12.2 - Alkenes
What are alkenes?
Ethenes have double bonds, so they are unsaturated hydrocarbons. Non-cyclic alkenes have the general formular of CnH2n They are named by:
- The number of carbons eg. Propene has 3 carbons
- Where the double bond is attached eg. But-1-ene means the double bond is on the first carbon.
Skeletal Formula is used commonly to show the structure of alkenes. Eg. But-1-ene.
The boiling points of alkenes increase as the number of carbons increase.
There are cycloalkenes and dienes (with 2 double bonds).
Shapes of alkenes
The C=C bonds in all alkenes are arranged in the same way. C=C bonds are in a planar arrangement, as the electrons around the carbons repel eachother to an angle…