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	Atomic world
	Chemical Reactions
	Organic Chemistry
	Air
	Water
	Introduction
	Structure and Nature of water
	Physical properties
	Chemical Properties
	Unique Properties
	Water Treatment
	Desalination
	Water Pollution

Physical Properties of water
Three times more abundant than all other substances One of few inorganic liquids Only substance that occurs naturally as a solid, liquid and gas Universal solvent Highest surface tension of all liquids except mercury Expands upon freezing (by 9%), a property shared with few other substances Expands with increasing temperature above 4⁰C Greatest heat capacity of all liquids (1 cal/g/⁰C) Greatest latent heat of fusion and vaporization Greatest thermal conductivity except for mercury High transparency Like air, a highly mobile substance A dense liquid and therefore only slightly compressible
Thermal Properties of water Melting and boiling points H₂0 changes state from solid to liquid at the melting temperature and from liquid to gas at the boiling temperature. Water melts and boils at an amazingly high temperature for a compound made up of such light elements. The reason for the high melting and boiling temperatures is the hydrogen bonding between water molecules that causes them to stick together and to resist being pulled apart which is what happens when ice melts and water boils to become a gas. Without this 'stickiness' water would not be a liquid over much of the surface of the Earth where temperatures are relatively high and we would not have an ocean.
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