Organic Chemistry

Organic chemistry is the branch of chemistry of chemicals and compounds mainly found in living things. Perfumes, foods, drugs, detergents are some of the organic compounds found in our day to day life. Carbon is the element found mainly in organic compounds. Carbon is an element which can form four bonds with carbon or with other elements and the compounds with higher stability.  In addition Elements such as Hydrogen, Oxygen, Nitrogen, sulfur are also found in organic compounds.

Hydrocarbons

Organic compounds containing only carbon and hydrogen as the elements are called hydrocarbons. hydrocarbons are  extracted mainly from crude oil by the process of fractional distillation. Petrol diesel are few of such hydrocarbons.

alkanes

Alkanes are the simplest form of hydrocarbons. Alkanes contains only carbon and hydrogen as the elements and between the carbon atoms only single bonds are found. Alkanes are therefore high in stability and less reactive. When the alkanes are listed by the number of carbon atoms they contain we can come up with alkane homologous series.

a homologus series generally have similar reactivities and patterns of reactivity.

When naming alkanes the names are ended in 'ane'

The prefixes are found according to the number of carbon atoms. The correct prefix according to the greek number system.

1- meth
2- eth
3- prop
4-but
5-pent
6-hex
7-hept
8-oct
9- nona
......

the alkane with one carbon atom is therefore named as : Methane
 2 carbon atoms : ethane so on....

Along the homologous series physical properties  such as melting and boiling points, viscosity, flammability gradually increases as a result of increase in the size and massof the molecules

General formula is the simple formula that can be used to derive the formula of a hydrocarbon.

General formula for alkanes is Cn H2n+2 

e.g If number of Carbon atoms is 2

=C2 H2*2+2
= C2H6



As the alkanes contains only single bonds between the carbon atoms structure of the alkane can be drawn with a structural formula. In drawing the structural formula one bond between the atoms is represented using a single dash, if it was a double bond two dashes so on.

tips to draw the correct structural formula for an alkane
1. Draw the number of carbon atoms in a line with some space
2.Connect the coarbon atoms with dashes
3. fill the rest of the bonds of carbon bonded with hydrogen

Reactions of alkanes

Alkanes are usually nonreactive. However  they undergo some reactions when provided the necessary conditions.

1. burning with  oxygen

When oxygen is present in excess and when heat is provided hydrocarbons burns with oxygen to produce carbon dioxide and water. If enough oxygen is not present an incomplete combustion will occur producing the poisonous carbon monoxide in addition.

e.g: CH4+ O2 --> CO2 + H2O



2. substitution reaction with halogens

When UV light is present , alkanes undergo a free radical reaction resulting in halogenation. During haloganation, Hydrogen atoms in the alkane is replaced by halogen atoms.

e.g CH4 + Cl2 -UV-> CH3Cl

this substitution reaction can undergo as a chain reaction until CCl4 is produced

Arunigd 3:56 AM   alkane   chlorination   combustion   homologous series   hydrocarbons   naming   of   organic chemistry   physical charactors   reactions   single bonds   structure of methane

Author : Arunigd

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