#Molar mass of h2 skin
#Molar mass of h2 full

It spontaneously reacts with chlorine and fluorine to form hydrogen chloride and hydrogen fluoride, respectively. The kinetic basis of the low reactivity is the nonpolar nature of H 2 and its weak polarizability. The thermodynamic basis of this low reactivity is the very strong H-H bond, with a bond dissociation energy of 435.7 kJ/mol. H 2 is unreactive compared to diatomic elements such as halogens or oxygen.

#Molar mass of h2 skin

The visible flames in the photographs were the result of carbon compounds in the airship skin burning. The destruction of the Hindenburg airship was a notorious example of hydrogen combustion and the cause is still debated. Hydrogen flames in other conditions are blue, resembling blue natural gas flames. The detection of a burning hydrogen leak may require a flame detector such leaks can be very dangerous. 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, which uses an ammonium perchlorate composite. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 ☌ (932 ☏). The explosive reactions may be triggered by spark, heat, or sunlight. Hydrogen gas forms explosive mixtures with air in concentrations from 4–74% and with chlorine at 5–95%. The enthalpy of combustion is −286 kJ/mol. Hydrogen gas ( dihydrogen or molecular hydrogen) is highly flammable:Ģ H 2(g) + O 2(g) → 2 H 2O(l) + 572 kJ/2 mol = 286 kJ/mol = 141.865 MJ/kg)

#Molar mass of h2 full

The Space Shuttle Main Engine burnt hydrogen with oxygen, producing a nearly invisible flame at full thrust. Hydrogen is problematic in metallurgy because it can embrittle many metals, complicating the design of pipelines and storage tanks. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production, mostly for the fertilizer market. A small percentage is also produced using more energy-intensive methods such as the electrolysis of water. Industrial production is mainly from steam reforming of natural gas, oil reforming, or coal gasification. In 1766–1781, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, the property for which it was later named: in Greek, hydrogen means 'water-former'. Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. Because hydrogen is the only neutral atom for which the Schrödinger equation can be solved analytically, the study of its energetics and chemical bonding has played a key role in the development of quantum mechanics. The H + cation is simply a proton (symbol p) but its behavior in aqueous solutions and in ionic compounds involves screening of its electric charge by nearby polar molecules or anions. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) where it is known as a hydride, or as a positively charged (i.e., cation) species denoted by the symbol H +. Hydrogen plays a particularly important role in acid–base reactions because these reactions usually involve the exchange of protons between soluble molecules. Hydrogen is nonmetallic, except at extremely high pressures, and readily forms a single covalent bond with most nonmetallic elements, forming compounds such as water and nearly all organic compounds.

The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 years later during the recombination epoch, when the plasma had cooled enough for electrons to remain bound to protons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang.

For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter. It is colorless, odorless, tasteless, non-toxic, and highly combustible. At standard conditions hydrogen is a gas of diatomic molecules having the formula H 2. Hydrogen is the chemical element with the symbol H and atomic number 1.