Hydrogen

context: Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 7000100794000000000♠1.00794 u, hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass.[note 1] Non-remnant stars are mainly composed of hydrogen in its plasma state. The most common isotope of hydrogen, termed protium (name rarely used, symbol 1H), has one proton and no neutrons.
qas: answers: text: H
question: What is hydrogens chemical symbol?

answers: text: 1
question: What is the atomic number used for hydrogen?

answers: text: 7000100794000000000♠1.00794 u
question: What is the atomic weight for hydrogen?

answers: text: Hydrogen
question: What element is considered the lightest?

context: The universal emergence of atomic hydrogen first occurred during the recombination epoch. At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, highly combustible diatomic gas with the molecular formula H2. Since hydrogen readily forms covalent compounds with most non-metallic elements, most of the hydrogen on Earth exists in molecular forms such as in the form of water or organic compounds. Hydrogen plays a particularly important role in acid–base reactions as many acid-base reactions involve the exchange of protons between soluble molecules. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) when it is known as a hydride, or as a positively charged (i.e., cation) species denoted by the symbol H+. The hydrogen cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds are always more complex species than that would suggest. As the only neutral atom for which the Schrödinger equation can be solved analytically, study of the energetics and bonding of the hydrogen atom has played a key role in the development of quantum mechanics.
qas: answers: text: molecular
question: What form can you find hydrogen is on Earth?

answers: text: H2
question: What is the molecular make-up of hydrogen?

answers: text: colorless, odorless, tasteless
question: What are three properties of hydrogen at normal temperature and normal pressure?

answers: text: negative
question: What charge does hydrogen display in ionic compounds when it is called a hydride?

answers: text: quantum mechanics
question: What field of study has hydrogen and it's properties played a key role in development?

context: Hydrogen gas was first artificially produced in the early 16th century, via the mixing of metals with acids. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, a property which later gave it its name: in Greek, hydrogen means "water-former".
qas: answers: text: early 16th century
question: When was hydrogen gas artificially produced for the first time?

answers: text: Henry Cavendish
question: Who first recognized that hydrogen was a discrete substance?

answers: text: water
question: When it is burned what does hydrogen make?

answers: text: water-former
question: What is the Greek translation for hydrogen?

context: Industrial production is mainly from the steam reforming of natural gas, and less often from more energy-intensive hydrogen production methods like the electrolysis of water. Most hydrogen is employed near its production site, with the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production, mostly for the fertilizer market. Hydrogen is a concern in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks.
qas: answers: text: the fertilizer market
question: What market primarily uses ammonia production?

answers: text: hydrocracking
question: Name a process that uses fossil fuels along with hydrogen.

context: Hydrogen gas (dihydrogen or molecular hydrogen) is highly flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume. The enthalpy of combustion for hydrogen is −286 kJ/mol:
qas: answers: text: 286 kJ/mol
question: For hydrogen what is the enthalpy of combustion?

answers: text: dihydrogen or molecular hydrogen
question: What are two forms of hydrogen gas?

answers: text: Hydrogen
question: Which element has a enthalpy of combustion at −286 kJ/mol?

context: Hydrogen gas forms explosive mixtures with air if it is 4–74% concentrated and with chlorine if it is 5–95% concentrated. The mixtures may be ignited by spark, heat or sunlight. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 °C (932 °F). Pure hydrogen-oxygen flames emit ultraviolet light and with high oxygen mix are nearly invisible to the naked eye, as illustrated by the faint plume of the Space Shuttle Main Engine compared to the highly visible plume of a Space Shuttle Solid Rocket Booster. The detection of a burning hydrogen leak may require a flame detector; such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames. The destruction of the Hindenburg airship was an infamous example of hydrogen combustion; the cause is debated, but the visible orange flames were the result of a rich mixture of hydrogen to oxygen combined with carbon compounds from the airship skin.
qas: answers: text: ultraviolet light
question: What kind of light do hydrogen-oxygen flames make?

answers: text: hydrogen combustion
question: What caused  the Hindenburg to explode?

context: H2 reacts with every oxidizing element. Hydrogen can react spontaneously and violently at room temperature with chlorine and fluorine to form the corresponding hydrogen halides, hydrogen chloride and hydrogen fluoride, which are also potentially dangerous acids.
qas: answers: text: hydrogen chloride and hydrogen fluoride
question: What are two other dangerous acids?

answers: text: room temperature
question: What temperature does hydrogen react with these elements?

context: The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, which conceptualizes the electron as "orbiting" the proton in analogy to the Earth's orbit of the Sun. However, the electromagnetic force attracts electrons and protons to one another, while planets and celestial objects are attracted to each other by gravity. Because of the discretization of angular momentum postulated in early quantum mechanics by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies.
qas: answers: text: Bohr model
question: What model id used to calculate energy levels of hydrogen?

answers: text: gravity
question: What attracts planets and celestial items?

answers: text: electrons and protons
question: What does the electromagnetic force attract to one another?

context: A more accurate description of the hydrogen atom comes from a purely quantum mechanical treatment that uses the Schrödinger equation, Dirac equation or even the Feynman path integral formulation to calculate the probability density of the electron around the proton. The most complicated treatments allow for the small effects of special relativity and vacuum polarization. In the quantum mechanical treatment, the electron in a ground state hydrogen atom has no angular momentum at all—an illustration of how the "planetary orbit" conception of electron motion differs from reality.
qas: answers: text: angular
question: What kind of movement does the electron not have in ground state?

context: There exist two different spin isomers of hydrogen diatomic molecules that differ by the relative spin of their nuclei. In the orthohydrogen form, the spins of the two protons are parallel and form a triplet state with a molecular spin quantum number of 1 (1⁄2+1⁄2); in the parahydrogen form the spins are antiparallel and form a singlet with a molecular spin quantum number of 0 (1⁄2–1⁄2). At standard temperature and pressure, hydrogen gas contains about 25% of the para form and 75% of the ortho form, also known as the "normal form". The equilibrium ratio of orthohydrogen to parahydrogen depends on temperature, but because the ortho form is an excited state and has a higher energy than the para form, it is unstable and cannot be purified. At very low temperatures, the equilibrium state is composed almost exclusively of the para form. The liquid and gas phase thermal properties of pure parahydrogen differ significantly from those of the normal form because of differences in rotational heat capacities, as discussed more fully in spin isomers of hydrogen. The ortho/para distinction also occurs in other hydrogen-containing molecules or functional groups, such as water and methylene, but is of little significance for their thermal properties.
qas: answers: text: 2
question: How many different spin isomers exist?

answers: text: triplet state
question: What state are the protons in when in the orthohydrogen form?

answers: text: normal
question: When hydrogen gas is in standard temperature and pressure, what form is it considered in>

answers: text: 25%
question: What percent of para form does hydrogen gas contain?

answers: text: 75%
question: What percent of ortho form does hydrogen gas contain?

context: The uncatalyzed interconversion between para and ortho H2 increases with increasing temperature; thus rapidly condensed H2 contains large quantities of the high-energy ortho form that converts to the para form very slowly. The ortho/para ratio in condensed H2 is an important consideration in the preparation and storage of liquid hydrogen: the conversion from ortho to para is exothermic and produces enough heat to evaporate some of the hydrogen liquid, leading to loss of liquefied material. Catalysts for the ortho-para interconversion, such as ferric oxide, activated carbon, platinized asbestos, rare earth metals, uranium compounds, chromic oxide, or some nickel compounds, are used during hydrogen cooling.
qas: answers: text: ferric oxide, activated carbon, platinized asbestos, rare earth metals, uranium compounds, chromic oxide, or some nickel compounds
question: What are some catalysts used in hydrogen cooling

context: While H2 is not very reactive under standard conditions, it does form compounds with most elements. Hydrogen can form compounds with elements that are more electronegative, such as halogens (e.g., F, Cl, Br, I), or oxygen; in these compounds hydrogen takes on a partial positive charge. When bonded to fluorine, oxygen, or nitrogen, hydrogen can participate in a form of medium-strength noncovalent bonding with other similar molecules between their hydrogens called hydrogen bonding, which is critical to the stability of many biological molecules. Hydrogen also forms compounds with less electronegative elements, such as the metals and metalloids, in which it takes on a partial negative charge. These compounds are often known as hydrides.
qas: answers: text: positive charge
question: What ind of charge does hydrogen take when mixed with electronegative particles?

answers: text: negative
question: What type of charge does hydrogen take when combined with a metal?

answers: text: hydrides
question: When hydrogen forms with a metal, what is the compound called?

answers: text: not
question: Is H2 reactive in standard conditions?

context: Hydrogen forms a vast array of compounds with carbon called the hydrocarbons, and an even vaster array with heteroatoms that, because of their general association with living things, are called organic compounds. The study of their properties is known as organic chemistry and their study in the context of living organisms is known as biochemistry. By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it is the carbon-hydrogen bond which gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. Millions of hydrocarbons are known, and they are usually formed by complicated synthetic pathways, which seldom involve elementary hydrogen.
qas: answers: text: hydrocarbons
question: What is the form of hydrogen and carbon called?

answers: text: organic compounds
question: What is the form of hydrogen and heteroatoms called?

answers: text: organic chemistry
question: What is the study of organic compounds properties known as?

answers: text: biochemistry
question: What is the study of living organisms known as?

answers: text: carbon
question: Organic compounds are only required to conatin what?

context: Compounds of hydrogen are often called hydrides, a term that is used fairly loosely. The term "hydride" suggests that the H atom has acquired a negative or anionic character, denoted H−, and is used when hydrogen forms a compound with a more electropositive element. The existence of the hydride anion, suggested by Gilbert N. Lewis in 1916 for group I and II salt-like hydrides, was demonstrated by Moers in 1920 by the electrolysis of molten lithium hydride (LiH), producing a stoichiometry quantity of hydrogen at the anode. For hydrides other than group I and II metals, the term is quite misleading, considering the low electronegativity of hydrogen. An exception in group II hydrides is BeH
2, which is polymeric. In lithium aluminium hydride, the AlH−
4 anion carries hydridic centers firmly attached to the Al(III).
qas: answers: text: Gilbert N. Lewis
question:  Who suggested that hydride anions existed?character does the H atom have in a hydride?

answers: text: group II
question: What group of hydrides is BEH considered polymeric?

context: Although hydrides can be formed with almost all main-group elements, the number and combination of possible compounds varies widely; for example, there are over 100 binary borane hydrides known, but only one binary aluminium hydride. Binary indium hydride has not yet been identified, although larger complexes exist.
qas: answers: text: over 100
question: How many binary borane hydrides are known?

answers: text: 1
question: How many binary aluminum hydrides are there?

context: In inorganic chemistry, hydrides can also serve as bridging ligands that link two metal centers in a coordination complex. This function is particularly common in group 13 elements, especially in boranes (boron hydrides) and aluminium complexes, as well as in clustered carboranes.
qas: answers: text: inorganic chemistry
question: What chemistry do hydrides serve as bridging ligands?

answers: text: link two metal centers
question: What do hydrides that are bridging ligands link up?

answers: text: group 13
question: What group is briging ligands most common in?

context: Oxidation of hydrogen removes its electron and gives H+, which contains no electrons and a nucleus which is usually composed of one proton. That is why H+ is often called a proton. This species is central to discussion of acids. Under the Bronsted-Lowry theory, acids are proton donors, while bases are proton acceptors.
qas: answers: text: electrons
question: When hydrogen oxidates, what is it removing?

answers: text: H+
question: When hydrogen oxidates, what does it end up giving?

answers: text: Bronsted-Lowry
question: What theory suggests that acids are proton donors?

context: A bare proton, H+, cannot exist in solution or in ionic crystals, because of its unstoppable attraction to other atoms or molecules with electrons. Except at the high temperatures associated with plasmas, such protons cannot be removed from the electron clouds of atoms and molecules, and will remain attached to them. However, the term 'proton' is sometimes used loosely and metaphorically to refer to positively charged or cationic hydrogen attached to other species in this fashion, and as such is denoted "H+" without any implication that any single protons exist freely as a species.
qas: answers: text: H+
question: What is another term for a bare proton?

context: To avoid the implication of the naked "solvated proton" in solution, acidic aqueous solutions are sometimes considered to contain a less unlikely fictitious species, termed the "hydronium ion" (H
3O+). However, even in this case, such solvated hydrogen cations are more realistically conceived as being organized into clusters that form species closer to H
9O+
4. Other oxonium ions are found when water is in acidic solution with other solvents.
qas: answers: text: in acidic solution with other solvents
question: Where can oxonium ions be found?

answers: text: hydronium ion
question: What other term is a solvated protons referred as?

context: Although exotic on Earth, one of the most common ions in the universe is the H+
3 ion, known as protonated molecular hydrogen or the trihydrogen cation.
qas: answers: text: protonated
question: What kind of molecular hydrogen is the H+3 knows as?

answers: text: trihydrogen cation
question: What kind of cation is the H+3 knowns as?

context: Hydrogen has three naturally occurring isotopes, denoted 1H, 2H and 3H. Other, highly unstable nuclei (4H to 7H) have been synthesized in the laboratory but not observed in nature.
qas: answers: text: 3H
question: How many natural isotopes does hydrogen have>

answers: text: denoted 1H, 2H and 3H
question: What are the names of these isotopes?

answers: text: 4H to 7H
question: Which isotopes have unstable nuclei?

context: Hydrogen is the only element that has different names for its isotopes in common use today. During the early study of radioactivity, various heavy radioactive isotopes were given their own names, but such names are no longer used, except for deuterium and tritium. The symbols D and T (instead of 2H and 3H) are sometimes used for deuterium and tritium, but the corresponding symbol for protium, P, is already in use for phosphorus and thus is not available for protium. In its nomenclatural guidelines, the International Union of Pure and Applied Chemistry allows any of D, T, 2H, and 3H to be used, although 2H and 3H are preferred.
qas: answers: text: Hydrogen
question: Which element is the only that has different names for its isotopes?

answers: text: deuterium and tritium
question: What are the only two names still used for radioactive isotopes?

answers: text: D and T
question: What are the symbols used for deuterium and tritium?

answers: text: phosphorus
question: What does the symbol P represent?

answers: text: 2H and 3H
question: What are the preferred symbols for deuterium and tritium?

context: In 1671, Robert Boyle discovered and described the reaction between iron filings and dilute acids, which results in the production of hydrogen gas. In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "flammable air". He speculated that "flammable air" was in fact identical to the hypothetical substance called "phlogiston" and further finding in 1781 that the gas produces water when burned. He is usually given credit for its discovery as an element. In 1783, Antoine Lavoisier gave the element the name hydrogen (from the Greek ὑδρο- hydro meaning "water" and -γενής genes meaning "creator") when he and Laplace reproduced Cavendish's finding that water is produced when hydrogen is burned.
qas: answers: text: 1671
question: What year was the discovery of hydrogen gas?

answers: text: Robert Boyle
question: Who discovered Hydrogen gas?

answers: text: Henry Cavendish
question: Who recognized hydrogen gas as a discreet substance?

answers: text: 1766
question: In what year did Henry Cavendish recognize hydrogen gas as a discreet substance?

answers: text: water
question: What does gas produce when burned?

context: Lavoisier produced hydrogen for his experiments on mass conservation by reacting a flux of steam with metallic iron through an incandescent iron tube heated in a fire. Anaerobic oxidation of iron by the protons of water at high temperature can be schematically represented by the set of following reactions:
qas: answers: text: reacting a flux of steam with metallic iron through an incandescent iron tube heated in a fire
question: How did Lavoisier produce hydrogen for his experiments?

context: Hydrogen was liquefied for the first time by James Dewar in 1898 by using regenerative cooling and his invention, the vacuum flask. He produced solid hydrogen the next year. Deuterium was discovered in December 1931 by Harold Urey, and tritium was prepared in 1934 by Ernest Rutherford, Mark Oliphant, and Paul Harteck. Heavy water, which consists of deuterium in the place of regular hydrogen, was discovered by Urey's group in 1932. François Isaac de Rivaz built the first de Rivaz engine, an internal combustion engine powered by a mixture of hydrogen and oxygen in 1806. Edward Daniel Clarke invented the hydrogen gas blowpipe in 1819. The Döbereiner's lamp and limelight were invented in 1823.
qas: answers: text: James Dewar
question: Who was the first to liquidize hydrogen?

answers: text: 1898
question: In what year Did James Dewar first liquidize hydrogen?

answers: text: 1931
question: What year was Deuterium discovered?

answers: text: Harold Urey
question: Who was the first to discover deuterium?

answers: text: 1934
question: What year was tritium discovered?

context: The first hydrogen-filled balloon was invented by Jacques Charles in 1783. Hydrogen provided the lift for the first reliable form of air-travel following the 1852 invention of the first hydrogen-lifted airship by Henri Giffard. German count Ferdinand von Zeppelin promoted the idea of rigid airships lifted by hydrogen that later were called Zeppelins; the first of which had its maiden flight in 1900. Regularly scheduled flights started in 1910 and by the outbreak of World War I in August 1914, they had carried 35,000 passengers without a serious incident. Hydrogen-lifted airships were used as observation platforms and bombers during the war.
qas: answers: text: Jacques Charles
question: Who invented the hydrogen filled balloons?

answers: text: 1783
question: What year was hydrogen filled balloons invented?

answers: text: Zeppelins
question: what were the hydrogen lifted airships called?

answers: text: 1900
question: In what year did the first zeppelin make flight?

context: The first non-stop transatlantic crossing was made by the British airship R34 in 1919. Regular passenger service resumed in the 1920s and the discovery of helium reserves in the United States promised increased safety, but the U.S. government refused to sell the gas for this purpose. Therefore, H2 was used in the Hindenburg airship, which was destroyed in a midair fire over New Jersey on 6 May 1937. The incident was broadcast live on radio and filmed. Ignition of leaking hydrogen is widely assumed to be the cause, but later investigations pointed to the ignition of the aluminized fabric coating by static electricity. But the damage to hydrogen's reputation as a lifting gas was already done.
qas: answers: text: the British
question: Who made the first non stop transatlantic crossing?

answers: text: 1919
question: What year was this done?

answers: text: 1937
question: What year did the airship get destroyed?

answers: text: New Jersey
question: What city was the ship over when it caught fire?

context: In the same year the first hydrogen-cooled turbogenerator went into service with gaseous hydrogen as a coolant in the rotor and the stator in 1937 at Dayton, Ohio, by the Dayton Power & Light Co.; because of the thermal conductivity of hydrogen gas, this is the most common type in its field today.
qas: answers: text: 1937
question: In what year did the first hydrogen cooled turbogenerator go into service?

answers: text: Ohio
question: What state is the Dayton Power and light Company located?

context: The nickel hydrogen battery was used for the first time in 1977 aboard the U.S. Navy's Navigation technology satellite-2 (NTS-2). For example, the ISS, Mars Odyssey and the Mars Global Surveyor are equipped with nickel-hydrogen batteries. In the dark part of its orbit, the Hubble Space Telescope is also powered by nickel-hydrogen batteries, which were finally replaced in May 2009, more than 19 years after launch, and 13 years over their design life.
qas: answers: text: 1977
question: What year was the first nickel hydrogen battery used?

answers: text: 2009
question: In what year did the hubble space telescope finally get the nickel hydrogen battery?

context: Because of its simple atomic structure, consisting only of a proton and an electron, the hydrogen atom, together with the spectrum of light produced from it or absorbed by it, has been central to the development of the theory of atomic structure. Furthermore, the corresponding simplicity of the hydrogen molecule and the corresponding cation H+
2 allowed fuller understanding of the nature of the chemical bond, which followed shortly after the quantum mechanical treatment of the hydrogen atom had been developed in the mid-1920s.
qas: answers: text: a proton and an electron
question: What is the hydrogen atom made up of?

answers: text: atomic structure
question: What theory is the hydrogen atom a big part of?

answers: text: 1920s
question: When was the quantum mechanical treatment of the hydrogen atom developed?

context: One of the first quantum effects to be explicitly noticed (but not understood at the time) was a Maxwell observation involving hydrogen, half a century before full quantum mechanical theory arrived. Maxwell observed that the specific heat capacity of H2 unaccountably departs from that of a diatomic gas below room temperature and begins to increasingly resemble that of a monatomic gas at cryogenic temperatures. According to quantum theory, this behavior arises from the spacing of the (quantized) rotational energy levels, which are particularly wide-spaced in H2 because of its low mass. These widely spaced levels inhibit equal partition of heat energy into rotational motion in hydrogen at low temperatures. Diatomic gases composed of heavier atoms do not have such widely spaced levels and do not exhibit the same effect.
qas: answers: text: Maxwell
question: Who observed the specific heat capacity of H2?

answers: text: spacing of the (quantized) rotational energy levels
question: What cause H2 to resemble monatomic gas?

answers: text: quantum theory
question: What theory supports this?

context: Hydrogen, as atomic H, is the most abundant chemical element in the universe, making up 75% of normal matter by mass and over 90% by number of atoms (most of the mass of the universe, however, is not in the form of chemical-element type matter, but rather is postulated to occur as yet-undetected forms of mass such as dark matter and dark energy). This element is found in great abundance in stars and gas giant planets. Molecular clouds of H2 are associated with star formation. Hydrogen plays a vital role in powering stars through the proton-proton reaction and the CNO cycle nuclear fusion.
qas: answers: text: 75%
question: What percent of normal matter is hydrogen?

answers: text: 90%
question: What percent of atoms is hydrogen?

answers: text: dark matter and dark energy
question: What 2 forms of mass is most of the universe consisted of?

answers: text: stars
question: Clouds of H2 form what?

context: Throughout the universe, hydrogen is mostly found in the atomic and plasma states 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 and high emissivity (producing the light from the Sun and other stars). 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. Hydrogen is found in the neutral atomic state in the interstellar medium. The large amount of neutral hydrogen found in the damped Lyman-alpha systems is thought to dominate the cosmological baryonic density of the Universe up to redshift z=4.
qas: answers: text: atomic and plasma
question: In what states is hydrogen mostly found in the universe?

answers: text: plasma
question: Hydrogens electron and proton are not bound together in what state?

answers: text: neutral atomic state
question: in the interstellar medium, what state is hydrogen in?

answers: text: cosmological baryonic density of the Universe
question: The neutral hydrogen found in the damped Lyman-alpha systems dominates what?

context: Under ordinary conditions on Earth, elemental hydrogen exists as the diatomic gas, H2. However, hydrogen gas is very rare in the Earth's atmosphere (1 ppm by volume) because of its light weight, which enables it to escape from Earth's gravity more easily than heavier gases. However, hydrogen is the third most abundant element on the Earth's surface, mostly in the form of chemical compounds such as hydrocarbons and water. Hydrogen gas is produced by some bacteria and algae and is a natural component of flatus, as is methane, itself a hydrogen source of increasing importance.
qas: answers: text: third most abundant
question: How abundant is hydrogen on the earths surface?

answers: text: bacteria and algae
question: what produces hydrogen gas?

context: A molecular form called protonated molecular hydrogen (H+
3) is found in the interstellar medium, where it is generated by ionization of molecular hydrogen from cosmic rays. This charged ion has also been observed in the upper atmosphere of the planet Jupiter. The ion is relatively stable in the environment of outer space due to the low temperature and density. H+
3 is one of the most abundant ions in the Universe, and it plays a notable role in the chemistry of the interstellar medium. Neutral triatomic hydrogen H3 can only exist in an excited form and is unstable. By contrast, the positive hydrogen molecular ion (H+
2) is a rare molecule in the universe.
qas: answers: text: protonated molecular hydrogen
question: What molecular form is found in the interstellar medium?

answers: text: ionization of molecular hydrogen from cosmic rays
question: What generates protonated molecular hydrogen?

answers: text: Jupiter
question: On what planet can you find  protonated molecular hydrogen?

answers: text: excited form
question: In what way can Neutral triatomic hydrogen exist?

context: H
2 is produced in chemistry and biology laboratories, often as a by-product of other reactions; in industry for the hydrogenation of unsaturated substrates; and in nature as a means of expelling reducing equivalents in biochemical reactions.
qas: answers: text: expelling reducing equivalents in biochemical reactions
question: How does nature produce H2?

answers: text: by-product of other reactions
question: How do labs produce H2?

context: The electrolysis of water is a simple method of producing hydrogen. A low voltage current is run through the water, and gaseous oxygen forms at the anode while gaseous hydrogen forms at the cathode. Typically the cathode is made from platinum or another inert metal when producing hydrogen for storage. If, however, the gas is to be burnt on site, oxygen is desirable to assist the combustion, and so both electrodes would be made from inert metals. (Iron, for instance, would oxidize, and thus decrease the amount of oxygen given off.) The theoretical maximum efficiency (electricity used vs. energetic value of hydrogen produced) is in the range 80–94%.
qas: answers: text: electrolysis of water
question: What is an easy way to produce hydrogen?

answers: text: anode
question: Where does the gaseous oxygen form at?

answers: text: cathode
question: Where does the gaseous hydrogen form at?

context: An alloy of aluminium and gallium in pellet form added to water can be used to generate hydrogen. The process also produces alumina, but the expensive gallium, which prevents the formation of an oxide skin on the pellets, can be re-used. This has important potential implications for a hydrogen economy, as hydrogen can be produced on-site and does not need to be transported.
qas: answers: text: hydrogen
question: When you combine an alloy of alluminum and gallium to water, what do you get?

answers: text: alumina
question: What else can it produce?

answers: text: the expensive gallium
question: What can be reused after the formation?

context: Hydrogen can be prepared in several different ways, but economically the 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 (1000–1400 K, 700–1100 °C or 1300–2000 °F), steam (water vapor) reacts with methane to yield carbon monoxide and H
2.
qas: answers: text: hydrocarbons
question: The most economical way to prepare hydrogen involves removing it from what?

answers: text: 1000–1400 K, 700–1100 °C or 1300–2000 °F
question: What temperature is needed for steam to react with methane?

context: This reaction is favored at low pressures but is nonetheless conducted at high pressures (2.0  MPa, 20 atm or 600 inHg). This is because high-pressure H
2 is the most marketable product and Pressure Swing Adsorption (PSA) purification systems work better at higher pressures. The product mixture is known as "synthesis gas" because it is often used directly for the production of methanol and related compounds. Hydrocarbons other than methane can be used to produce synthesis gas with varying product ratios. One of the many complications to this highly optimized technology is the formation of coke or carbon:
qas: answers: text: high pressures
question: At what pressure does PSA work best in?

answers: text: production of methanol
question: What is synthesis gas used for?

answers: text: Hydrocarbons
question: Besides methane, what else can be used to produce synthesis gas?

context: Consequently, steam reforming typically employs an excess of H
2O. Additional hydrogen can be recovered from the steam by use of carbon monoxide through the water gas shift reaction, especially with an iron oxide catalyst. This reaction is also a common industrial source of carbon dioxide:
qas: answers: text: use of carbon monoxide through the water gas shift reaction
question: How can it be recovered through steam?

context: Hydrogen is sometimes produced and consumed in the same industrial process, without being separated. In the Haber process for the production of ammonia, hydrogen is generated from natural gas. Electrolysis of brine to yield chlorine also produces hydrogen as a co-product.
qas: answers: text: ammonia
question: When hydrogen is generated from natural gas, what des it produce?

answers: text: Electrolysis of brine to yield chlorine
question: How is hydrogen produced as a co product?

context: There are more than 200 thermochemical cycles which can be used for water splitting, around a dozen of these cycles such as the iron oxide cycle, cerium(IV) oxide–cerium(III) oxide cycle, zinc zinc-oxide cycle, sulfur-iodine cycle, copper-chlorine cycle and hybrid sulfur cycle are under research and in testing phase to produce hydrogen and oxygen from water and heat without using electricity. A number of laboratories (including in France, Germany, Greece, Japan, and the USA) are developing thermochemical methods to produce hydrogen from solar energy and water.
qas: answers: text: produce hydrogen and oxygen from water and heat without using electricity
question: What are the thermochemical cycyles in a testing phase for?

answers: text: solar energy and water
question: What are labs trying to produce hydrogen from?

answers: text: France, Germany, Greece, Japan, and the USA
question: What countries are testing this?

context: Under anaerobic conditions, iron and steel alloys are slowly oxidized by the protons of water concomitantly reduced in molecular hydrogen (H
2). The anaerobic corrosion of iron leads first to the formation of ferrous hydroxide (green rust) and can be described by the following reaction:
qas: answers: text: anaerobic
question: What condition is iron and steel alloys slowly oxidized?

answers: text: formation of ferrous hydroxide
question: What does the anaerobic corrosion of iron lead to?

answers: text: green rust
question: What is another name for formation of ferrous hydroxide?

context: In its turn, under anaerobic conditions, the ferrous hydroxide (Fe(OH)
2 ) can be oxidized by the protons of water to form magnetite and molecular hydrogen. This process is described by the Schikorr reaction:
qas: answers: text: anaerobic
question: Under what condition can ferrous hydroxide be oxidized?

answers: text: magnetite and molecular hydrogen
question: What does this process form?

answers: text: Schikorr reaction
question: What reaction describes this process?

context: In the absence of atmospheric oxygen (O
2), in deep geological conditions prevailing far away from Earth atmosphere, hydrogen (H
2) is produced during the process of serpentinization by the anaerobic oxidation by the water protons (H+) of the ferrous (Fe2+) silicate present in the crystal lattice of the fayalite (Fe
2SiO
4, the olivine iron-endmember). The corresponding reaction leading to the formation of magnetite (Fe
3O
4), quartz (SiO
2) and hydrogen (H
2) is the following:
qas: answers: text: serpentinization by the anaerobic oxidation
question: How is hydrogen produced when there is no atmospheric oxygen?

answers: text: crystal lattice of the fayalite
question: Where do you find silicate?

context: From all the fault gases formed in power transformers, hydrogen is the most common and is generated under most fault conditions; thus, formation of hydrogen is an early indication of serious problems in the transformer's life cycle.
qas: answers: text: hydrogen
question: What is the most common gas found in power tranformers?

context: Large quantities of H
2 are needed in the petroleum and chemical industries. The largest application of H
2 is for the processing ("upgrading") of fossil fuels, and in the production of ammonia. The key consumers of H
2 in the petrochemical plant include hydrodealkylation, hydrodesulfurization, and hydrocracking. H
2 has several other important uses. H
2 is used as a hydrogenating agent, particularly in increasing the level of saturation of unsaturated fats and oils (found in items such as margarine), and in the production of methanol. It is similarly the source of hydrogen in the manufacture of hydrochloric acid. H
2 is also used as a reducing agent of metallic ores.
qas: answers: text: petroleum and chemical industries
question: Where are large quantities of H2 needed?

answers: text: hydrodealkylation, hydrodesulfurization, and hydrocracking
question: What are the consumers of H2 in petrochemical plant?

context: Hydrogen is highly soluble in many rare earth and transition metals and is soluble in both nanocrystalline and amorphous metals. Hydrogen solubility in metals is influenced by local distortions or impurities in the crystal lattice. These properties may be useful when hydrogen is purified by passage through hot palladium disks, but the gas's high solubility is a metallurgical problem, contributing to the embrittlement of many metals, complicating the design of pipelines and storage tanks.
qas: answers: text: rare earth and transition metals
question: Where is hydrogen highly soluble?

answers: text: nanocrystalline and amorphous metals
question: Where can you find soluble hydrogen?

answers: text: local distortions or impurities in the crystal lattice
question: What influences hydrogens solubility in metals?

answers: text: when hydrogen is purified by passage through hot palladium disks
question: When are these useful?

answers: text: gas's high solubility is a metallurgical problem, contributing to the embrittlement of many metals, complicating the design of pipelines and storage tanks
question: When is it damaging?

context: Apart from its use as a reactant, H
2 has wide applications in physics and engineering. It is used as a shielding gas in welding methods such as atomic hydrogen welding. 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. Because H
2 is lighter than air, having a little more than 1⁄14 of the density of air, it was once widely used as a lifting gas in balloons and airships.
qas: answers: text: in physics and engineering
question: Where else is H2 applied?

answers: text: as the rotor coolant
question: How is H2 used in electrical generators at power stations?

answers: text: it has the highest thermal conductivity of any gas
question: Why is it used as the rotor coolant?

answers: text: cryogenic
question: What research uses liquid H2?

context: In more recent applications, hydrogen is used pure or mixed with nitrogen (sometimes called forming gas) as a tracer gas for minute leak detection. Applications can be found in the automotive, chemical, power generation, aerospace, and telecommunications industries. Hydrogen is an authorized food additive (E 949) that allows food package leak testing among other anti-oxidizing properties.
qas: answers: text: as a tracer gas for minute leak detection
question: Why would one use hydrogen mixed with nitrogen?

answers: text: automotive, chemical, power generation, aerospace, and telecommunications
question: What industries can you find these applications?

answers: text: allows food package leak testing
question: How is hydrogen used as a food additive?

context: Hydrogen's rarer isotopes also each have specific applications. Deuterium (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.
qas: answers: text: Deuterium
question: What isotope is used in nuclear fission?

answers: text: nuclear reactors
question: Where is tritium produced?

answers: text: production of hydrogen bombs, as an isotopic label in the biosciences, and as a radiation source in luminous paints
question: What is tritium used for?

context: Hydrogen is commonly used in power stations as a coolant in generators due to a number of favorable properties that are a direct result of its light diatomic molecules. These include low density, low viscosity, and the highest specific heat and thermal conductivity of all gases.
qas: answers: text: as a coolant in generators
question: How is hydrogen used at power stations?

answers: text: favorable properties that are a direct result of its light diatomic molecules
question: Why is it used as a coolant?

answers: text: low density, low viscosity, and the highest specific heat and thermal conductivity of all gases
question: What are these properties?

context: Hydrogen is not an energy resource, except in the hypothetical context of commercial nuclear fusion power plants using deuterium or tritium, a technology presently far from development. The Sun's energy comes from nuclear fusion of hydrogen, but this process is difficult to achieve controllably on Earth. Elemental hydrogen from solar, biological, or electrical sources require more energy to make it than is obtained by burning it, so in these cases hydrogen functions as an energy carrier, like a battery. Hydrogen may be obtained from fossil sources (such as methane), but these sources are unsustainable.
qas: answers: text: not
question: Is Hydrogen considered an energy resource?

answers: text: nuclear fusion of hydrogen
question: Where does the sun get its energy from?

answers: text: energy carrier
question: How does hydrogen function when it s burned?

context: The energy density per unit volume of both liquid hydrogen and compressed hydrogen gas at any practicable pressure is significantly less than that of traditional fuel sources, although the energy density per unit fuel mass is higher. Nevertheless, elemental hydrogen has been widely discussed in the context of energy, as a possible future carrier of energy on an economy-wide scale. For example, CO
2 sequestration followed by carbon capture and storage could be conducted at the point of H
2 production from fossil fuels. Hydrogen used in transportation would burn relatively cleanly, with some NOx emissions, but without carbon emissions. However, the infrastructure costs associated with full conversion to a hydrogen economy would be substantial. Fuel cells can convert hydrogen and oxygen directly to electricity more efficiently than internal combustion engines.
qas: answers: text: elemental
question: What form of hydrogen has been discussed as a ussage for fuel?

context: Hydrogen is employed to saturate broken ("dangling") bonds of amorphous silicon and amorphous carbon that helps stabilizing material properties. It is also a potential electron donor in various oxide materials, including ZnO, SnO2, CdO, MgO, ZrO2, HfO2, La2O3, Y2O3, TiO2, SrTiO3, LaAlO3, SiO2, Al2O3, ZrSiO4, HfSiO4, and SrZrO3.
qas: answers: text: to saturate broken ("dangling") bonds of amorphous silicon and amorphous carbon that helps stabilizing material properties
question: Why is hydrogen employed?

answers: text: a potential electron donor
question: How is hydrogen used in oxide materials?

answers: text: ZnO, SnO2, CdO, MgO, ZrO2, HfO2, La2O3, Y2O3, TiO2, SrTiO3, LaAlO3, SiO2, Al2O3, ZrSiO4, HfSiO4, and SrZrO3
question: What oxide materials use hydrogen as an electron donor?

context: H2 is a product of some types of anaerobic metabolism and is produced by several microorganisms, usually via reactions catalyzed by iron- or nickel-containing enzymes called hydrogenases. These enzymes catalyze the reversible redox reaction between H2 and its component two protons and two electrons. Creation of hydrogen gas occurs in the transfer of reducing equivalents produced during pyruvate fermentation to water. The natural cycle of hydrogen production and consumption by organisms is called the hydrogen cycle.
qas: answers: text: hydrogenases
question: What enzymes are used to produce H2?

answers: text: in the transfer of reducing equivalents produced during pyruvate fermentation to water
question: When does hydrogen gas occur?

answers: text: hydrogen cycle
question: What is the natural cycle of hydrogen production and consumption by organisms called?

context: Water splitting, in which water is decomposed into its component protons, electrons, and oxygen, occurs in the light reactions in all photosynthetic organisms. Some such organisms, including the alga Chlamydomonas reinhardtii and cyanobacteria, have evolved a second step in the dark reactions in which protons and electrons are reduced to form H2 gas by specialized hydrogenases in the chloroplast. Efforts have been undertaken to genetically modify cyanobacterial hydrogenases to efficiently synthesize H2 gas even in the presence of oxygen. Efforts have also been undertaken with genetically modified alga in a bioreactor.
qas: answers: text: Water splitting
question: What is the decomposition of water into its components called?

answers: text: in the light reactions in all photosynthetic organisms
question: Where does water splitting occur?

answers: text: alga Chlamydomonas reinhardtii and cyanobacteria
question: What organisms can form H2 gas?

answers: text: by specialized hydrogenases in the chloroplast
question: How are these gases formed?

context: Hydrogen poses a number of hazards to human safety, from potential detonations and fires when mixed with air to being an asphyxiant in its pure, oxygen-free form. In addition, liquid hydrogen is a cryogen and presents dangers (such as frostbite) associated with very cold liquids. Hydrogen dissolves in many metals, and, in addition to leaking out, may have adverse effects on them, such as hydrogen embrittlement, leading to cracks and explosions. Hydrogen gas leaking into external air may spontaneously ignite. Moreover, hydrogen fire, while being extremely hot, is almost invisible, and thus can lead to accidental burns.
qas: answers: text: potential detonations and fires when mixed with air to being an asphyxiant in its pure, oxygen-free form
question: What threats can hydrogen cause to human saftey?

answers: text: cracks and explosions
question: What can hydrogen embrittlement lead to?

context: Even interpreting the hydrogen data (including safety data) is confounded by a number of phenomena. Many physical and chemical properties of hydrogen depend on the parahydrogen/orthohydrogen ratio (it often takes days or weeks at a given temperature to reach the equilibrium ratio, for which the data is usually given). Hydrogen detonation parameters, such as critical detonation pressure and temperature, strongly depend on the container geometry.
qas: answers: text: the parahydrogen/orthohydrogen ratio
question: What do physical and chemical properties of hydrogen depend on?

answers: text: days or weeks
question: How long can it take to reach the equilibrium ratio?

answers: text: container geometry
question: What do Hydrogen detonation parameters depend on?