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Alkanes and Aromatic Hydrocarbons

Organic Compounds

Bonding in Hydrocarbons

Naming Alkanes

Properties of Alkanes

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“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)

Depicting Formulas

– molecular formula C2H6

– structural formula

– condensed structural formula CH3 CH3

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Timberlake LecturePLUS 4

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

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Alkanes

Contain C and H only

Contain single bonds C-C

Have 4 bonds to every carbon (C) atom

Are nonpolar

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Complete Structural Formulas

Show the bonds between each of the atoms

H H

H C H H C H H H

CH4 , methane

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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

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IUPAC NamesName # carbons Structural Formula

Methane 1 CH4

Ethane 2 CH3CH3

Propane 3 CH3CH2CH3

Butane 4 CH3CH2CH2CH3

Pentane 5 CH3CH2CH2CH2CH3

IUPAC = The International Union of Pure and

Applied Chemistry

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IUPAC NAMES

Name # carbons Structural Formula

Hexane 6 CH3CH2CH2CH2CH2CH3

Heptane 7 CH3CH2CH2CH2CH2CH2CH3

Octane 8 CH3CH2CH2CH2CH2CH2CH2CH3

Nonane 9 CH3 CH2 CH2CH2CH2CH2CH2CH2CH3

Decane 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

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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?

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Solution Alk1

A. CH3CH2CH2CH3

B. C4H10

C. butane

Timberlake LecturePLUS 12

Reactions of Alkanes

Combustion

alkane + O2 CO2 + H2O + heat

Timberlake LecturePLUS 13

Combustion In the Cell

Metabolic oxidation is combustion

C6H12 O6 + 6O2 6CO2 + 6H2O + ATP + heat

glucose

Timberlake LecturePLUS 14

Learning Check Alk2

Complete the combustion reaction for

C3H8 + O2 +

Balance your equation

Timberlake LecturePLUS 15

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

Timberlake LecturePLUS 16

Learning Check Alk3

Complete and balance the reaction for the complete combustion of C7H16

Timberlake LecturePLUS 17

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