
CH3 CH CH3
CH3
2-methylpropane
Classwork
 Draw and name the isomers for the organic
compounds with the following molecular formulas:
a)C5H12 (3 different structures)
b) C6H14 (5 different structures)