What are Compounds?
It is a substance which is made up of 2 or more elements
They are chemically combined together in a fixed proportion.
Carbon Dioxide (CO 2 )
One compound of CO 2 is made up of 1 Atom of Carbon and 2 atoms of Oxygen
Water (H 2 O)
One atom of H 2 O is made up of 2 Atoms of Hydrogen and 1 atom of Oxygen
A compound contains at least 2 type of Elements
Oxygen (O 2 ) is not a compound
as it contains only one type of element (O)
Water (H 2 O) is a compound
as it contains 2 elements of Hydrogen and 1 of Oxygen
Sulphuric Acid (H 2 SO 4 ) is a compound
as it contains 3 type of element Hydrogen (H),Sulphur (S) and Oxygen (O)
Properties of Compound are Different from its Elements
Property of Water (H 2 O) is different from the properties of Hydrogen and Oxygen.
Different Elements of a compound cannot be Separated by Physical Methods
We cannot use physical methods like filtration, evaporation, sublimation etc. to separate Hydrogen and Oxygen from Water.
We have to use chemical or electrochemical reactions to do the same
Elements React to Form compounds
There is a reaction between 2 or more elements to form a compound
Just mixing of 2 or more elements do not create compound
Example - Water is not just created by mixing Hydrogen and Water
A proper reaction needs to take place between 2 atoms of Hydrogen and 1 Atom of Oxygen to create water