Water is defined as a colorless, transparent, odorless liquid which forms the seas, lakes, rivers and rain and is the basis of the fluids living organisms. It is main constituent on the earth’s surface.

• Density – 1g/cm^3
• Boiling point -100 degree centigrade
• Formula – H2O
• Melting point – 0 degree centigrade
• Molar mass – 18.01528g/mol
• IUPAC IP – water, oxidane

The three forms of water.

• Solid
• Liquid
• Gas (vapour)

Water molecule contains one oxygen and two hydrogen atoms that are connected by covalent bonds. The invisible part of clouds that you cannot see is water vapour and dry air. A cloud is a mixture of gas, liquid and solids.

WATER COMPOSITION ON EARTH’S SURFACE: Water covers 71% of the total Earth’s surface. It is vital for all known forms of life. On Earth, 96.5% of the planet’s crust water is found in seas and oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, and 0.001% in the air as vapour, clouds (formed of ice and liquid water suspended in air), and precipitation. Only 2.5% of this water is freshwater and 98.8% of that water is in ice (excepting ice in clouds) and groundwater. Less than 0.3% of all freshwater is in rivers, lakes, and the atmosphere, and an even smaller amount of the Earth’s freshwater (0.003%) is contained within biological bodies and manufactured products. A greater quantity of water is found in the earth’s interior.