COMPOUND

 

CLASS 9th ( CHEMISTRY)

COMPOUND

Definition:

A substance that contains atoms of two or more chemical elements held together by chemical bonds is called compound.

Or

A substance consisting of atoms or ions of two or more different elements in definite proportions joined by chemical bonds into a molecule.

Properties of a compound:

Following are the main properties of a compound:

Physical properties:

A compound having different physical properties from those of its parental elements from which compounds are formed.

Example:

Water, is a compound having two Hydrogen atoms and one Oxygen atom per molecule.

Chemical properties:

A compound having different chemical properties from those of its parental elements from which compounds are formed.

Example:

Water, is a compound having Hydrogen gas which is inflammable and oxygen gas which helps in burning while water extinguish the process of burning.

Decomposition of compounds:

Compounds can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means).

Composition:

Compounds always contains the same ratio of its component atoms.

Formula of compound:

Definition:

The symbols of the elements of which compound is made and show their combining ratio to each other is called formula of a compound.

Explanation:

A compound is represented by a specific chemical formula i.e molecular formula  or structural formula( which is the combination of symbols of elements).

Examples:

Name	Formula
Benzene	C6H6
Glucose	C6H12O6
Water	H2O
Salt	NaCl
Carbondioxide	CO2