NationMaster - Encyclopedia: Biohydrogen

Hydrogen (Latin: 'hydrogenium', from Ancient Greek: hydro: "water" and genes: "forming") is a chemical element in the periodic table that has the symbol H and atomic number 1. At standard temperature and pressure it is a colorless, odorless, nonmetallic, univalent, tasteless, highly flammable diatomic gas (H₂). With an atomic mass of just 1.00794 g/mol, hydrogen is the lightest element of the universe. It is also the most abundant, constituting roughly 75% of all the universe's elemental matter.^[1] It is present in water, nearly all organic compounds and in all living organisms. Hydrogen is able to react chemically with most other elements. Stars in their main sequence are overwhelmingly composed of hydrogen in its plasma state. The element is currently used primarily in fossil fuel upgrading. Other uses include as a lifting gas, as an alternative fuel (see Hydrogen economy), and more recently as a power source in fuel cells. General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... General Name, Symbol, Number lithium, Li, 3 Chemical series alkali metals Group, Period, Block 1, 2, s Appearance silvery white/gray Atomic mass 6. ... Image File history File links Download high resolution version (900x270, 18 KB) Image by Daniel Mayer and released under terms of the GNU FDL File links The following pages link to this file: Hydrogen User:Femto/elements e1 User:Eddideigel/Fantasticum ... For information about the period table of elements, see Periodic table. ... This is a list of chemical elements, sorted by name and color coded according to type of element. ... Categories: Chemical elements ... sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex... Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionisation and bonding properties. ... A periodic table group is a vertical column in the periodic table of the chemical elements. ... In the periodic table of the elements, a period is a row of the table. ... A block of the periodic table of elements is a set of adjacent groups. ... The alkali metals are a chemical series. ... A period 1 element is one of the chemical elements in the first row (or period) of the periodic table of the elements. ... The s-block of the periodic table of elements consists of the first two groups: the alkali metals and alkaline earth metals, plus hydrogen. ... Color is an important part of the visual arts. ... Hydrogen sample (gas, doesnt look like much). ... The atomic mass of a chemical element is the mass of an atom at rest, most often expressed in unified atomic mass units. ... To help compare different orders of magnitude we list here masses between 0. ... Hydrogen = 1 List of Elements in Atomic Number Order. ... Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule or other body. ... Properties The electron is a lightweight fundamental subatomic particle that carries a negative electric charge. ... A quantum mechanical system can only be in certain states, so that only certain energy levels are possible. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... A gas is one of the four main phases of matter (after solid and liquid, and followed by plasma), that subsequently appear as a solid material is subjected to increasingly higher temperatures. ... Density (symbol: Ï - Greek: rho) is a measure of mass per unit of volume. ... The melting point of a solid is the temperature at which it changes state from solid to liquid. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... A degree Celsius (Â°C) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701-1744), who first proposed a similar system in 1742. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686â€“1736), who proposed it in 1724. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... A degree Celsius (Â°C) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701-1744), who first proposed a similar system in 1742. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686â€“1736), who proposed it in 1724. ... In physics, the triple point of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium. ... In physical chemistry, thermodynamics, chemistry and condensed matter physics, a critical point, also called a critical state, specifies the conditions (temperature, pressure) at which the liquid state of the matter ceases to exist. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... The standard enthalpy change of fusion, also known as the heat of fusion, is the amount of thermal energy which must be absorbed or lost for 1 gram of a substance to change states from a solid to a liquid or vice versa. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... The standard enthalpy change of vaporization is a physical property of substances. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... Rose des Sables (Sand Rose), formed of gypsum crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... In chemical nomenclature, the oxidation number (formerly known as the Stock number) of an element in a molecule or complex is the charge that it would bear if all the ligands were removed along with the electron pairs that were shared with the central atom. ... In chemistry, an amphoteric substance is one that can react with either an acid or base (more generally, the word describes something made of, or acting like, two components). ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... Electronegativity is a measure of the attraction that an atom has for the bonding pair of electrons in a covalent bond. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... The atomic radius is the distance from the atomic nucleus to the outmost stable electron orbital in an atom that is at equilibrium. ... To help compare different orders of magnitude this page lists lengths between 10 pm and 100 pm (10-11 m and 10-12 m). ... Picometre (American spelling: picometer) is an SI measure of length that is equal to 10−12 of a metre. ... To help compare different orders of magnitude this page lists lengths between 10 pm and 100 pm (10-11 m and 10-12 m). ... In the Bohr model of the structure of an atom, put forward by Niels Bohr in 1913, electrons orbit a central nucleus. ... Covalent radius in chemistry corresponds to half of the distance between two identical atomic nuclei, bound by a covalent bond. ... To help compare different orders of magnitude this page lists lengths between 10 pm and 100 pm (10-11 m and 10-12 m). ... The van der Waals radius of an atom is the radius of an imaginary hard sphere which can be used to model the atom for many purposes. ... You have big harry skanky balls ... In physics, magnetism is one of the phenomena by which materials exert an attractive or repulsive force on other materials. ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... The speed of sound c (from Latin celeritas, velocity) varies depending on the medium through which the sound waves pass. ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Hydrogen (H) Standard atomic mass: 1. ... Isotopes are forms of an element, therefore their nuclei have the same atomic number â€” the number of protons in the nucleus â€” but different mass numbers because they contain different numbers of neutrons. ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... In physics, the decay mode describes a particular way a particle decays. ... The decay energy is the energy released by a nuclear decay. ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... A trace radioisotope is a radioisotope that is naturally occurring. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... Latin was the language originally spoken in the region around Rome called Latium. ... The Greek language (Greek Ελληνικά, IPA // – Hellenic) is an Indo-European language with a documented history of some 3,000 years. ... A chemical element, often called simply element, is a chemical substance that cannot be decomposed or transformed into other chemical substances by ordinary chemical methods. ... The periodic table of the chemical elements is a tabular method of displaying the chemical elements, first devised in 1869 by the Russian chemist Dmitri Mendeleev. ... In chemistry and physics, the atomic number (Z) is the number of protons found in the nucleus of an atom. ... Temperature and air pressure can vary from one place to another on the Earth, and can also vary in the same place with time. ... Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionisation and bonding properties. ... It has been suggested that Valence number be merged into this article or section. ... Combustion or burning is a complex sequence of chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames. ... A computer rendering of the Nitrogen Molecule, which is a diatomic molecule. ... A gas is one of the four main phases of matter (after solid and liquid, and followed by plasma), that subsequently appear as a solid material is subjected to increasingly higher temperatures. ... To help compare different orders of magnitude we list here masses between 0. ... The deepest visible-light image of the cosmos, the Hubble Ultra Deep Field. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Water (from the Old English waeter; c. ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... The Pleiades star cluster A star is a massive, compact body of plasma in outer space that is currently producing or has produced energy through nuclear fusion. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... A Plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation A solar coronal mass ejection blasts plasma throughout the solar system. ... The expression lighter than air refers to objects, usually aircraft, that are buoyant in air because they have an average density that is less than that of air (usually because they contain gases that have a density that is lower than that of air). ... Fuel is a material with one type of energy which can be transformed into another usable energy. ... A hydrogen economy is a hypothetical future economy in which the primary form of stored energy for mobile applications and load balancing is hydrogen (H2). ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ...

Different meanings of "hydrogen"

The word "hydrogen" means different things to different people, leading to much confusion.

Possible uses:

Hydrogen is the name of an element
Hydrogen is an atom, sometimes called "H dot" that is abundant in space but essentially absent on earth, because it dimerizes.
Hydrogen is a diatomic molecule that would be a convenient fuel except that it occurs naturally only in trace amounts and must be extracted from other sources, such as fossil fuels; chemists increasingly refer to H₂ as dihydrogen to distinguish this molecule from atomic hydrogen and hydrogen found in other compounds,
Hydrogen is atomic constituent within all organic compounds, water, and many other chemical compounds.

Thus when one says that "hydrogen is ubiquitous in the universe, but surprisingly difficult to produce in large quantities on the Earth" we mean that H atoms and H₂ occur in interstellar space but that these two species are rare or expensive to generate in pure form on earth. Obviously, the earth has lots of hydrogen, but it is all bound up in molecules such as hydrocarbons and water. In the laboratory, H₂ is prepared by the reaction of acids on metals such as zinc. The electrolysis of water is a simple but expensive method of producing hydrogen. Large-scale production is usually by the process called steam reforming of natural gas. Sucrose, or common table sugar, is composed of glucose and fructose. ... Biochemistry laboratory at the University of Cologne. ... For other uses, see Acid (disambiguation). ... General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ... In chemistry and manufacturing, electrolysis is a method of separating bonded elements and compounds by passing an electric current through them. ... Steam reforming, or is called catalytic oxidation. ... Many stoves use natural gas. ...

The extraction of H₂ from water or hydrocarbons requires energy; these are endothermic processes. H₂ cannot be produced from water or hydrocarbons without the expenditure of energy, and this problem is the central quandry confronting hydrogen production. The one possibly sustainable method for production of H₂ entails photochemical water "splitting," where the input energy comes from our sun. This approach avoids production of greenhouse-gases, which are associated with fossil fuels. Certain species of green algae utilize this method under very special conditions. A second possible hydrogen production route is via the sulfur-iodine cycle using a heat source such as nuclear energy, but there are arguments about whether or not nuclear energy should be considered sustainable energy. Stripping H₂ from biomass or even purified organic compounds such as glucose or sorbitol also generate greenhouse gases, but this process (like woodburning) is not a net greenhouse producer. Endothermic can mean: In biology, an endotherm is a type of animal that can control its body temperature. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... Fossil fuels are hydrocarbon-containing natural resources such as coal, petroleum and natural gas. ... A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ... The sulfur-iodine cycle is a series of thermochemical processes used to obtain hydrogen. ... This article or section does not cite its references or sources. ... Glucose (Glc), a monosaccharide (or simple sugar), is one of the most important carbohydrates. ... Sorbitol, also known as glucitol, is a sugar alcohol the body metabolises slowly. ...

Basic features

Electronic structure

Hydrogen is the lightest chemical element; its most common isotope comprises just one negatively charged electron, distributed around a positively charged proton (the nucleus of the hydrogen atom — all other atoms have more complex nuclei involving more protons or neutrons). The electron is bound to the proton by the Coulomb force, the electrical force that one stationary, electrically charged nanoparticle exerts on another. The hydrogen atom has special significance in quantum mechanics as a simple physical system for which there is an exact solution to the Schrödinger equation; from that equation, the experimentally observed frequencies and intensities of hydrogen's spectral lines can be calculated. Spectral lines are dark or bright lines in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Isotopes are forms of an element, therefore their nuclei have the same atomic number â€” the number of protons in the nucleus â€” but different mass numbers because they contain different numbers of neutrons. ... Properties The electron is a lightweight fundamental subatomic particle that carries a negative electric charge. ... Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... A semi-accurate depiction of the helium atom. ... Properties In chemistry and physics, an atom (Greek Î¬Ï„Î¿Î¼Î¿Î½ meaning indivisible) is the smallest possible particle of a chemical element that retains its chemical properties. ... In physics, Coulombs law is an inverse-square law indicating the magnitude and direction of electrical force that one stationary, electrically charged substance of small volume (ideally, a point source) exerts on another. ... For a non-technical introduction to the topic, please see Introduction to Quantum mechanics. ... In physics, the SchrÃ¶dinger equation, proposed by the Austrian physicist Erwin SchrÃ¶dinger in 1925, is the definition of energy of a quantum system. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...

At standard temperature and pressure, hydrogen exists as the diatomic gas, H₂, with a boiling point of 20.27 K, and a melting point of 14.02 K.^{[citation needed]} Under extreme pressures, such as those at the center of gas giants, the molecules lose their identity and the hydrogen becomes a metal (metallic hydrogen). Under the extremely low pressure in space — virtually a vacuum — the element tends to exist as individual atoms, simply because it is statistically unlikely for them to combine. However, clouds of H₂ and possibly single hydrogen atoms are said to form in H I and H II regions and are associated with star formation. Hydrogen plays a vital role in powering stars through the proton–proton and carbon–nitrogen cycle. These are nuclear fusion processes, which release huge amounts of energy in stars and other hot celestial bodies as hydrogen atoms combine into helium atoms. Temperature and air pressure can vary from one place to another on the Earth, and can also vary in the same place with time. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... A gas giant is a large planet that is not composed mostly of rock or other solid matter. ... Hot metal work from a blacksmith Look up Metal in Wiktionary, the free dictionary. ... Metallic hydrogen results when hydrogen is sufficiently compressed and undergoes a phase change, and it is an example of degenerate matter. ... Look up Vacuum in Wiktionary, the free dictionary. ... An H I region is an interstellar cloud composed of warm neutral atomic hydrogen (H1). ... NGC 604, a giant H II region in the Triangulum Galaxy. ... Star formation is the process by which gas in molecular clouds change into the ball of plasma we call a star. ... For alternate meanings see star (disambiguation) Hundreds of stars are visible in this image taken by the Hubble Space Telescope of the Sagittarius Star Cloud in the Milky Way Galaxy. ... The proton-proton chain reaction is one of two fusion reactions by which stars convert hydrogen to helium, the other being the CNO cycle. ... The CNO (carbon-nitrogen_oxygen) cycle is one of two fusion reactions by which stars convert hydrogen to helium, the other being the proton-proton chain. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ...

At high temperatures, hydrogen gas can exist as a mixture of atoms, protons, and negatively charged hydride ions. This mixture has a high emissivity and absorptivity in the visible light range, and such emanations give rise to the light from the sun and other stars. The emissivity of a material (usually written ) is the ratio of energy radiated to energy radiated by a black body at the same temperature. ... In analytical chemistry, the molar absorptivity or extinction coefficient ε of a chemical species at a given wavelength is a measure of how strongly the species absorbs light at that wavelength. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... The Sun is the star at the center of our solar system. ... For alternate meanings see star (disambiguation) Hundreds of stars are visible in this image taken by the Hubble Space Telescope of the Sagittarius Star Cloud in the Milky Way Galaxy. ...

H₂ is less soluble in water, alcohol, or ether than oxygen is. Its solubility and adsorption characteristics with various metals are very important in metallurgy (as many metals can suffer hydrogen embrittlement) and in developing safe ways to store it for use as a fuel. Metallurgy is a domain of materials science and of materials engineering that studies the physical and chemical behavior of metallic elements, their intermetallic compounds and their mixtures, which are called alloys. ... Exposure to hydrogen causes various metals, most importantly steel, to become brittle and crack. ...

Combustion

Hydrogen can combust rapidly in air, as shown when the hydrogen-filled Hindenburg was destroyed on May 6, 1937.

H₂ reacts violently with chlorine and fluorine, forming the corresponding hydrogen halides, HCl and HF. In air, H₂ is highly flammable, burning at concentrations as low as 4% H₂. When mixed with oxygen, hydrogen explodes upon ignition. Uniquely, hydrogen flames are nearly invisible in air, as illustrated by the faintness of flame from the Space Shuttle engine. Thus it is difficult to visually detect if a hydrogen leak is burning. For similar reasons, it is easy to walk into a pure hydrogen fire inadvertently. Another characteristic of hydrogen fires is that they tend to rapidly lift off the ground, causing less damage than hydrocarbon fires. Two-thirds of the Hindenburg passengers survived, partly for this reason. Furthermore, it should be noted that the flames from the burning Hindenburg (seen at right) are from the covering skin, which consisted of pyrophoric aluminium powder. Image File history File links Hindenburg_burning. ... Image File history File links Hindenburg_burning. ... LZ 129 Hindenburg was a German zeppelin that was destroyed by fire while landing at Lakehurst Naval Air Station in New Jersey on May 6, 1937. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ... General Name, Symbol, Number fluorine, F, 9 Chemical series halogens Group, Period, Block 17, 2, p Appearance pale greenish-yellow gas Atomic mass 18. ... HCL or HCl can stand for: Hardware Compatibility List Chemical symbol for hydrochloric acid, written HCl Higher Chinese Language, an academic subject in Singapore An Indian software company (previously Hindustan Computers Ltd. ... HF or Hf might be an acronym or abbreviation for: High frequency Radio hafnium, a chemical element the chemical formula for Hydrofluoric acid Historisk-filosofisk fakultet, abbr. ... Combustion or burning is a complex sequence of chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames. ... The Space Shuttle Columbia seconds after engine ignition, 1981 (NASA). ... LZ 129 Hindenburg was a German zeppelin that was destroyed by fire while landing at Lakehurst Naval Air Station in New Jersey on May 6, 1937. ... LZ 129 Hindenburg was a German zeppelin that was destroyed by fire while landing at Lakehurst Naval Air Station in New Jersey on May 6, 1937. ...

The enthalpy of combustion for hydrogen is -286 kJ/mol; it combusts according to the following balanced equation.

2 H₂(g) + O₂(g) → 2 H₂O(g) + 572 kJ

See also: hydrogen atom. A hydrogen atom is an atom of the chemical element hydrogen. ...

Applications

Large quantities of H₂ are needed in the petroleum and chemical industries. By far the largest application of H₂ is for the processing ("upgrading") of fossil fuels. The key consumers of H₂ in the petrochemical plant include hydrodealkylation, hydrodesulfurization, and hydrocracking^[2]. H₂ has several other important uses. Hydrodesulfurization is one means of lowering the sulfur content of liquids from oil/coal. ... In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ...

used in the hydrogenation of fats and oils (found in items such as margarine), and in the production of methanol.
H₂ is used in the manufacture of hydrochloric acid
H₂ is used in certain welding methods
H₂ is used in the reduction of metallic ores.
H₂ is an ingredient in some rocket fuels.
H₂ is used as the rotor coolant in electrical generators at power stations, because it has the highest thermal conductivity of any gas.
Liquid H₂ is used in cryogenic research, including superconductivity studies.
The triple point temperature of equilibrium hydrogen is a defining fixed point on the ITS-90 temperature scale.
Since H₂ is lighter than air, having a little more than 1/15th of the density of air, it was once widely used as a lifting agent in balloons and airships. However, this use was curtailed after the Hindenburg disaster convinced the public that the gas was too dangerous for this purpose.
Deuterium, an isotope of hydrogen (hydrogen-2), is used in nuclear fission applications as a moderator to slow neutrons, and in nuclear fusion reactions. Deuterium compounds have applications in chemistry and biology in studies of reaction isotope effects.
Tritium (hydrogen-3), produced in nuclear reactors, is used in the production of hydrogen bombs, as an isotopic label in the biosciences, and as a radiation source in luminous paints.

Hydrogenation is a chemical reaction in which unsaturated bonds between carbon atoms are reduced by attachment of a hydrogen atom to each carbon. ... This article or section is in need of attention from an expert on the subject. ... It has been suggested that this article or section be merged with cooking oil. ... Margarine, as a generic term, can indicate any of a wide range of butter-substitutes. ... Methanol, also known as methyl alcohol or wood alcohol, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a very faint odor. ... The chemical compound hydrochloric acid is the aqueous (water-based) solution of hydrogen chloride (HCl) gas. ... Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. ... Iron ore (Banded iron formation) Manganese ore Lead ore Gold ore An ore is a volume of rock containing components or minerals in a mode of occurrence which renders it valuable for mining. ... Rocket fuel is a propellant that reacts with an oxidizing agent to produce thrust in a rocket. ... An electrical generator is a device that produces electrical energy from a mechanical energy source. ... Oil power plant in Iraq A power station or power plant is a facility for the generation of electric power. ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... Cryogenics is the study of very low temperatures or the production of the same, and is often confused with cryobiology, the study of the effect of low temperatures on organisms, or the study of cryopreservation. ... A high-temperature superconductor levitating above a magnet (with boiling liquid nitrogen underneath) demonstrates the Meissner effect. ... In physics, the triple point of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium. ... The International Temperature Scale of 1990 (ITS-90) is an equipment calibration standard for making measurements on the kelvin and Celsius temperature scales. ... The expression lighter than air refers to objects, usually aircraft, that are buoyant in air because they have an average density that is less than that of air (usually because they contain gases that have a density that is lower than that of air). ... Balloons are a type of lighter than air aircraft that remain aloft due to their buoyancy. ... USS Akron (ZRS-4) in flight, November 2, 1931 An airship is a buoyant aircraft that can be steered and propelled through the air. ... LZ 129 Hindenburg was a German zeppelin that was destroyed by fire while landing at Lakehurst Naval Air Station in New Jersey on May 6, 1937. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of one atom in 6400 of hydrogen (see VSMOW; the abundance changes slightly from one kind of natural water to another). ... The CANDU reactor is a Pressurized Heavy Water Reactor developed initially in the late 1950s and 1960s by a partnership between Atomic Energy of Canada Limited (AECL), the Hydro-Electric Power Commission of Ontario (now known as Ontario Power Generation), Canadian General Electric (now known as GE Canada), as well... In nuclear engineering, a neutron moderator is a medium which reduces the velocity of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Chemistry (derived from alchemy) is the science of matter at or near the atomic scale. ... Biology is the branch of science dealing with the study of life. ... hey!! I hate you!! isotopes are the elements that have different no. ... Tritium (symbol T or 3H) is a radioactive isotope of hydrogen. ... Core of a small nuclear reactor used for research. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, in 1945 lifted nuclear fallout some 18 km (60,000 feet) above the epicenter. ... Beta particles are high-energy electrons emitted by certain types of radioactive nuclei such as potassium-40. ...

Hydrogen as an energy source

Hydrogen is not a pre-existing source of energy like fossil fuels, but a carrier, much like a battery. There are no "hydrogen wells" or "hydrogen mines" on Earth, so H₂ cannot be considered a primary energy source such as fossil fuels or uranium. Since H₂ is so light, any amount present on earth will float up into the atmosphere and out into space. H₂ can however be burned in internal combustion engines, an approach advocated by BMW's experimental hydrogen car. There are several methods of storing hydrogen for transport applications, the most commonly-used being gaseous storage in gas cylinders similar to those used for the storage of any pressurised gas. Alternatives include storage as metal or chemical hydrides, cryogenic storage of liquid hydrogen (as in BMW's hydrogen internal combustion engine car) and research points to nanomaterials that will be able to store hydrogen more efficiently than any of the methods above. Fossil fuels are hydrocarbon-containing natural resources such as coal, petroleum and natural gas. ... This article or section does not cite its references or sources. ... Coal rail cars in Ashtabula, Ohio Fossil fuels, also known as mineral fuels, are hydrocarbon-containing natural resources such as coal, oil and natural gas. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ... A colorized automobile engine The internal combustion engine is a heat engine in which the burning of a fuel occurs in a confined space called a combustion chamber. ... It has been suggested that this article or section be merged with Hydrogen vehicle. ...

$Emission spectrum of an ultraviolet deuterium arc lamp clearly showing characteristic hydrogen emission lines (sharp peaks at 656 nm and 486 nm) and continuum emission in the ~200-400 nm region. The emission spectrum of deuterium differs from that of protium due to the influence of hyperfine interactions, though these effects alter the wavelength of the lines by mere fractions of a nanometer and are too fine to be discerned by the spectrometer used here.$

Emission spectrum of an ultraviolet deuterium arc lamp clearly showing characteristic hydrogen emission lines (sharp peaks at 656 nm and 486 nm) and continuum emission in the ~200-400 nm region. The emission spectrum of deuterium differs from that of protium due to the influence of hyperfine interactions, though these effects alter the wavelength of the lines by mere fractions of a nanometer and are too fine to be discerned by the spectrometer used here.

Hydrogen fuel cells are being investigated as mobile power sources with lower emissions than hydrogen-burning internal combustion engines. The low emissions of hydrogen in internal combustion engines and fuel cells are currently offset by the pollution created by hydrogen production. This may change if the substantial amounts of electricity required for water electrolysis can be generated primarily from low pollution sources such as solar energy or wind. Research is being conducted on H₂ as a replacement for fossil fuels. It could become the link between a range of energy sources, carriers and storage. H₂ can be converted to and from electricity (solving the electricity storage and transport issues), from biofuels, and from and into natural gas and diesel fuel. All of this can theoretically be achieved with zero emissions of CO₂ and toxic pollutants. (See also Hydrogen economy.) Image File history File links Download high resolution version (2715x1816, 68 KB) Summary Spectrum of a deuterium lamp taken with an Ocean Optics HR4000 spectrometer [1] using a high-OH solarization-resistant fiber optic. ... Image File history File links Download high resolution version (2715x1816, 68 KB) Summary Spectrum of a deuterium lamp taken with an Ocean Optics HR4000 spectrometer [1] using a high-OH solarization-resistant fiber optic. ... Emission spectrum of an ultraviolet deuterium arc lamp clearly showing characteristic hydrogen emission lines (sharp peaks at 656 nm and 486 nm) and continuum emission in the ~160-400 nm region. ... Hyperfine structure is a small perturbation in the energy levels (or spectral) of atoms due to the proton-electron dipole moment interaction. ... A nanometre (American spelling: nanometer) is 1. ... // Headline text Bold text:For Acoustic uses in spectrographs of sound waves, see below. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... In physics, power (symbol: P) is the amount of work done per unit of time. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... In chemistry and manufacturing, electrolysis is a method of separating bonded elements and compounds by passing an electric current through them. ... Biofuel is any fuel that derives from biomass â€” recently living organisms or their metabolic byproducts, such as manure from cows. ... Many stoves use natural gas. ... Diesel or Diesel fuel is a specific fractional distillate of fuel oil (mostly petroleum) that is used as fuel in a diesel engine invented by German engineer Rudolf Diesel. ... A hydrogen economy is a hypothetical future economy in which the primary form of stored energy for mobile applications and load balancing is hydrogen (H2). ...

In the Haber process for the production of ammonia and the world's fifth most produced industrial compound, hydrogen is generated in situ from natural gas. The Haber Process (also Haber-Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... Ammonia is a compound of nitrogen and hydrogen with the formula NH3. ...

History

Discovery of H₂

H₂ was first produced by Theophrastus Bombastus von Hohenheim (1493–1541)—also known as Paracelsus—by mixing metals with acids. He was unaware that the inflammable gas produced by this chemical reaction was H₂. In 1671, Robert Boyle described the reaction between iron filings and dilute acids, which results in the production of H₂.^[3] In 1766, Henry Cavendish was the first to recognize H₂ as a discrete substance, by identifying the gas from this reaction as "inflammable" and finding that the gas produces water when burned in air. Cavendish stumbled on H₂ when experimenting with acids and mercury. Although he wrongly assumed that hydrogen was a compound of mercury—and not of the acid—he was still able to accurately describe several key properties of hydrogen. 1493 was a common year starting on Sunday (see link for calendar) of the Gregorian calendar. ... Events The first official translation of the entire Bible in Swedish February 12 - Pedro de Valdivia founds Santiago de Chile. ... Paracelsus Paracelsus (November 11 or December 17, 1493 - September 24, 1541) was a famous alchemist, physician, astrologer, and general occultist. ... Robert Boyle The Honourable Robert Boyle (January 25, 1627 - December 30, 1691) was an Irish natural philosopher, noted for his work in physics and chemistry. ... 1766 was a common year starting on Wednesday (see link for calendar). ... Henry Cavendish (October 10, 1731 - February 24, 1810) was a British scientist. ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery white Atomic mass 200. ... For other uses, see Acid (disambiguation). ...

Antoine Lavoisier gave the element its name and proved that water is composed of hydrogen and oxygen. One of the first uses of H₂ was for balloons. The H₂ was obtained by reacting sulfuric acid and metallic iron. Antoine-Laurent de Lavoisier (August 26, 1743 â€“ May 8, 1794) was a French nobleman prominent in the histories of chemistry, finance, biology, and economics. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Balloons, like greeting cards or flowers, are given for special occasions. ... Sulfuric acid (British English: sulphuric acid), H2SO4, is a strong mineral acid. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ...

Because of its relatively simple atomic structure, consisting only of a proton and an electron, the hydrogen atom has been central to the development of the theory of atomic structure. Properties In chemistry and physics, an atom (Greek Î¬Ï„Î¿Î¼Î¿Î½ meaning indivisible) is the smallest possible particle of a chemical element that retains its chemical properties. ...

Isotopes of hydrogen

In 1931, Harold C. Urey discovered deuterium, an isotope of hydrogen, by spectrographic study of the last residual milliliter after evaporation of 5 liters of cryogenically-produced liquid hydrogen. Urey was also able to concentrate deuterium in water by repeated fractional distillation. For the discovery of deuterium Urey received the Nobel Prize in Chemistry in 1934. In the same year, the discovery of the third isotope, tritium, was announced. Harold Urey, circa 1963. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of one atom in 6400 of hydrogen (see VSMOW; the abundance changes slightly from one kind of natural water to another). ... Isotopes are forms of an element, therefore their nuclei have the same atomic number â€” the number of protons in the nucleus â€” but different mass numbers because they contain different numbers of neutrons. ... This is a list of Nobel Prize laureates in Chemistry from 1901 to the present day. ... Tritium (symbol T or 3H) is a radioactive isotope of hydrogen. ...

Electron energy levels

The ground state energy level of the electron in a hydrogen atom is 13.6 eV, which is equivalent to an ultraviolet photon of roughly 92 nm. In physics, the ground state of a quantum mechanical system is its lowest-energy state. ... A quantum mechanical system can only be in certain states, so that only certain energy levels are possible. ... The electronvolt (symbol eV, or, rarely and incorrectly, ev) is a unit of energy. ... metre or meter, see meter (disambiguation) The metre (in the U.S., chiefly meter) is a measure of length, approximately equal to 3. ...

With the Bohr Model the energy levels of hydrogen can be calculated fairly accurately. This is done by modeling the electron as revolving around the proton, much like the earth revolving around the sun, except that the sun holds earth in orbit with the force of gravity, but the proton holds the electron in orbit with the force of electromagnetism. Another difference between the Earth-Sun system and the electron-proton system is that, in this model, due to quantum mechanics the electron is allowed to only to be at very specific distances from the proton. Today, the hydrogen atom is most accurately described today by the use of a pure quantum mechanical model. This model uses Schrodinger's wave equation to calculate the probability density of the electron around the nucleus in a H-atom. Since the electron is treated not as a particle but as a matter wave, its dual properties gel very well with supposedly paradoxical results obtained by experiments which are unexplainable under Bohr Model. The wave features of electron are again well explained by de Broglie's equation hv = mV. This equation relates v (frequency of the electron matter wave) to mV (the momentum of the material electron). In this way, electrons are treated at different times as either matter and as a wave, depending on the needs of the model. Modeling the hydrogen atom in this fashion yields the correct energy levels and spectrum. As an added feature, modeling the system fully using the reduced mass of nucleus and electron (as one would do in the two-body problem in celestial mechanics) yields an even better formula for the hydrogen spectra, and also the correct spectral shifts for the isotopes deuterium and tritium, which are induced by changes only in this parameter. The Bohr model of the atom In 1913, Niels Bohr introduced what has become known as the Bohr model of the atom to atomic physics. ... Gravity is a force of attraction that acts between bodies that have mass. ... Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, which exerts a force on those particles that possess the property of electric charge, and is in turn affected by the presence and motion of such particles. ... For a non-technical introduction to the topic, please see Introduction to Quantum mechanics. ... Reduced mass is a concept that allows one to solve the two-body problem of mechanics as if it were a one body problem. ... In mechanics, the two-body problem is a special case of the n-body problem that admits a closed form solution. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of one atom in 6400 of hydrogen (see VSMOW; the abundance changes slightly from one kind of natural water to another). ... Tritium (symbol T or 3H) is a radioactive isotope of hydrogen. ...

The electronic ground state energy level is split into hyperfine structure levels because of magnetic effects due to the quantum mechanical spin of the electron and proton. The energy of the atom when the proton and electron spins are aligned is 5.9 x 10^-6 eV higher than when they are not aligned. The transition from the upper to lower levels can occur through emission of a photon through a magnetic dipole transition. A photon of this energy has a frequency of 1420.4 MHz and a wavelength of 21.1 cm. Astronomers observe this radiation with radio telescopes in order to map the distribution of hydrogen in the Galaxy. In physics, the ground state of a quantum mechanical system is its lowest-energy state. ... A quantum mechanical system can only be in certain states, so that only certain energy levels are possible. ... In atomic physics, hyperfine structure is a small perturbation in the energy levels (or spectrum) of atoms or molecules due to the magnetic dipole-dipole interaction, arrising from the interaction of the nuclear magnetic dipole with the magnetic field of the electron. ... Fig. ... This article is about the electromagnetic phenomenon. ...

Occurrence

NGC 604, a giant H II region in the Triangulum Galaxy.

Hydrogen is the most abundant element in the universe, making up 75% of normal matter by mass and over 90% by number of atoms. ^[4] This element is found in great abundance in stars and gas giant planets. However, it is very rare in the Earth's atmosphere (1 ppm by volume). Its scarcity is due to the fact that hydrogen is the lightest gas, allowing it to escape Earth's gravity. When compounds are included, though, hydrogen is the tenth most abundant element on Earth. The most common source for this element on Earth is water, which is composed two parts hydrogen to one part oxygen (H₂O). Other sources include most forms of organic matter including coal, natural gas, and other fossil fuels. Methane (CH₄) is an increasingly important source of hydrogen. Download high resolution version (1127x1201, 2479 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1127x1201, 2479 KB) Wikipedia does not have an article with this exact name. ... Categories: Astronomy stubs | Nebulae | NGC objects ... Messier Object 33, the Triangulum Galaxy. ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... Mass is a property of a physical object that quantifies the amount of matter and energy it contains. ... Properties In chemistry and physics, an atom (Greek Î¬Ï„Î¿Î¼Î¿Î½ meaning indivisible) is the smallest possible particle of a chemical element that retains its chemical properties. ... The Pleiades star cluster A star is a massive, compact body of plasma in outer space that is currently producing or has produced energy through nuclear fusion. ... Earth (often referred to as The Earth) is the third planet in the solar system in terms of distance from the Sun, and the fifth in order of size. ... Parts per million (ppm) is a measure of concentration that is used where low levels of concentration are significant. ... A chemical compound is a chemical substance formed from two or more elements, with a fixed ratio determining the composition. ... Water (from the Old English waeter; c. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Coal (previously referred to as pitcoal or seacoal) is a fossil fuel extracted from the ground by underground mining or open-pit mining (surface mining). ... Many stoves use natural gas. ... Coal rail cars in Ashtabula, Ohio Fossil fuels, also known as mineral fuels, are hydrocarbon-containing natural resources such as coal, oil and natural gas. ... The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ...

Throughout the universe, hydrogen is mostly found in the plasma state whose properties are quite different from molecular hydrogen. As a plasma, hydrogen's electron and proton are not bound together, resulting in very high electrical conductivity. The charged particles are highly influenced by magnetic and electric fields. For example, in the solar wind they interact with the Earth's magnetosphere giving rise to Birkeland currents and the aurora. A Plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation A solar coronal mass ejection blasts plasma throughout the solar system. ... The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... Schematic of Earths magnetosphere. ... The aurora on Jupiter, powered by Jovian Birkeland currents [Ref. ... Aurora borealis Aurora borealis The aurora is a glow observed in the night sky, usually in the polar zone. ...

Production

Hydrogen can be prepared in several different ways but the economically most important processes involve removal of hydrogen from hydrocarbons. Commercial bulk hydrogen is usually produced by the steam reforming of natural gas. At high temperatures (700–1100 °C), steam (water vapor) reacts with methane to yield carbon monoxide and H₂. Steam reforming, or is called catalytic oxidation. ... Many stoves use natural gas. ... Carbon monoxide, chemical formula CO, is a colorless, odorless, tasteless, flammable and highly toxic gas. ...

CH₄ + H₂O → CO + 3 H₂

This reaction is favored at low pressures but is nonetheless conducted at high pressures (20 atm) since high pressure H₂ is the most marketable product. One of the many complications to this very optimized technology is the formation of coke or carbon: The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ... Water (from the Old English waeter; c. ... Carbon monoxide, chemical formula CO, is a colorless, odorless, tasteless, flammable and highly toxic gas. ...

CH₄ → C + 2 H₂

Consequently, steam reforming typically employs an excess of H₂O. The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ...

Additional hydrogen from steam reforming can be recovered from the carbon monoxide through the Water gas shift reaction: The water gas shift reaction is an organic reaction in which water and carbon monoxide react to form carbon dioxide and hydrogen (water splitting) CO + H2O â†’ CO2 + H2 The water gas shift reaction is part of steam reforming of hydrocarbons and is involved in the chemistry of catalytic converters While...

CO + H₂O → CO₂ + H₂

Other important methods for H₂ production include partial oxidation of hydrocarbons: Carbon monoxide, chemical formula CO, is a colorless, odorless, tasteless, flammable and highly toxic gas. ... Water (from the Old English waeter; c. ... Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ...

CH₄ + 0.5 O₂ → CO + 2 H₂

and water electrolysis. The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Carbon monoxide, chemical formula CO, is a colorless, odorless, tasteless, flammable and highly toxic gas. ... In chemistry and manufacturing, electrolysis is a method of separating bonded elements and compounds by passing an electric current through them. ...

In the laboratory, H₂ can be generated by treatment of many metals with acids or base.

Zn + 2 H⁺ → Zn²⁺ + H₂

2 Al + 6 H₂O → 2 Al(OH)₃ + 3 H₂

General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ...

Compounds

Hydrogen forms compounds with most other elements, although interestingly H₂ does not directly react with most common elements. For example, millions of hydrocarbons are known, but none arise from direct reactions of hydrogen and carbon. Hydrogen with an electronegativity of 2.2 (Pauling's scale) forms compounds with elements that are both more electronegative such as halogens (F, Cl, Br, I) and chalcogens (O, S, Se). It also forms compounds with elements that are less electronegative, such as the metals and metalloids. Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The halogens The halogens are a chemical series. ... The chalcogens (with the ch pronounced with a hard c as in chemistry) are the name for the periodic table group 16 (old-style: VIB or VIA) in the periodic table. ...

Hydrides

Many compounds of hydrogen are called hydrides, but the term is used fairly loosely. To chemists, the term "hydride" usually implies that the H atom has acquired a negative charge, H⁻-like. The hydride ion itself, H⁻, exists only in few compounds such as alkali metals hydrides. In fact in 1920, K. Moers demonstrated that electrolysis of molten lithium hydride LiH (m.p. 692 °C) produced the stoichiometric quantity of hydrogen at the anode. Well known hydrides include NaH, an ionic solid, and lithium aluminum hydride, a salt containing the AlH₄⁻ complex anion. Palladium hydride contains insterstitial hydrogen atoms, i.e. the H atoms are bonded to multiple Pd atoms without perturbing the overall Pd framework. Hydrogen forms hydrides with all main group elements with the exception of the noble gases and indium and thallium. A hydride is a compound of hydrogen with more electropositive elements. ... Palladium hydride is metallic palladium that contains a substantial quantity of hydrogen within its crystal lattice. ...

Protons

Oxidation of H₂ formally gives the proton, H⁺. The proton is central to discussions of acids and the term proton is loosely used to refer to hydrogen with H⁺-like character. Being a bare nucleus, H⁺ cannot exist in solution; it would have a strong tendency to attach itself to atoms or molecules with electrons. In acknowledgement of the non-existence of H⁺, chemists sometimes discuss acidic aqueous solutions in the context of hydronium (H₃O⁺). Even the hydronium ion is a poor representation of the "solvated proton"; H₉O₄⁺ is a better description. For other uses, see Acid (disambiguation). ... In chemistry, hydronium is the common name for the cation H3O+ derived from protonation of water. ...

Although exotic on earth, one of the most common ions in the universe is the H₃⁺ ion. Protonated moleclular hydrogen, or H3+, is the most abundant ion in the universe, the second being CH5+. Although less stable than its constitutent parts, H2, and H+, it persists because in the sparseness of space, there are no other molecules or atoms to which it can transfer energy and undergo...

H₂ reacts with oxygen to form water, H₂O. Considerable energy is released in this process. No reaction occurs between H₂ and O₂ in the absence of a catalyst or a flame. Deuterium oxide, or D₂O, is commonly referred to as heavy water. Hydrogen also forms a vast array of compounds with carbon. Because of their association with living things, these compounds are called organic compounds, and their study is called organic chemistry. (Strictly speaking, organic compounds are only required to contain carbon; however most of them also contain hydrogen). Water (from the Old English waeter; c. ... Heavy water is dideuterium oxide, or D2O or 2H2O. It is chemically the same as normal water, H2O, but the hydrogen atoms are of the heavy isotope deuterium, in which the nucleus contains a neutron in addition to the proton found in the nucleus of any hydrogen atom. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... Benzene An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with the exception of carbides, carbonates, carbon oxides and elementary carbon. ... Organic chemistry is the part of chemistry concerned with the composition, structure, properties, reactions and synthesis of organic compounds. ...

First tracks observed in liquid hydrogen bubble chamber.

See also hydrogen compounds. Download high resolution version (640x852, 62 KB)First tracks observed in liquid hydrogen bubble chamber by John Wood, 1954. ... Download high resolution version (640x852, 62 KB)First tracks observed in liquid hydrogen bubble chamber by John Wood, 1954. ...

Forms

Under normal conditions, hydrogen gas is a mixture of two different kinds of molecules which differ from one another by the relative spin of the nuclei.^[5] These two forms are known as ortho- and para-hydrogen (this is different from isotopes, see below). In ortho-hydrogen the nuclear spins are parallel and form a triplet, whereas in the para form. the spins are antiparallel, giving rise to a singlet. At standard conditions hydrogen is composed of about 25% of the para form and 75% of the ortho form (the so-called "normal" form). The equilibrium ratio of these two forms depends on temperature, but since the ortho form has higher energy (is an excited state), it cannot be stable in its pure form. At low temperatures (around boiling point), the equilibrium state is comprised almost entirely of the para form. In chemistry, a molecule is an aggregate of at least two atoms in a definite arrangement held together by special forces. ... In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is generated by the motion of its center of mass about an external point. ... A semi-accurate depiction of the helium atom. ... Isotopes are forms of an element, therefore their nuclei have the same atomic number â€” the number of protons in the nucleus â€” but different mass numbers because they contain different numbers of neutrons. ... Temperature and air pressure can vary from one place to another on the Earth, and can also vary in the same place with time. ... It has been suggested that this article or section be merged with quantum state. ...

The uncatalized interconversion between para and ortho H₂ is slow enough that rapidly condensed H₂ contains large quantities of the high-energy ortho form. The ortho/para ratio is important in the preparation and storage of liquid H₂, since the ortho-para conversion produces more heat than the heat of its evaporation, which can cause much hydrogen to be lost by evaporation in this way for several days after liquefying. Therefore, catalysts for the ortho-para interconversion process (such as iron filings) are used during hydrogen cooling. The two forms have also slightly different physical properties. For example, the melting and boiling points of parahydrogen are about 0.1 K lower than of the "normal" form. In chemistry, a catalyst (Greek: ÎºÎ±Ï„Î±Î»ÏÏ„Î·Ï‚, catalytÄ“s) is a substance that accelerates the rate (speed) or ease of a chemical reaction (see also catalysis) without itself being changed at the end of the chemical reaction. ...

Elemental hydrogen can exist in over 50 different forms, arising from either ionized species such H⁺, H⁻, H²⁺…H^1- , or from the three isotopes: H-1, H-2(D), H-3(T), and their corresponding ions which also include H with different nuclear spin isomers.

Isotopes

Main article: Isotopes of hydrogen

Hydrogen is the only element that has different names for its isotopes. (During the early study of radioactivity, various heavy radioactive isotopes were given names, but such names are no longer used, although one element, radon, has a name that originally applied to only one of its isotopes.) The symbols D and T (instead of ²H and ³H) are sometimes used for deuterium and tritium, although this is not officially sanctioned. (The symbol P is already in use for phosphorus and is not available for protium.) Hydrogen (H) Standard atomic mass: 1. ... General Name, Symbol, Number radon, Rn, 86 Chemical series noble gases Group, Period, Block 18, 6, p Appearance colorless Atomic mass (222) g/mol Electron configuration [Xe] 4f14 5d10 6s2 6p6 Electrons per shell 2, 8, 18, 32, 18, 8 Physical properties Phase gas Melting point 202 K (-71 Â°C... This article is about the chemical element. ...

¹H

The most common isotope of hydrogen, this stable isotope has a nucleus consisting of a single proton; hence the descriptive, although rarely used, name protium. The spin of a protium atom is 1/2+. ^[6] A semi-accurate depiction of the helium atom. ... Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... Protium can be several things: In chemistry, protium is the most common isotope of the element hydrogen; that has one proton and no neutrons. ... In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is generated by the motion of its center of mass about an external point. ...

²H

The other stable isotope is deuterium, with an extra neutron in the nucleus. Deuterium comprises 0.0184%–0.0082% of all hydrogen on Earth (IUPAC); ratios of deuterium to protium are reported relative to the VSMOW standard reference water. The spin of a deuterium atom is 1+. Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of one atom in 6400 of hydrogen (see VSMOW; the abundance changes slightly from one kind of natural water to another). ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... The International Union of Pure and Applied Chemistry (IUPAC) is an international non-governmental organization devoted to the advancement of chemistry. ... // Overview of VSMOW VSMOW, or Vienna Standard Mean Ocean Water, is a standard defined in 1968 by the International Atomic Energy Agency. ...

³H

The third naturally occurring hydrogen isotope is the radioactive tritium. The tritium nucleus contains two neutrons in addition to the proton. It decays through beta decay and has a half-life of 12.32 years. Tritium occurs naturally due to cosmic rays interacting with atmospheric gases. Like ordinary hydrogen, tritium reacts with the oxygen in the atmosphere to form T₂O. This radioactive "water" molecule constantly enters the Earth's seas and lakes in the form of slightly radioactive rain, but its half-life is short enough to prevent a buildup of hazardous radioactivity. The spin of a tritium atom is 1/2+. Tritium (symbol T or 3H) is a radioactive isotope of hydrogen. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ...

⁴H

Hydrogen-4 was synthesized by bombarding tritium with fast-moving deuterium nuclei. It decays through neutron emission and has a half-life of 9.93696x10⁻²³ seconds. The spin of a hydrogen-4 atom is 2-. Hydrogen (H) Standard atomic mass: 1. ... Neutron emission is a type of radioactive decay in which an atom contains excess neutrons and a neutron is simply ejected from the nucleus. ... Look up second in Wiktionary, the free dictionary. ...

⁵H

In 2001 scientists detected hydrogen-5 by bombarding a hydrogen target with heavy ions. It decays through neutron emission and has a half-life of 8.01930x10⁻²³ seconds. Hydrogen (H) Standard atomic mass: 1. ... Neutron emission is a type of radioactive decay in which an atom contains excess neutrons and a neutron is simply ejected from the nucleus. ... Look up second in Wiktionary, the free dictionary. ...

⁶H

Hydrogen-6 decays through triple neutron emission and has a half-life of 3.26500x10⁻²² seconds. Hydrogen (H) Standard atomic mass: 1. ... Neutron emission is a type of radioactive decay in which an atom contains excess neutrons and a neutron is simply ejected from the nucleus. ... Look up second in Wiktionary, the free dictionary. ...

⁷H

In 2003 hydrogen-7 was created (article) at the RIKEN laboratory in Japan by colliding a high-energy beam of helium-8 atoms with a cryogenic hydrogen target and detecting tritons—the nuclei of tritium atoms—and neutrons from the breakup of hydrogen-7, the same method used to produce and detect hydrogen-5. Hydrogen (H) Standard atomic mass: 1. ...

Biology of the free element

Scientists from the University of Colorado at Boulder discovered in 2005 that some microbes living in the hot waters of Yellowstone National Park gain their sustenance from molecular hydrogen. The CU Boulder campus. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... For the next-generation airliner series from Boeing, see Boeing Yellowstone Project. ...

References

^ Hydrogen in the Universe, NASA Website. URL accessed on 2 June 2006.
^ Los Alamos National Laboratory – Hydrogen. Retrieved on September 15, 2005.
^ Webelements – Hydrogen historical information. Retrieved on September 15, 2005.
^ Jefferson Lab – Hydrogen. Retrieved on September 15, 2005.
^ Universal Industrial Gases, Inc. – Hydrogen (H₂) Applications and Uses. Retrieved on September 15, 2005.
^ Lawrence Berkeley National Laboratory – Hydrogen isotopes. Retrieved on September 15, 2005.

RIKEN Beam Science Laboratory, Japan — Heavy hydrogen research
Nuclides and Isotopes Fourteenth Edition: Chart of the Nuclides, General Electric Company, 1989

Book references

Stwertka, Albert (2002). A Guide to the Elements. New York, NY: Oxford University Press. ISBN 0195150279.
Krebs, Robert E. (1998). The History and Use of Our Earth's Chemical Elements : A Reference Guide. Westport, Conn.: Greenwood Press. ISBN 0313301239.
Newton, David E. (1994). The Chemical Elements. New York, NY: Franklin Watts. ISBN 0531125017.
Rigden, John S. (2002). Hydrogen : The Essential Element. Cambridge, MA: Harvard University Press. ISBN 0531125017.
Joseph J. Romm (2004). The Hype about Hydrogen, Fact and Fiction in the Race to Save the Climate. Island Press. ISBN 155963703X. Author interview at Global Public Media.

Other references

"New Trends in Reforming Technologies: from Hydrogen Industrial Plants to Multifuel Microreformers" P. Ferreira-Aparicio, M. J. Benito, J. L. Sanz Catalysis Reviews, volume 47, pages 491–588, 2005. June 2 is the 153rd day of the year in the Gregorian calendar (154th in leap years), with 212 days remaining. ... 2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ... September 15 is the 258th day of the year (259th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... September 15 is the 258th day of the year (259th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... September 15 is the 258th day of the year (259th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... September 15 is the 258th day of the year (259th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... September 15 is the 258th day of the year (259th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... Dr. Joseph J. Romm was born on June 27, 1960 in Middletown, New York. ... The Hype about Hydrogen, Fact and Fiction in the Race to Save the Climate is a book by Joseph J. Romm, published in 2004 (ISBN 155963703X). ...

External links

Look up hydrogen in
Wiktionary, the free dictionary.

Wikimedia Commons has media related to:

Hydrogen

Hydrogen phase diagram.
Computational Chemistry Wiki
Basic Hydrogen Calculations of Quantum Mechanics
wavefunction of hydrogen
Biohydrogen.

For a full list of external links, MSDSs, and suppliers of chemical compounds, see Wikipedia:Chemical sources. Wikipedia does not have an article with this exact name. ... Wiktionary is a Wikimedia Foundation project intended to be a free wiki dictionary (hence: Wiktionary) (including thesaurus and lexicon) in every language. ... Image File history File links Commons-logo. ... Wikimedia Commons logo by Reid Beels The Wikimedia Commons (also called Commons or Wikicommons) is a repository of free content images, sound and other multimedia files. ... This page meets Wikipedias criteria for speedy deletion. ...

Categories: Articles with unsourced statements | Hydrogen | Chemical elements | Nonmetals

COMMENTARY

Share your thoughts, questions and commentary here

Want to know more?
Search encyclopedia, statistics and forums:

Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m

Contents

Different meanings of "hydrogen" GA_googleFillSlot("encyclopedia_square");