hydrogen


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hydrogen

 (H) [hi´dro-jen]
a chemical element, atomic number 1, atomic weight 1.00797. (See Appendix 6.) It exists as the mass 1 isotope (protium, or light or ordinary hydrogen), mass 2 isotope (deuterium, heavy hydrogen), and mass 3 isotope (tritium).
hydrogen cyanide an extremely poisonous colorless liquid or gas, HCN, a decomposition product of various naturally occurring glycosides and a common cause of cyanide poisoning. Inhalation of the gas can cause death within a minute. Called also hydrocyanic acid.
heavy hydrogen deuterium.
hydrogen ion concentration the degree of concentration of hydrogen ions (the acid element) in a solution. Its symbol is pH, and it expresses the degree to which a solution is acidic or alkaline. The pH range extends from 0 to 14, pH 7 being neutral, a pH of less than 7 indicating acidity, and one above 7 indicating alkalinity. See also acid-base balance.
hydrogen peroxide H2O2, an antiseptic with a mildly antibacterial action. A 3 per cent solution foams on touching skin or mucous membrane and appears to have a mechanical cleansing action.
hydrogen sulfide H2S, a poisonous gas with an offensive smell, released from decaying organic material, natural gas, petroleum, and sulfur deposits, and sometimes used as a chemical reagent.

hy·dro·gen (H),

(hī'drō-jen),
1. A gaseous element, atomic no. 1, atomic wt. 1.00794.
2. The molecular form (H2) of the element. Synonym(s): dihydrogen
[hydro- + G. -gen, producing]

hydrogen

/hy·dro·gen/ (H) (hi´dro-jen) chemical element, at. no. 1; it exists as the mass 1 isotope (protium, light or ordinary h.), mass 2 isotope (deuterium, heavy h.), and mass 3 isotope (tritium) .
hydrogen cyanide  an extremely poisonous liquid or gas, HCN, used as a rodenticide and insecticide.
hydrogen peroxide  a strongly disinfectant cleansing and bleaching liquid, H2O2, used in dilute solution in water.
hydrogen sulfide  an ill-smelling, colorless, poisonous gas, H2S.

hydrogen (H)

[hī′drəjən]
Etymology: Gk, hydor + genein, to produce
a gaseous monovalent element. Its atomic number is 1; its atomic mass is 1.008. It is the simplest and the lightest of the elements and is a colorless, odorless, highly flammable diatomic gas. It occurs in pure form only sparsely in the earth and the atmosphere but is plentiful in the sun and in many other stars. Hydrogen is a component of numerous compounds, many of them produced by the body. As a component of water, hydrogen is crucial in the metabolic interaction of acids, bases, and salts within the body and in the fluid balance necessary for the body to survive.

hy·dro·gen

(H) (hī'drō-jen)
1. A gaseous element, atomic no. 1, atomic wt. 1.00794.
2. The molecular form of the element, H2.
Synonym(s): dihydrogen.
[hydro- + G. -gen, producing]

Hydrogen

The simplest, most common element known in the universe. It is composed of a single electron (negatively charged particle) circling a nucleus consisting of a single proton (positively charged particle). It is the nuclear proton of hydrogen that makes MRI possible by reacting resonantly to radio waves while aligned in a magnetic field.

hy·dro·gen

(hī'drō-jen)
1. Gaseous element, atomic no. 1, atomic wt. 1.00794.
2. Molecular form (H2) of the element.
[hydro- + G. -gen, producing]

hydrogen (H),

n a gaseous, univalent element. Its atomic number is 1 and its atomic weight is 1.008. It is the simplest and lightest of the elements and is normally a colorless, odorless, highly flammable diatonic gas.
hydrogen peroxide,
n an unstable compound of hydrogen and oxygen that is easily broken down into water and oxygen. A 3% solution is used as a mild antiseptic for the skin and mucous membranes; more concentrated solutions may be used as a whitening (bleaching) agent. May be used to reduce gingival inflammation, but may not eliminate the responsible bacteria.

hydrogen

a chemical element, atomic number 1, atomic weight 1.00797, symbol H. See Table 6. It exists as the mass 1 isotope (protium, or light or ordinary hydrogen), mass 2 isotope (deuterium, heavy hydrogen), and mass 3 isotope (tritium).

hydrogen bonding
weak electrostatic attraction between one electronegative atom and the hydrogen atom covalently linked to a second electronegative atom.
hydrogen breath test
detects hydrogen production as a product of bacterial fermentation of carbohydrates, an indicator of inflammatory bowel disease or carbohydrate malabsorption.
hydrogen cyanide
hydrocyanic acid.
heavy hydrogen
hydrogen having double the mass of ordinary hydrogen; deuterium.
hydrogen ion balance
hydrogen ion concentration
the degree of concentration of hydrogen ions (the acid element) in a solution. Its symbol is pH, and expresses the degree to which a solution is acidic or alkaline. The pH range extends from 0 to 14, pH 7 being neutral. A pH of less than 7 indicates acidity, above 7 indicates alkalinity. See also acid-base balance and ph.
hydrogen peroxide
H2O2, used in solution as an antibacterial agent. A 3% solution foams on touching skin or mucous membrane and appears to have a mechanical cleansing action.
hydrogen peroxide-based teat dips
hydrogen sulfide
an ill-smelling, colorless, poisonous gas, H2S; much used as a chemical reagent. Hydrogen sulfide is often present in gases from oil wells and from manure vats under slatted floor barns. Poisoning of cattle causes diarrhea, dehydration, dyspnea and death in convulsions. The feces are black and the breath smells of hydrogen sulfide. Called also hydrosulfuric acid. See also manure pit gas poisoning.
hydrogen swell
defective canned meat can. Can is distended due to production of hydrogen as a result of corrosion of the can surface.
References in periodicals archive ?
General Motors officials gave a progress report Monday on the company's efforts to create the automobiles of tomorrow by developing hydrogen fuel cell technology.
Although using steam to reform natural gas has proven thus far to be the cheapest way to produce commercial hydrogen, global production of natural gas is likely to peak sometime between 2020 and 2030, creating a second energy crisis on the heels of the oil crisis.
Assessing the level of hydrogen in the melt can be done in several ways.
Sandy" Thomas, president of Virginia-based H2Gen, is that the capital costs of a national hydrogen fueling infrastructure based on miniature natural gas reformers will be less than that of sustaining the existing gasoline fueling structure.
The company was also contracted to provide hydrogen sensors for the Lenningrad Nuclear Power Plant in Russia.
The tests were conducted on both Sr-modified and unmodified melts at various hydrogen levels and without grain refiners.
The extra electrons strip the two hydrogen atoms away from water's one oxygen atom, producing hydrogen fuel.
In a major switch, almost all of the world's carmakers are now focusing on direct storage of hydrogen gas on board the vehicle.
In 1776, Henry Cavendish, an English chemist and physicist who spent years studying the properties of hydrogen and carbon dioxide, discovered that hydrogen was a separate substance.
For most "real-world" situations, independent distinctions between hydrogen and shrinkage porosity have little practical importance, since effects of one on the other are inevitable.
HydroGen Corporation, through its wholly-owned subsidiary, HydroGen, LLC, is a developer of multi-megawatt fuel cell systems utilizing its proprietary 400-kilowatt phosphoric acid fuel cell (PAFC) technology.
gt;From the breakdown of biomass to the splitting of water using solar energy, researchers around the world have been exploring a host of renewable sources of hydrogen (SN: 10/12/02, p.