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surface chemistry

(Encyclopedia)surface chemistry, study of chemical reactions in which the reactants are first adsorbed onto a surface medium (see adsorption) that then acts as a catalyst for the reaction; after the reaction the pr...

benzaldehyde

(Encyclopedia)benzaldehyde bĕnˌzēnkärˈbənəl [key], C6H5CHO, colorless liquid aldehyde with a characteristic almond odor. It boils at 180℃, is soluble in ethanol, but is insoluble in water. It is formed by ...

atomic weight

(Encyclopedia)atomic weight, mean (weighted average) of the masses of all the naturally occurring isotopes of a chemical element, as contrasted with atomic mass, which is the mass of any individual isotope. Althoug...

Oppenheimer, J. Robert

(Encyclopedia)Oppenheimer, J. Robert ŏpˈənhīˌmər [key], 1904–67, American physicist, b. New York City, grad. Harvard (B.A., 1925), Ph.D. Univ. of Göttingen, 1927. He taught at the Univ. of California and t...

rare-earth metals

(Encyclopedia)rare-earth metals, in chemistry, group of metals including those of the lanthanide series and actinide series and usually yttrium, sometimes scandium and thorium, and rarely zirconium. Promethium, whi...

Thomson, Sir Joseph John

(Encyclopedia)Thomson, Sir Joseph John, 1856–1940, English physicist. From 1884 to 1919 he was Cavendish professor of experimental physics at Cambridge. J. J. Thomson was one of the founders of modern physics. Wi...

copernicium

(Encyclopedia)copernicium, artificially produced radioactive chemical element; symbol Cn; at. no. 112; mass number of most stable isotope 285; m.p., b.p., sp. gr., and valence unknown. Situated in Group 12 of the p...

nitrobenzene

(Encyclopedia)nitrobenzene, C6H5NO2, very poisonous, flammable, pale yellow, liquid aromatic compound with an odor like that of bitter almonds. It is sometimes called oil of mirbane or nitrobenzol. Nitrobenzene mel...

mineral water

(Encyclopedia)mineral water, spring water containing various mineral salts, especially the carbonates, chlorides, phosphates, silicates, sulfides, and sulfates of calcium, iron, lithium, magnesium, potassium, sodiu...

Langmuir, Irving

(Encyclopedia)Langmuir, Irving lăngˈmyo͞or [key], 1881–1957, American chemist, b. Brooklyn, N.Y. Associated (1909–50) with the research laboratory of the General Electric Company, he introduced atomic-hydrog...