15.2.2

Alkanes

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Alkanes

Hydrocarbons are organic compounds made of carbon and hydrogen. Hydrocarbons are the dominant compounds in crude oil. Most of these hydrocarbons are alkanes.

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Alkane structure

  • In alkanes, carbon atoms bond to four atoms (hydrogen or carbon).
  • We call them saturated hydrocarbons as all their bonds with other atoms are single bonds.
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Alkane uses

  • Alkanes have quite low reactivity, but they combust quite well.
    • This makes them useful as fuels.
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General formula

  • Alkanes have the general formula CnH(2n+2)
    • E.g. if a hydrocarbon contained 7 carbon atoms, the number of hydrogen atoms would be (2 x 7) + 2 = 16
  • So, the formula for the hydrocarbon shown in the image would be C7H16
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Reaction with chlorine

  • Although alkanes are quite unreactive, they will react with chlorine in the presence of UV light. The UV light activates the chlorine molecule, which starts the reaction.
  • The overall reaction is a substitution reaction, as one hydrogen atom on the hydrocarbon is replaced by chlorine.
  • The products formed are a chloroalkane and hydrogen chloride.

Jump to other topics

1States of Matter

2Elements, Compounds & Mixtures

3Atomic Structure

4The Periodic Table

5Chemical Formulae, Equations & Calculations

6Bonding

7Electrolysis

8Groups of the Periodic Table

9The Atmosphere

10Reactivity Series

11Metal Extraction

12Acids & Alkalis

13Chemical Tests

14Physical Chemistry

15Organic Chemistry

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