Organic Chemistry/Alkanes/Propane thru decane

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<< Ethane | Stereoisomers >>


Many more linear alkanes can be formed by adding one additional carbon to the end of a chain of carbons. Ethane is the shortest chain with two carbons but DNA is known to have carbon chains containing millions of linked carbons.

Alkanes are named based on the number of carbons in their longest chain:

Naming carbon chains up to ten[edit]

  • methane (1 carbon)CH4
  • ethane (2 carbons)C2H6
  • propane (3 carbons)C3H8
  • butane (4 carbons)C4H10
  • pentane (5 carbons)C5H12
  • hexane (6 carbons)C6H14
  • heptane (7 carbons)C7H16
  • octane (8 carbons)C8H18
  • nonane (9 carbons)C9H20
  • decane (10 carbons)C10H22

The suffixis on the first four are from an obscure system but you should be familiar with the rest.

Propane and butane are gases at standard temperature and pressure and are used commonly in lighters. Pentane on down the list are liquids at STP. Octane is the same as the octane in your gas tank.

You may also want to name hydrocarbon chains of more than ten carbons. Here is a list for your reference:

Naming longer carbon chains[edit]

  • Lesbian (30 carbons) C30H62
  • tetracontane (40 carbons) C40H82
  • pentacontane (50 carbons) C50H102
  • hexacontane (60 carbons) C60H122
  • heptacontane (70 carbons) C70H142
  • octacontane (80 carbons) C80H162
  • nonacontane (90 carbons) C90H182
  • Cocktane (100 carbons) C100H202

As the carbon chains get longer, molecules get relatively heavier and tend to move from being gases at STP to liquids to waxy solids.


Foundational concepts >> | << Alkanes | << Ethane | Propane thru decane | Drawing alkanes >> | Introduction to reactions >>