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mendelevium

(Encyclopedia)mendelevium mĕndəlāvˈēəm [key], artificially produced radioactive chemical element; symbol Md; at. no. 101; mass no. of most stable isotope 258; m.p. 827℃; b.p. and sp. gr. unknown; valence +1...

parthenogenesis

(Encyclopedia)parthenogenesis pärˌthənōjĕnˈəsĭs [key] [Gr.,=virgin birth], in biology, a form of reproduction in which the ovum develops into a new individual without fertilization. Natural parthenogenesis ...

cadmium

(Encyclopedia)cadmium kădˈmēəm [key] [from cadmia, Lat. for calamine, with which cadmium is found associated], metallic chemical element; symbol Cd; at. no. 48; at. wt. 112.411; m.p. 321℃; b.p. 765℃; sp. gr...

biochemistry

(Encyclopedia)biochemistry, science concerned chiefly with the chemistry of biological processes; it attempts to utilize the tools and concepts of chemistry, particularly organic and physical chemistry, for elucida...

scandium

(Encyclopedia)scandium skănˈdēəm [key], metallic chemical element; symbol Sc; at. no. 21; at. wt. 44.95591; m.p. 1,541℃; b.p. 2,831℃; sp. gr. 2.99 at 20℃; valence +3. Scandium is a soft silver-white metal...

Dale, Sir Henry Hallett

(Encyclopedia)Dale, Sir Henry Hallett, 1875–1968, English scientist. For his study of acetylcholine as agent in the chemical transmission of nerve impulses he shared with Otto Loewi the 1936 Nobel Prize in Physio...

Cherkasy

(Encyclopedia)Cherkasy chĭrkäˈsē [key], city (1989 pop. 290,000), capital of Cherkasy region, in central Ukraine, a port on the Dnieper River. Situated on the shore of the Kremenchuk Reservoir, Cherkasy has foo...

indicators, acid-base

(Encyclopedia)indicators, acid-base, organic compounds that, in aqueous solution, exhibit color changes indicative of the acidity or basicity of the solution. Common indicators include p-nitrophenol, which is color...

Graham, Thomas

(Encyclopedia)Graham, Thomas, 1805–69, Scottish chemist, best known for research in diffusion in both gases and liquids that led to his formulation of Graham's law. His discovery that certain substances (e.g., gl...

ammonium chloride

(Encyclopedia)ammonium chloride əmōˈnēəm klôrˈīd [key], chemical compound, NH4Cl, a white or colorless, odorless, water-soluble, cubic crystalline salt with a biting taste, commonly known as sal ammoniac. I...