Alkanes and Aromatic Hydrocarbons

1
Alkanes and Aromatic Hydrocarbons

• Organic Compounds
• Bonding in Hydrocarbons
• Naming Alkanes
• Properties of Alkanes

2

• The most important hypothesis in all of
• biologyis 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)

3
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

4
Alkanes

• Contain C and H only
• Contain single bonds C-C
• Have 4 bonds to every carbon (C) atom
• Are nonpolar

5
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 Names

• Name carbons Structural Formula
• Methane 1 CH4
• Ethane 2 CH3CH3
• Propane 3 CH3CH2CH3
• Butane 4 CH3CH2CH2CH3
• Pentane 5 CH3CH2CH2CH2CH3

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IUPAC NAMES

• Name carbons Structural Formula
• Hexane 6
  CH3CH2CH2CH2CH2CH3
• Heptane 7 CH3CH2CH2CH2CH2CH2C
  H3
• 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

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Reactions of Alkanes

• Combustion
• alkane O2 CO2 H2O heat

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Combustion In the Cell

• Metabolic oxidation is combustion
• C6H12 O6 6O2 6CO2 6H2O heat
• glucose

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Learning Check Alk2

• Complete the combustion reaction for
• C3H8 O2
• Balance your equation

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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

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Learning Check Alk3

• Complete and balance the reaction for the
  complete combustion of C7H16

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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