Earth science for schools by Moorland School

The Alkanes

An overview of the alkanes, the alkanes:

  • Are members of the hydrocarbon family.
  • Are made of just HYDROGEN and CARBON.
  • Are made up of chains of carbon atoms with single covalent bonds between them.
  • Are SATURATED (single bonds) and don't decolourise bromine water.
  • Are mostly used as fuels, they burn cleanly to produce carbon dioxide and water. Carbon dioxide is a greenhouse gas which contributes to global warming.
  • Have the general chemical formula  CnH2n+2
methane structure.gif (1578 bytes) CH4  The simplest alkane is methane (notice that the word ends in'ane'), each molecule contains one carbon joined to 4 hydrogens.
ethane structure.gif (2845 bytes) C2H6  The next alkane is ethane, each molecule contains two carbons joined to 6 hydrogens.
propane structure.gif (2915 bytes) C3H8  The next alkane is propane, each molecule contains three carbons joined to 8 hydrogens. The carbons are starting to form a chain.
butane structure.gif (3359 bytes) C4H10   This one's called butane, it has a boiling point of -0.5°C
The carbon chain can get longer . . . C5H12 one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)   boiling pt 36°C
C6H14 one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)   boiling pt 69°C
C7H16 one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)   boiling pt 99°C
C8H18 one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)   boiling pt 126°C
C9H20 one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)   boiling pt 151°C
C10H22 one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)one carbon small.gif (664 bytes)   boiling pt 174°C

and so on . . . .

CnH2n+2

The carbon chain is sometimes called a 'backbone'. For GCSE it is important to learn the trends in physical and chemical properties as the number of carbon atoms go up or down. Don't learn all the numbers! Click here for an overview of the trends

Back to Oil and Gas
• The Rock Cycle 
• Plate Tectonics
• Earth Structure
• Earth Origin
• Volcanoes
• Earth's Atmosphere
• Fossil Fuels
• Polymers
• home

Moorland School
Clitheroe,
Lancashire
BB7 2AJ
England
email