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Alkenes
Before reading through this section it might be a good idea to cover the content of alkanes.
Also check out our video section on Alkanes and Alkenes
Alkenes are unsaturated so they contain double covalent bond between two carbon atoms.
Ethene
Each carbon atom now shares 2 electrons with another carbon, meaning carbon only has 2 extra electrons to share with 2 other hydrogen atoms.
Also check out our video section on Alkanes and Alkenes
Alkenes are unsaturated so they contain double covalent bond between two carbon atoms.
Ethene
Each carbon atom now shares 2 electrons with another carbon, meaning carbon only has 2 extra electrons to share with 2 other hydrogen atoms.
You're almost always likely to come across alkene molecules with just one double bond, although there can be more.
Propene
The next alkene in the series is known as propene, as with the alkanes we can represent the covalent bonds with just lines. This is known as a displayed formula.
Propene
The next alkene in the series is known as propene, as with the alkanes we can represent the covalent bonds with just lines. This is known as a displayed formula.
An alkene means there is a double bond between a pair of carbon atoms, between the other pair there is just a single bond. Each carbon has to have in total of four bonds. The middle carbon has only one bond because it has already three bonds with the other two carbon atoms.
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Butene
Here is the displayed formula of Butene, notice how each carbon has four bonds, one pair of carbons has to have a double bond, this defines an alkene.
General formula
Just like the alkanes we can use a general formula to work out how many hydrogen atoms there will be on an alkene molecule.
CnH2n
Just like the alkanes we can use a general formula to work out how many hydrogen atoms there will be on an alkene molecule.
CnH2n
Decene
So using the general formula we can work out how many hydrogen atoms there will be on decene (10 carbon atoms)
n=10
2n
2x10 = 20
So Decane has 20 hydrogen atoms
So using the general formula we can work out how many hydrogen atoms there will be on decene (10 carbon atoms)
n=10
2n
2x10 = 20
So Decane has 20 hydrogen atoms
Now you should have a better understanding on alkanes and alkenes, attempt the questions below:
| hydrocarbon_questions.doc |
