Alkanes and Aromatic Hydrocarbons

Organic CompoundsBonding in Hydrocarbons

Naming AlkanesProperties of Alkanes

“The most important hypothesis in all ofbiology…is that everything that animals do,atoms do. In other words, there is nothingthat 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 CompoundsContain carbonHave covalent bondsHave low melting pointsHave low boiling pointsBurn in air (oxygen) Are soluble in nonpolar solventsForm large molecules

Alkanes

Contain C and H only

Contain single bonds C-C

Have 4 bonds to every carbon (C) atom

Are nonpolar

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 Condensed Structural Formulas

H C C H CH3 CH3

H H Ethane

H H H

H C C C H CH3 CH2 CH3

H H H Propane

IUPAC NamesName # 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

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

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 6CO2 + 6H2O + heat

glucose

Learning Check

Complete the combustion reaction for

C3H8 + O2 +

Balance your equation

Solution

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

Complete and balance the reaction for the complete combustion of C7H16

Solution

Step 1

C7H16 + O2 CO2 + H2O

Step 2

C7H16 + O2 7 CO2 + 8 H2O

Step 3

C7H16 + 11 O2 7 CO2 + 8 H2O