Distribution in nature
Potassium is widely distributed in nature, its content in the lithosphere is about 2.5% by weight.It is part of mica and feldspar.Potassium accumulates in magmatic processes taking place in the silicic magma, and then crystallized in granites and other rocks.
This chemical element migrates slightly on the earth's surface, the weathering of rocks is partially goes into the water, where the captured organisms and absorbed by clay.The rivers are poor in potassium, it enters into the ocean in less than sodium.In the ocean, potassium absorbed by the body, it is part of the bottom silt.
plants get potassium from the soil, it is one of the most important nutrients.The daily requirement of potassium in adults is 2-3 g Potassium is concentrated mainly in the cells in the extracellular env
ironment, it is much less.
Physical and chemical properties
Potassium - a very soft metal, it can be easily cut with a knife.He body-centered cubic crystal lattice.The chemical activity of the element is higher than that of other metals.It is due to the remoteness of the single valence electron from the nucleus of an atom of potassium.
Potassium is rapidly oxidized in air, especially in the wet, so it is stored in gasoline, mineral oil or kerosene.This metal is very strongly reacts with water, releasing hydrogen, this reaction is sometimes accompanied by explosion.It is slowly soluble in ammonia, wherein the blue solution is a strong reducing agent.
At room temperature, potassium reacts with halogens, with gentle heating - with sulfur, with a stronger - tellurium and selenium.At temperatures above 200 ° C in an atmosphere of hydrogen, it forms a hydride, which ignites spontaneously in air.Potassium does not interact with the nitrogen even under heat and pressure, but under the influence of an electrical discharge forms nitride and potassium azide.The presence of potassium is determined by flame violet color.
Preparation and use
In industry potassium obtained by exchange reactions between the metal and sodium hydroxide or potassium chloride.It is sometimes used to heat the mixture of potassium chloride with aluminum and lime to 200 ° C.
main consumer of potassium salts - agriculture, the chemical element included in the potash.Sodium potassium alloys used in nuclear reactors as a coolant and as reducing agents in the production of titanium.Prepared from metallic potassium peroxide intended for oxygen recovery in submarines.
- HiMiK.ru, Potassium