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  • atom
  • 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 . (wikipedia.org)
  • 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 91 nm wavelength. (wikipedia.org)
  • 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 atomic electron and proton are held together by electromagnetic force, while planets and celestial objects are held by gravity. (wikipedia.org)
  • 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. (wikipedia.org)
  • helium
  • After hydrogen, helium is the second lightest and second most abundant element in the observable universe, being present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. (wikipedia.org)
  • Large amounts of new helium are being created by nuclear fusion of hydrogen in stars. (wikipedia.org)
  • bonds
  • Water molecules form hydrogen bonds with each other and are strongly polar. (wikipedia.org)
  • The molecules of water are constantly moving in relation to each other, and the hydrogen bonds are continually breaking and reforming at timescales faster than 200 femtoseconds (2×10−13 seconds). (wikipedia.org)
  • The relative instability of the carbon-oxygen bonds in the molecule is revealed by the comparison in the table of the energy required to break two C-O bonds in the ethylene oxide or one C-O bond in ethanol and dimethyl ether: This instability correlates with its high reactivity, explaining the ease of its ring-opening reactions (see Chemical properties). (wikipedia.org)
  • ammonium
  • As salts or esters of hydrogen cyanide (HCN, or hydrocyanic acid), cyanides are formed by replacing the hydrogen of hydrogen cyanide with a metal, such as sodium or potassium , or by replacing the hydrogen with a radical (such as ammonium). (newworldencyclopedia.org)
  • 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, which uses an ammonium perchlorate composite. (wikipedia.org)
  • ethanol
  • What we call 'alcohol' actually has the proper chemical name ethanol and belongs to a group of organic molecules called alcohols? (docbrown.info)
  • What we call alcohol in everyday life is a substance whose chemical name is ethanol . (docbrown.info)
  • Ethanol is just one member of a family of substances, the homologous series we call alcohols , which all have the C OH 'hydroxy' functional group in their structure. (docbrown.info)
  • The carbon dioxide is allowed to escape and air is prevented from entering the reaction vessel to stop oxygen oxidising ethanol to ethanoic acid ('acetic acid' or vinegar! (docbrown.info)
  • It is soluble in water, ethanol, propanol, ether, benzene and chloroform and many other kinds of organic substance and is called as the "universal solvent. (chemicalbook.com)
  • IUPAC
  • The accepted IUPAC name of water is oxidane or simply water,or its equivalent in different languages, although there are other systematic names which can be used to describe the molecule. (wikipedia.org)
  • The polarized form of the water molecule, H+ OH− , is also called hydron hydroxide by IUPAC nomenclature. (wikipedia.org)
  • atmosphere
  • One key finding comes from a paper online now in the journal Icarus that shows hydrogen molecules flowing down through Titan's atmosphere and disappearing at the surface. (nasa.gov)
  • The paper describes densities of hydrogen in different parts of the atmosphere and the surface. (nasa.gov)
  • This is about the same rate at which the molecules escape out of the upper atmosphere. (nasa.gov)
  • form
  • Scientists have not yet detected this form of life anywhere, though there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product. (nasa.gov)
  • The new hydrogen findings are consistent with conditions that could produce an exotic, methane-based life form, but do not definitively prove its existence, said Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore, Md., who authored the paper on hydrogen. (nasa.gov)
  • Oxygen unites directly with a number of other elements to form oxides oxide, chemical compound containing oxygen and one other chemical element. (thefreedictionary.com)
  • In plants, cyanides are usually bound to sugar molecules in the form of cyanogenic glycosides and serve the plant as defense against herbivores . (newworldencyclopedia.org)
  • Autothermal reforming (ATR) uses oxygen and carbon dioxide or steam in a reaction with methane to form syngas. (wikipedia.org)
  • Its hydrogen bonding causes its many unique properties, such as having a solid form less dense than its liquid form, a relatively high boiling point of 100 °C for its molar mass, and a high heat capacity. (wikipedia.org)
  • whereby
  • The various cyanides are salts or esters of HCN (hydrogen cyanide or hydrocyanic acid), whereby the hydrogen is replaced with a metal or radical, yielding such as potassium cyanide (KCN), calcium cyanide (CA(CN) 2 ), or ethyl cyanide (CH 3 CH 2 CN). (newworldencyclopedia.org)
  • electron
  • The asymmetrical shape of the molecule arises from a tendency of the four electron pairs in the valence shell of oxygen to arrange themselves symmetrically at the vertices of a tetrahedron around the oxygen nucleus. (thefreedictionary.com)
  • gases
  • An alkali anion exchange membrane (AAEM) is a semipermeable membrane generally made from ionomers and designed to conduct anions while being impermeable to gases such as oxygen or hydrogen. (wikipedia.org)
  • water
  • On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Fahrenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. (nasa.gov)
  • While liquid water is widely regarded as necessary for life, there has been extensive speculation published in the scientific literature that this is not a strict requirement. (nasa.gov)
  • Water is the oxide of hydrogen. (thefreedictionary.com)
  • Because of hydrogen bonding between water molecules, the latent heats latent heat, heat change associated with a change of state or phase (see states of matter). (thefreedictionary.com)
  • Especially due to adhesive (sticky) substances, strongly fluctuating concentrations and a lot of chemicals, the monitoring systems itself must be tailor-made to fight this water analysis challenge. (environmental-expert.com)
  • Because water is a very good solvent, it is rarely pure, and some of the properties of impure water can vary from those of the pure substance. (wikipedia.org)
  • Unlike other analogous hydrides of the oxygen family, water is primarily a liquid under standard conditions due to hydrogen bonding. (wikipedia.org)
  • Water has a very high specific heat capacity of 4.1814 J/(g·K) at 25 °C - the second highest among all the heteroatomic species (after ammonia), as well as a high heat of vaporization (40.65 kJ/mol or 2257 kJ/kg at the normal boiling point), both of which are a result of the extensive hydrogen bonding between its molecules. (wikipedia.org)
  • 20/30/10 standard - 20 mg/l Biochemical Oxygen Demand (BOD), 30 mg/l Suspended Solids (SS), 10 units of E. coli: the water quality standard for greywater use in toilets, laundry and surface irrigation. (wikipedia.org)
  • yield
  • For example, bitter almonds (as opposed to sweet almonds) can yield dangerous amounts of prussic acid (hydrogen cyanide) when eaten raw, but the toxicity can be removed by heating. (newworldencyclopedia.org)
  • biomass
  • This biomass can be converted to convenient energy-containing substances in three different ways: thermal conversion, chemical conversion, and biochemical conversion. (wikipedia.org)
  • ecological
  • adaptive radiation - closely related species that look very different, as a result of having adapted to widely different ecological niches. (wikipedia.org)
  • energy
  • This lack of acetylene is important because that chemical would likely be the best energy source for a methane-based life on Titan, said Chris McKay, an astrobiologist at NASA Ames Research Center, Moffett Field, Calif., who proposed a set of conditions necessary for this kind of methane-based life on Titan in 2005. (nasa.gov)
  • The Titan surface is also so cold that a chemical process that involved a catalyst would be needed to convert hydrogen molecules and acetylene back to methane, even though overall there would be a net release of energy. (nasa.gov)
  • The aboitic substances are circulated in the ecosystem through material cycles and energy cycles. (scribd.com)
  • The uses of wood in furniture, buildings, bridges, and as a source of energy are widely known. (wikipedia.org)