hydrogen ion concentration
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1. increase in strength by evaporation.
2. the ratio of the mass or volume of a solute to the mass or volume of the solution or solvent.
3. intense mental focus.
hydrogen ion concentration see hydrogen ion concentration.
mass concentration the mass of a constituent substance divided by the volume of the mixture, as milligrams per liter (mg/l).
mean corpuscular hemoglobin concentration (MCHC) the average hemoglobin concentration in erythrocytes, conventionally expressed in “per cent,” meaning grams per deciliter of red blood cells, obtained by dividing the blood hemoglobin concentration (in g/dl) by the hematocrit (in l/l): MCHC = Hb/Hct.
minimal alveolar concentration (MAC) the concentration of anesthetic that at a pressure of 1 atmosphere produces immobility in 50 per cent of subjects exposed to a noxious stimulus.
minimal bactericidal concentration (MBC) the lowest concentration of a given antibiotic required to kill a specific organism.
minimal inhibitory concentration (MIC) the lowest concentration of a given antibiotic that inhibits the growth of a specific organism.
molar concentration the concentration of a substance expressed in terms of molarity.
concentration test a test of renal function based on the patient's ability to concentrate urine; see also fishberg concentration test.
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.