Water

Water is the most important natural resource, more than 70% of earth's surface is occupied by water.

The formula of water is H2O.
Water is a compound

• It is made up of two hydrogen and one oxygen in fixed proportion .
• The properties of water is different from the constituent elements.
• The elements which are present in water are separated by chemical means not by physical methods.

The circulation of water from earth's surface to the atmosphere by evaporation and back to the earth's surface by precipitation is known as water cycle.