4(d) Alkenes Flashcards
functional group of alkenes?
they have a double carbon fond which allows alkenes to react in ways alkanes cannot
compounds with double bonds are also…
unsaturated compounds
what does it mean if something is an unsaturated compound?
they can make more bonds with other atoms by opening up the C=C bond and allowing incoming atoms to from another single bond with each carbon atom of the functional group
- each of these carbon atoms now forms 4 single bonds instead of 1 double and 2 single bonds
what makes alkenes more reactive than alkanes?
the fact that they are unsaturated
general formula of alkenes?
CnH2n
why are alkenes more desirable?
more reactive due to the presence of the carbon-carbon double bond, so they can take part in reactions in which alkanes cannot, making them more useful than alkanes
what are alkenes used for?
used to make polymers and are the starting materials for the production of many other chemicals
examples of 2 useful reactions with alkenes?
- bromination of alkenes
- polymerisation
bromination?
- alkenes undergo addition reactions in which atoms of a simple molecule add across the C=C double bond.
- this reaction is an example of an addition reaction
what does the addition reaction of alkenes and bromine produce?
dibromoalkanes
- switch alkanes with type of alkene reacting with bromine, but add ane instead of ene
how to test for alkenes?
using the bromine water test
what is the bromine water test?
- alkenes and alkanes have different molecular structures
- all alkanes are saturated and alkenes are unsaturated
- the presence of C=C bonds allow alkenes to react in wats that alkanes cannot
- this allows us to tell alkenes apart from alkanes using a simple chemicals test called the bromine water test
how does bromine water help detect alkenes from alkanes?
bromine water is an orange coloured solution which becomes decolorized when alkenes are present which is because the bromine atoms add across the c=c bond
