Alkenes

In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond.[1] The simplest acyclic alkenes,with only one double bond and no other functional groups, form an homologous series of hydrocarbons with the general formula CnH2n.[2]
The simplest alkene is ethylene (C2H4), whichhas the International Union of Pure and Applied Chemistry (IUPAC) name ethene. Alkenes are also called olefins (an archaic synonym, widely used in the petrochemical industry). Forbridged alkenes, the Bredt's rule states that a double bond cannot be placed at the bridgehead of a bridged ring system, unless the rings are large enough. Aromatic compounds areoften drawn as cyclic alkenes, but their structure and properties are different and they are not considered to be alkenes.
The main uses of the first eight saturatedhydrocarbons, including some positives and negatives aspects of their uses
Hydrocarbons

The alkenes ( asub-set of the set of hydrocarbons) are the main constituents of natural gas andcrude oil. The first eight are

Methane
-Natural gas (cooking and heating).
-Cause of Global warming
Ethane \
-Used to make polythene
- Hog and poultry producers, grainelevator operators and grain are negatively affected
Propane
-In gas cylinders for homes , fuel of buses
- As any odorless gas with potentially harmful effects is inherentlydangerous
Butane
-Camping gaz
-inhaling large amounts of butane is definitely not good for you
Octane
-A component of petrol
-Burn

Physical Properties
• Nonpolar,insoluble in water.
• Soluble in most organic solvents.
• Boiling points similar to alkane of same
size.
• Less dense than water.
• Up to 4 carbons, gas at room temperature.