Getting consideration of chemical and physical properties of hydrogen, it is necessary to note that in the usual state, this is a chemical element in gaseous form.A colorless gas, hydrogen is odorless, it is tasteless.For the first time the chemical element hydrogen was named after the scientist Antoine Lavoisier experiments were carried out with water, as a result of which, the world science has learned that water - a multi-component fluid, which includes hydrogen.This event happened in 1787, but long before that date, hydrogen has been known to scientists as "flammable gas".
Hydrogen in nature
According to scientists, the hydrogen contained in the earth's crust and in the water (approximately 11.2% of the total volume of water).This gas is found in many minerals that humanity over the centuries derives from the earth.Part of the properties of hydrogen are typical for oil, natural gas and clay, animal and plant organisms.But in its pure form, that is, not connected to other chemical elements of the periodic table, the gas is very rare in nature.This gas can escape to the surface during volcanic eruptions.Free hydrogen is present in minute quantities in the atmosphere.
chemical properties of hydrogen
Since the chemical properties of hydrogen neodnoobrazny, this chemical element applies to the periodic system group I and VII to the system group.As a representative of the first group, it is a hydrogen, in fact, an alkali metal, which has a degree of oxidation greater part in one of the compounds in which it is included.The same characteristic valence of sodium and other alkali metals.Because of the chemical properties of hydrogen is considered as an element, similar to these metals.
If we are talking about a metal hydride, the hydrogen ion has a negative valence of - its oxidation number is -1.Na + H- built along the same lines as the chloride Na + Cl-.This fact is the reason to include hydrogen VII to the periodic system group.Hydrogen molecules being able, under the condition that it is in a normal environment, is inactive, and can be connected exclusively with non-metals, for it more active.These metals include fluorine, in the presence of light, hydrogen combines with chlorine.If hydrogen is heated, it becomes more active, it reacts with many elements of the periodic table.
Atomic hydrogen exhibits greater chemical properties than molecular.The oxygen molecules to form water - H2 + 1 / 2O2 = H2O.By reacting hydrogen with halogens, hydrogen halides are produced H2 + Cl2 = 2HCl, and hydrogen in the reaction in the absence of light enters and sufficiently large negative temperatures - up to - 252 ° C.Hydrogen Chemical properties make it suitable for many metals recovery as reacting hydrogen absorbing oxygen from metal oxides, for example, CuO + H2 = Cu + H2O.Hydrogen is involved in the formation of ammonia nitrogen in interacting with the reaction ZN2 + N2 = 2NN3, but with the proviso that the catalyst is used, and the temperature and pressure - increased.
Vigorous reaction occurs when hydrogen reacts with sulfur in the reaction H2 + S = H2S, which result becomes hydrogen sulfide.Slightly less active hydrogen reacting with tellurium and selenium.If no catalyst is then reacted with pure carbon, hydrogen, provided only that the high temperatures are created.2H2 + C (amorphous) = CH4 (methane).In the process of hydrogen with some activity and other alkali metal hydrides are obtained, for example, H2 + 2Li = 2LiH.
physical properties of hydrogen
Hydrogen is very light chemical.At least, the scientists say, that at the moment, there is no better material than hydrogen.Its mass is 14.4 times easier for the air density of 0.0899 g / l at 0 ° C.At temperatures in the -259,1 ° C, hydrogen is able to melt - this is a very critical temperature, which is not typical for the conversion of the majority of chemical compounds from one state to another.Only an element such as helium, hydrogen exceeds the physical properties in this regard.Liquefaction of hydrogen is difficult, since it is equal to the critical temperature (-240 ° C).Hydrogen - the most teploprodny gas from all known to mankind.All the above features are the most important physical properties of hydrogen, which is used by man for a specific purpose.Also, these properties are the most relevant to modern science.