WATER AND ITS PROPERTIES

 Water is considered as a compound not an element

i) Hydrogen and Oxygen are combined in a fixed proportion by weight.
ii) Properties of water differ from the properties of hydrogen and oxygen
iii) The components can be separated by Chemical methods.

Water Cycle: It involves the process of evaporation, condensation and precipitation.
It helps in balancing the amount of water both in the atmosphere and on the earth's surface.
Importance of water cycle:
i) Regulating the climate of the earth
ii) Makes water available in various forms on the earth

Sources of Water:

1) Surface water:                     i) Ocean and Sea Water     ii) River and Lakes Water
 2) Under Ground Water:        i) Spring Water                   ii)Well Water
3) Above Surface Water:         Rain Water

Water is an universal solvent

Water is added to the atmosphere by 

i) Evaporation    ii) Burning of Fossil Fuels     iii) Respiration iv) Transpiration by Plants

Impurity Present in water

i) Lowers its freezing Point     ii) Increases its boiling point

Anomalous Expansion Of water:
https://youtu.be/adUU1AsWwVI

Potable Water: Water which is suitable for drinking is called potable water. It is colourless and odourless.The density of water is maximum at 4 degree Celsius.

Impotant Questions:

i)  Why doesn't sea water freeze easily?
ii) State the importance of water cycle in nature?
iii) Give reasons:
a) Ice floats on water
b) Water pipes burst in severe winter
c) Water is used as a cooling agent
iv) How does anomalous expansion of water help the aquatic organisms in cold climate?
v) What is the effect of boiling point of water when impurity is added?