12'5 Cycloalkanes

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Chapter 12 Alkanes

• 12.5 Cycloalkanes

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Cycloalkanes

• Cycloalkanes
• Are rings of carbons that can be drawn as
  geometric figures.
• Have a general formula of CnH2n or 2 H less than
  the alkane.
• propane C3H8 cyclopropane C3H6.
• butane C4H10 cyclobutane C4H8.
• Are named with the prefix cyclo- in front of the
  corresponding alkane name.

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Formulas of Cycloalkanes

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Naming Cycloalkanes

• A cycloalkane with
• One substitutuent is named by placing the name of
  the substituent in front of the cycloalkane name.
• Two or more substitutuents is named by numbering
  the ring in the direction that gives the lower
  numbers to the substituents.

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Cycloalkanes with Side Groups
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Constitutional Isomers

• The rigid ring in a cyclic structure prevents
  rotation of substitutuents bonded to the ring.
• A cyclic structure with two substituents has two
  isomers called cis-trans isomers.
• The cis isomer, has two substituents on the same
  side of the ring.
• The trans isomer, has two substituents on
  opposite sides of the ring.

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Cis-Trans Isomers

• The compound 1,2-dichlorocyclopropane has
  cis-trans isomers.
• Cl atoms on Cl atoms on
• same side opposite sides