revision past year paper

Organic Chemistry - Introduction

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Basic definitions for organic chemistry
Scope

Organic chemistry is a vast subject so it is easier to split it into small sections for study.
This is usually done by studying compounds which behave in a similar way because they have a particular atom, or group of atoms, (FUNCTIONAL GROUP) in their structure.

Catenation

The ability to form bonds between atoms of the same element. Carbon catenates to form chains and rings, with single, double and/or triple covalent bonds.

Q.1

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Why does carbon form so many catenated compounds ?

• Why does silicon undergo catenation to a lesser extent than carbon ?

Homologous
Series
A series of compounds of similar structure in which each member differs from the next by a common repeating unit, CH2 . The members of the series are called homologues.
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Functional
Groups

All share the same general formula.
Formula of a homologue differs from its neighbour by CH2. (e.g. CH4, C2H6, . . . etc )
Contain the same functional group(s).
Have similar chemical properties.
Show a gradual change in physical properties as molar mass increases.
Can usually be prepared by similar methods.

• Can consist of one atom, a group of atoms or multiple bonds between carbon atoms.

• Each functional group has its own distinctive properties which means that the properties of a compound are governed by the functional group(s) in it.
H
H

H

H

H

H

C

C

C

C

C

H

H

H

H

H

carbon skeleton

Q.2

H
H

OH

H

H

H

H

C

C

C

C

C

H

H

H

H

H

carbon skeleton

functional group NH 2 functional group

The following list contains some molecular formulae. Draw out as many legitimate structures for each and classify each compound made according to the functional group present.
Remember that carbon atoms will have four covalent bonds surrounding them, oxygen atoms
will