Chapter 7 Carbon and Organic Compounds

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Chapter 7 Carbon and Organic Compounds
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Organic Chemistry

• Organic originally meant 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

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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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Organic Chemistry and Hydrocarbons

• Over a million organic compounds, with a dazzling
  array of properties
• Why so many? Carbons unique bonding ability!
• Lets start with the simplest of the organic
  compounds Hydrocarbons

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Hydrocarbons

• Hydrocarbons contain only two elements hydrogen
  and carbon
• simplest hydrocarbons called alkanes, which
  contain only single covalent bonds
• methane (CH4) with one carbon is the simplest
  alkane also known as swamp gas main component
  of natural gas.

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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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alkanes

• Carbon has 4 valence electrons, thus forms 4
  covalent bonds
• not only with other elements, but also forms
  bonds WITH ITSELF.
• Ethane (C2H6) is the simplest alkane with a
  carbon to carbon bond

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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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Straight-Chain Alkanes

• Straight-chain alkanes contain any number of
  carbon atoms, one after the other, in a chain -
  meaning one linked to the next
• C-C-C C-C-C-C etc.

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Straight-Chain Alkanes

• Many alkanes are used for fuels methane,
  propane, butane, octane
• As the number of carbons increases, so does the
  boiling and melting pt.
• The first 4 are gases 5-15 are liquids higher
  alkanes are solids

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Alkanes

• Since the electrons are shared equally, the
  molecule is nonpolar
• thus, not attracted to water
• oil (a hydrocarbon) not soluble in H2O
• like dissolves like

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Naming Straight-Chain Alkanes

• Names recommended by IUPAC - the International
  Union of Pure and Applied Chemistry
• end with -ane, the root part of the name is a
  prefix for the of carbons Table 7-3, page 244

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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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• Name carbons Structural Formula
• Hexane 6 CH3CH2CH2CH2CH2CH3
• Heptane 7 CH3CH2CH2CH2CH2CH2CH3
• Octane 8 CH3CH2CH2CH2CH2CH2CH2CH3
• Nonane 9 CH3CH2CH2CH2CH2CH2CH2CH2CH3
• Decane 10 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3
  

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Straight-Chain Alkanes

• Homologous series- a group of compounds that have
  a constant increment of change
• In alkanes, it is -CH2-

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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?

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Solution

• A. CH3CH2CH2CH3
• B. C4H10
• C. butane