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
hydrogen (H)
hydrogen (H) [hi´dro-jen]
hydrogen (H),
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.
hy·dro·gen (h  dr -jn)n. Symbol H A colorless, highly flammable gaseous element, the most abundant in the universe, used in ammonia and methanol synthesis, in the hydrogenation of organic materials, and as a reducing atmosphere. Atomic number 1. |
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.
Mentioned in: Magnetic Resonance Imaging
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.
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.
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
see acid-base 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
see teat dip.
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.
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