Physicochemical Characteristics of Water:

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Physical Properties of Water

1) Physical state: solid, liquid and gaseous

2) Color: colorless, however, the color of the water is due to colored substances existing in suspension or dissolved in it: organic matter from the decomposition of plants, as well as various organic products and metabolites that are usually found in them (yellowish colorations).

3) The water is tasteless and odorless. Its variation responds to two origins: natural and artificial. The former includes gases, salts, inorganic compounds, organic compounds, and compounds derived from the vital activity of aquatic organisms.

4) Density: 1 g./c.c. at 4 ° C

5) Freezing point: 0 ° C

6) Boiling point: 100 ° C

7) Critical pressure: 217.5 atm.

8) Critical temperature: 374 ° C

Chemical Properties of Water

1) Its chemical formula is H₂O: an oxygen atom linked to two hydrogen.

2) The water molecule has a positive electrical charge on one side and a negative one on the other, a property that causes its molecules to bond with each other.

3) Pure water has a neutral pH of 7: this means that it is neither acidic nor basic.

4) Reacts with acidic oxides, basic oxides and metal.

5) When water and salts unite, hydrates are formed.

Nitrogen: N can be fixed by certain microorganisms (terrestrial and aquatic), and from organic or vegetable matter, human waste (urea and ammonium) or from the dissolution of rocks (nitrates). Through microbial action, these compounds in the water are oxidized to nitrites and nitrates.

Phosphorus: Phosphorus in water comes from: (a) dissolving rocks and minerals; (b) washing of soils where it is found as other livestock or agricultural activities; (c) domestic wastewater (household detergents - tripolyphosphates - contribute 50% of the phosphorus present in urban waste). In turn, the phosphorus in a water is divided between inorganic and organic compounds (dissolved or in suspension) and phosphorus in living tissues. Likewise, phosphorus is a limiting factor for phytoplankton, but it is depleted if it is not renewed because it is not fixed from the atmosphere.

Sediments: They are the loose particles present in the soil that are transported along the slope and finally, are deposited in the channels of rivers, flat areas, reservoirs or the ocean. Rivers function as a sediment conveyor belt, carrying sediment from upstream the basin to the sea, in suspension or dragged to the bottom of the bed, depending on the size of the particles and the shear stress that the current can exert on the bed.

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