The Alkenes
An overview of the alkenes, the alkenes:
- Are members of the hydrocarbon family.
- Are made of just HYDROGEN and CARBON.
- Are made up of chains of carbon atoms with single and double covalent
bonds between them. The double bonds make them far more reactive than alkanes.
- Are UNSATURATED (contains double bonds) and decolourise bromine
water.
- Are mostly used to make other chemicals and polymers, they burn with
a sooty flame to produce carbon dioxide, soot (carbon) and water.
- Have the general chemical formula CnH2n
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C2H4 The simplest alkene is ethene (notice that the
word ends in'ene'), each molecule contains two carbon joined to 4 hydrogens. |
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C3H6 The next alkene is propene, each molecule contains
three carbons joined to 6 hydrogens. Notice the double covalent bond between the
two carbon atoms. Count the bonds around each carbon atom . . . . . . they all
have 4. |
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C4H8 The next alkene is butene, each molecule contains
four carbons joined to 8 hydrogens. The carbons are starting to form a chain.
It's not important to know this for GCSE but notice that you can get different
molecules of butene depending upon where the double bond is. |
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The carbon chain can get longer (just like the alkane family).
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Go to Polymers
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