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Atomic symbol: H |
Atomic number: 1 |
Atomic weight: 1.0079 |
Atomic volume: 14.4 cm3/mol |
Density: 0.0000899 g/cm3 |
Period Number: 1 |
Group number: 1 |
Group name: Non-Metal |
Element classification: Non-metal |
Phase at room temperature: Gas |
Melting Point: 14.06 K |
Boiling point: 20.4 K |
Heat of fusion: 0.05868 kJ/mol |
Heat of vaporization: 0.44936 kJ/mol |
Ionization Energy: 13.598 eV |
1st ionization energy: 1312 kJ/mole |
2nd ionization energy: kJ/mole |
3rd ionization energy: kJ/mole |
Electronegativity: 2.2 |
Electron affinity: 72.7711 kJ/mole |
Specific heat: 14.304 J/gK |
Heat atomization: 218 kJ/mole atoms |
Shells: 1 |
Electron Shell Configuration: 1s1 |
Minimum oxidation number: -1 |
Maximum oxidation number: 1 |
Minimum common oxidation number: -1 |
Maximum common oxidation no: 1 |
Appearance & Characteristics |
Structure:: hcp: hexagonal close pkd |
Color: colorless |
Hardness: mohs |
Toxicity: ? |
Characteristics: diatomic,dens |
Uses: rocket fuel |
Reaction with air: vigorous, =>H2O |
Reaction with 6M HCl: none |
Reaction with 15M HNO3: none |
Reaction with 6M NaOH: none |
Number of isotopes: 3 |
Oxide(s): H2O |
Hydride(s): H2 |
Chloride(s): HCl |
Atomic Radius: 37.1 pm |
Ionic radius (1- ion): pm |
Ionic radius (1+ ion): pm |
Ionic radius (2- ion): pm |
Ionic radius (2+ ion): pm |
Ionic radius (3+ ion): pm |
Thermal conductivity: 0.18 J/m-sec-deg |
Electrical conductivity: 1/mohm-cm |
Polarizability: 0.7 A^3 |
Source: Water, methane |
Relative abundance solar system: 10.446 log |
Abundance earth's crust: 3.1 log |
Estimated crustal abundance: 1.40×103 milligrams per kilogram |
Estimated oceanic abundance: 1.08×105 milligrams per liter |
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(Gr. hydro: water, and genes: forming) Hydrogen was prepared many years before it was recognized as a distinct substance by Cavendish in 1776.
Named by Lavoisier, hydrogen is the most abundant of all elements in the universe. The heavier elements were originally made from hydrogen atoms or from other elements that were originally made from hydrogen atoms.
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Hydrogen is estimated to make up more than 90% of all the atoms -- three quarters of the mass of the universe! This element is found in the stars, and plays an important part in powering the universe through both the proton-proton reaction and carbon-nitrogen cycle. Stellar hydrogen fusion processes release massive amounts of energy by combining hydrogens to form Helium.
Production of hydrogen in the U.S. alone amounts to about 3 billion cubic feet per year. Hydrogen is prepared by
- steam on heated carbon,
- decomposition of certain hydrocarbons with heat,
- reaction of sodium or potassium hydroxide on aluminum
- electrolysis of water, or
- displacement from acids by certain metals.
Liquid hydrogen is important in cryogenics and in the study of superconductivity, as its melting point is only 20 degrees above absolute zero.
Tritium is readily produced in nuclear reactors and is used in the production of the hydrogen bomb.
Hydrogen is the primary component of Jupiter and the other gas giant planets. At some depth in the planet's interior the pressure is so great that solid molecular hydrogen is converted to solid metallic hydrogen.
In 1973, a group of Russian experimenters may have produced metallic hydrogen at a pressure of 2.8 Mbar. At the transition the density changed from 1.08 to 1.3 g/cm3. Earlier, in 1972, at Livermore, California, a group also reported on a similar experiment in which they observed a pressure-volume point centered at 2 Mbar. Predictions say that metallic hydrogen may be metastable; others have predicted it would be a superconductor at room temperature.
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Although pure hydrogen is a gas, we find very little of it in our atmosphere. Hydrogen gas is so light that, uncombined, hydrogen will gain enough velocity from collisions with other gases that they will quickly be ejected from the atmosphere. On earth, hydrogen occurs chiefly in combination with oxygen in water, but it is also present in organic matter such as living plants, petroleum, coal, etc. It is present as the free element in the atmosphere, but only less than 1 ppm by volume. The lightest of all gases, hydrogen combines with other elements -- sometimes explosively -- to form compounds. |
Great quantities of hydrogen are required commercially for nitrogen fixation using the Haber ammonia process, and for the hydrogenation of fats and oils. It is also used in large quantities in methanol production, in hydrodealkylation, hydrocracking, and hydrodesulfurization. Other uses include rocket fuel, welding, producing hydrochloric acid, reducing metallic ores, and filling balloons.
The lifting power of 1 cubic foot of hydrogen gas is about 0.07 lb at 0C, 760 mm pressure.
The Hydrogen Fuel cell is a developing technology that will allow great amounts of electrical power to be obtained using a source of hydrogen gas.
Consideration is being given to an entire economy based on solar- and nuclear-generated hydrogen. Public acceptance, high capital investment, and the high cost of hydrogen with respect to today's fuels are but a few of the problems facing such an economy. Located in remote regions, power plants would electrolyze seawater; the hydrogen produced would travel to distant cities by pipelines. Pollution-free hydrogen could replace natural gas, gasoline, etc., and could serve as a reducing agent in metallurgy, chemical processing, refining, etc. It could also be used to convert trash into methane and ethylene.
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Quite apart from isotopes, it has been shown that under ordinary conditions hydrogen gas is a mixture of two kinds of molecules, known as ortho- and para-hydrogen, which differ from one another by the spins of their electrons and nuclei.
Normal hydrogen at room temperature contains 25% of the para form and 75% of the ortho form. The ortho form cannot be prepared in the pure state. Since the two forms differ in energy, the physical properties also differ. The melting and boiling points of parahydrogen are about 0.10C lower than those of normal hydrogen.
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The ordinary isotope of hydrogen, H, is known as Protium, the other two isotopes are Deuterium (a proton and a neutron) and Tritium (a protron and two neutrons). Hydrogen is the only element whose isotopes have been given different names. Deuterium and Tritium are both used as fuel in nuclear fusion reactors. One atom of Deuterium is found in about 6000 ordinary hydrogen atoms.
Deuterium is used as a moderator to slow down neutrons. Tritium atoms are also present but in much smaller proportions. Tritium is readily produced in nuclear reactors and is used in the production of the hydrogen (fusion) bomb. It is also used as a radioactive agent in making luminous paints, and as a tracer.
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Our company is a private firm founded in 1990 with aim to develop export and import with Russia. We do promote EU industrial and consumer goods in Russia and strongly support marketing of Russian and CIS industrial products and services.
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