Views:3 Author:Site Editor Publish Time: 2019-11-04 Origin:Site
Small encyclopedia of chemical material – Water
It is vital for all known forms of life, even though it provides no calories or organic The chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Water is the name of the liquid state of H2O at standard ambient temperature and pressure. It forms precipitation in the form The fine state of water is in the form of fog. Clouds are formed from the water droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.
Water covers 71% of the Earth's surface, mostly in seas and oceans.Small portions of water occur as groundwater (1.7%), in the glaciers and the ice caps of Antarctica and Greenland (1.7%), and in the air As vapor, clouds (formed of ice and liquid water suspended in air), and precipitation (0.001%).
Water plays an important role in the world economy. Approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a major source of food for many parts of the world. Much of long- Distance trade of commodities (such as oil and natural gas) and manufactured products is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a wide variety of substances both mineral and organic; as such it is widely used in industrial processes, and in cooking and washing. Water, ice and snow are also central to many sports and other forms of entertainment, such As swimming, pleasure boating, boat racing, surfing, sport fishing, diving, ice skating and skiing.
Water (H2O) is a polar inorganic compound that is at room temperature a tasteless and odorless liquid, nearly colorless with a hint of blue. This simplest hydrogen chalcogenide is by far the most studied chemical compound and is described as the "universal solvent" for its ability to dissolve many substances. This allows it to be the "solvent of life".It is the only common substance to exist as a solid, liquid, and gas in normal terrestrial conditions.
Type of water
Different disciplines have different names for water:
Depending on the water quality, it can be divided into:
Soft water: Contains sodium ions, potassium ions (alkali metals), and water with a hardness of less than 8 degrees is soft water.
Hard water: contains magnesium ions, calcium ions (alkaline earth metals), and water with a hardness higher than 8 degrees is hard water. Hard water can affect the effect of the detergent, and hard water will have a small amount of scale.
According to the content of sodium chloride, it can be divided into:
Generally there are:
Biological water: water in different states that exist in various life systems
Natural water: Natural water constitutes a general term for various forms of water on the surface of the earth. It includes rivers, oceans, glaciers, lakes, swamps and other surface waters, as well as natural water bodies such as groundwater in the rock layers.
Soil water: water stored in the soil
Groundwater: water stored underground
Ultrapure water: extremely high purity water, mostly used in the integrated circuit industry
Pure water: high purity water, considered to be non-conductive
Crystal water: Also known as water. In a crystalline material, a quantity of water molecules bound by a chemical bond to an ion or molecule.
The chemical formula of heavy water is D2O, and each heavy water molecule is composed of two monomer atoms and one oxygen atom. Heavy water accounts for less than two-tenths of a percent of natural water, and heavy water obtained by electrolyzing water is more expensive than gold. A moderator and a heat carrier for the atomic reactor.
Extra heavy water is extremely rare in natural water, and its proportion is less than one part per billion. The production cost of excess water is 10,000 times higher than that of water.
The semi-heavy water has a chemical formula of HDO, and each molecule contains one hydrogen atom, one atom and one oxygen atom.
Water is widely used in chemical reactions as a solvent or reactant and less commonly as a solute or catalyst. In inorganic reactions, water is a common solvent, dissolving many ionic compounds, as well as other polar compounds such as ammonia and compounds closely related to water. In organic reactions, it is not usually used as a reaction solvent, because it does not dissolve the reactants well and is amphoteric (acidic and basic) and nucleophilic. Nevertheless, these properties are sometimes desirable. Also, acceleration of Diels-Alder reactions by water has been observed. Supercritical water has recently been a topic of research. Oxygen-saturated supercritical water combusts organic pollutants efficiently. Water vapor is used for some processes in the chemical industry. An example is the production of acrylic acid from acrolein, propylene and propane. The possible effect of water in these reactions includes the physical-, chemical interaction of water with the catalyst and the chemical reaction of water with the reaction intermediates.