4 Alkenes Flashcards
What are alkenes?
They are a homologous series of hydrocarbons which contain a carbon-carbon double bond.
What is the functional group of alkenes?
> C=C<
How do you draw ethene?
How do you draw propene?
How do you draw but-1-ene?
How do you draw pentene?
How do you know what number should be used in the naming of the alkene?
It is the location of the double bond in terms of the chain of carbon.
What happens if there are two double bonds?
You specify in the answer where they are on the carbon molecule by using numbers.
What happens to the amount of hydrogens when there is a double bond?
There is only one carbon instead of two.
What is the general formula for alkenes?
CnH2n.
Why are alkenes classified as unsaturated hydrocarbons?
They contain double carbon bonds. They have 2 fewer hydrogen atoms than the alkane with the same number of carbon atoms.
How do addition reactions happen with alkenes?
Part of the double bond breaks to become a single C-C bond and the electrons are used to join other atoms on to the two carbon atoms.
How does bromine add to alkenes?
They don’t have any need for heat, light or a catalyst.
What is an example of an addition reaction?
Bromine water and ethene
What is the word equation for the addition reaction between bromine water and ethene?
Ethene + Bromine –> 1,2 dibromoethane
What is the formula for the addition reaction between bromine water and ethene?
CH2=cH2 + Br2 –> CH2BrCH2Br.
How do you test for an alkene or an alkane?
You test with bromine water.
What is the method to test if its an alkane or an alkene for a liquid and gas.
If you shake an unknown organic compound with bromine water (orange solution) becomes decolourised, it is an alkane. If it is an alkene the orange solution will stay orange.
If its a gas you just bubble it through the bromine water and it should produce the same results.
What do we call the molecule if it has a chlorine in it?
Chloro-
What do we call the molecule if it has a bromine in it?
Bromo-
