Chemical Nature of Carbon

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Chemical Nature of Carbon

• Valence electrons?
• Ionic bonding?
• Number of bonds?

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Uses of Hydrocarbons
Number of C atoms State Major Uses
1-4 gas heating and cooking fuel
5-7 liquids, (low boiling) solvents, gasoline
6-18 liquids gasoline
12-24 liquids jet fuel camp stove fuel
18-50 liquids, (high boiling) diesel fuel, lubricants, heating oil
50 solids petroleum jelly, paraffin wax
1-4 gas heating and cooking fuel
5-7 liquids, (low boiling) solvents, gasoline
6-18 liquids gasoline
12-24 liquids jet fuel camp stove fuel
18-50 liquids, (high boiling) diesel fuel, lubricants, heating oil
50 solids petroleum jelly, paraffin wax
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Saturated Hydrocarbons

• a saturated hydrocarbon has all C-C single bonds
• it is saturated with hydrogens
• saturated aliphatic hydrocarbons are called
  alkanes
• chain alkanes have the general formula CnH2n2

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Formulas

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Formulas
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Isomerism

• Isomers different molecules with the same
  molecular formula
• Structural Isomers different pattern of atom
  attachment

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Rotation about a bond is not isomerism
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Possible Structural Isomers
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3.4 Naming Alkanes

• Compounds are given systematic names by a process
  that uses
• Follows specific rules
• Find parent hydrocarbon chain
• Carbons in that main chain are numbered in
  sequence
• Substituents are identified numbered
• Write compound name is single word
• Name a complex substituents as though it were a
  compound itself

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Naming Alkanes

• Find the longest continuous carbon chain
• Number the chain from end closest to a branch
• if first branches equal distance use next in
• Name branches as alkyl groups
• locate each branch by preceding its name with the
  carbon number on the chain
• List branches alphabetically
• do not count n-, sec-, t-, count iso
• Use prefix if more than one of same group present
• di, tri, tetra, penta, hexa
• do not count in alphabetizing

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Alkyl Groups
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More Alkyl Groups
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Drawing Structural Formulas
4-ethyl-2-methylhexane

• draw and number the base chain carbon skeleton
• add the carbon skeletons of each substituent on
  the appropriate main chain C
• add in required Hs

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Reactions of Hydrocarbons

• all hydrocarbons undergo combustion
• combustion is always exothermic
• about 90 of U.S. energy generated by combustion
• 2 CH3CH2CH2CH3(g) 13 O2(g) ? 8 CO2(g) 10
  H2O(g)
• CH3CHCHCH3(g) 6 O2(g) ? 4 CO2(g) 4 H2O(g)
• 2 CH3C?CCH3(g) 11 O2(g) ? 8 CO2(g) 6 H2O(g)