ACKNOWLEDGEMENT:
Figure
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Source of Figure
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Figure 13a
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http://2012books.lardbucket.org/
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Figure 13b
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https://www.flickr.com/
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Figure 14
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https://sites.google.com/site/internationalgcsechemistry/
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Figure 15
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en.wikibooks.org
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Chemical Properties
of Alkanes:
Alkenes undergo 3 types of chemical reactions. They are:
- Combustion
- Addition
- Polymerization
Alkenes react with oxygen in the presence of heat, to form
carbon dioxide and water.
Addition Reaction:
Alkenes have a temporary double bond, which breaks to form
different types of compounds, depending on the other reactant present.
Example:
- Addition reaction of ethene with Bromine:
Ethene reacts with bromine, to form
Dibromoethane.
This reaction decolourises bromine
water and is used as a test for
unsaturation.
Figure 13:
Test for Unsaturation: (L) Before ; (R) After
If an alkane if
added to bromine water, no reaction will take place and bromine water would not
be decolourised.
- Addition reaction of ethene with steam:
Ethene reacts with steam, at 300°C
temperature and 60 atmosphere pressure, with Phosphoric acid as a catalyst, to
form ethanol.
Figure 14:
- Addition reaction of ethene with Hydrogen:
Ethene reacts with hydrogen, in the
presence of Palladium or Nickel as a catalyst to yield ethane.
Figure 15:
This process is knows as
hydrogenation of alkenes.