What's in Crude Oil?

Crude oil was formed from the fossilised remains of tiny sea plants and animals as they were compressed under layers of sediments. As a result, it is a __________ of a very large number of __________.

Most of the compounds in crude oil consist of hydrocarbons. A hydrocarbons is a molecules made up of __________ and __________ atoms only.

Note: In an exam answer you must include the word 'only' in the definition to gain the mark.

There are two key types of hydrocarbons:

Much of crude oil are saturated hydrocarbons - alkanes. These are only have single bonds and so can not join with any more atoms.

Ethane

Propane

Alkanes have the general formula CnH2n+2 and you need to be able to reconise them in this way and also from their molecule diagrams.

Alkenes are like Alkanes in that they are __________ chains. The difference is, Alkenes contain a double covalent bond between two of the carbons.

Ethene

Propene

With this double bond comes a name change. The -ane ending becomes an -ene ending. For example: ethane becomes ethene. An easy way to remeber this is if there are two 'e's in the ending then there is a double bond. Alkenes have the general formula CnH2n

Hydrocarbon Alkane
or Alkene
__________
C10H20 __________
Octane __________
__________
C20H42 __________
Butene __________