Organic Chemistry 1
Compounds that contain carbon are called organic compounds.
Organic chemistry is a branch of chemistry that deals with Hydrocarbons. Hydro carbons are compounds the contain Carbon and Hydrogen only.
There are three types of Hydrocarbons. They are
- Alkanes
- Alkenes
- Alkynes (not part of syllabus)
Alkanes
The molecules within this family contain carbon atoms all covalent bonded to four other atoms by single bonds.
They are saturated hydrocarbons because they only have single bonds and no further atoms can be added.
All its compounds have a similar structure and similar name endings. They also behave chemically in the same way. having these factors in common is called a homologous series
All the members of this family have the formula : CnH2n+2(n is the no of carbon atoms present)
Each member in the series differs by CH2
The members of the series are
H
|
METHane – CH4 – H——C——H
|
H
ETHane – C2H6
PROPane – C3H8
BUTane – C4H10
PENTane – C5H12
HEXane – C6H14
Structural isomerism
Any Hydrocarbons containing 4 or more carbon atoms in their molecular formula can be written with a different structural formula. These compounds are called isomers of the original compound.
Eg :- Butane – C4H10
Can be written as
H H H H
| | | |
H——C——C——C——C—-H ———— BUTENE
| | | |
H H H H
Or as
H H H
| | |
H——C——C——C——H —————— 2- METHYL PROPANE.
| | |
H | H
|
|
H————C————H
|
H
The Chemical Behaviour of Alkanes
Alkanes are rather unreactive because they are saturated hydrocarbons. They are generally not affected by alkalis, acids and other substances. However, their most imp property is that they burn easily.
Gaseous alkanes burn easily in a good supply of air, forming carbon dioxide and water as well as plenty of heat energy
Methane,or natural gas, for example is used in cooking as well as for heating offices, schools and homes.
prepIGCSE 