The Chemistry of Water

H20, more commonly known as water, is composed of two hydrogen atoms and one oxygen atom.H20, more commonly known as water, is composed of two hydrogen atoms for every oxygen atom. Water can exist in three phases, ice as a solid, water as a liquid and water vapor in the gaseous state.

Some of the major physical and chemical properties of water include:
Water in its natural state is a liquid.
Because hydrogen has a lower electronegativity than oxygen, water is a polar molecule. The oxygen has a slight negative charge while the hydrogens have a slight positive charge giving the article a strong dipole moment. The interactions between the different dipoles of each molecule cause a net attraction force associated with water’s high amount of surface tension.
Another very important force that causes the water molecules to stick to one another is the hydrogen bond. These bonds are very weak and are what cause soap to break down water easily.
The boiling point of water is related to the barometric pressure. For example, on the top of Mt. Everest water boils at about 154 F, compared to 212 F at sea level. Conversely, water deep in the ocean near geothermal vents can reach temperatures of hundreds of degrees and remain liquid.
Because water is polar, it has a high surface tension caused by a strong cohesion between water molecules. It also has a strong adhesion.
Capillary action refers to the tendency of water to move up a narrow tube against the force of gravity.
Water is a very strong solvent, referred to as the universal solvent, dissolving many types of substances. Substances that will mix well and dissolve in water, are known as “hydrophilic” substances, while hydrophobic substances are those that do not mix well with water.
Pure water has a low electrical conductivity, but this increases significantly upon solvation of a small amount of ionic material such as sodium chloride.
The maximum density of water is at 39.16 F. Water becomes less dense when it freezes, expanding by 9%. This causes an unusual phenomenon: ice floats upon water, meaning water organisms can live inside a partly frozen pond because the water on the bottom has a temperature of around 39 C.
Water forms an azeotrope with many other solvents.
Some substances (lithium, potassium, sodium, calcium) create a flammable gas when wet, or react violently with water.
Because water is transparent, aquatic plants can live in water because sunlight can reach them. The only thing absorbed by water are strong UV rays.