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hydrogen cyanide

(Encyclopedia)hydrogen cyanide, HCN, colorless, volatile, and extremely poisonous chemical compound whose vapors have a bitter almond odor. It melts at −14℃ and boils at 26℃. It is miscible in all proportions...

gas

(Encyclopedia)gas, in physics, one of the three commonly recognized states of matter, the other two being solid and liquid. A substance in the gaseous state has neither definite shape nor definite volume. Like liqu...

methionine

(Encyclopedia)CE5 methionine mĕthīˈənēn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Only the L-stereoisomer appears in mammalian protein. It is one of the several e...

membrane

(Encyclopedia)membrane, structure composed mostly of lipid and protein that forms the external boundary of cells and of major structures within cells. Membrane organization is based on a sheet two molecules thick�...

asthma

(Encyclopedia)asthma ăzˈmə, ăsˈ– [key], chronic inflammatory respiratory disease characterized by periodic attacks of wheezing, shortness of breath, and a tight feeling in the chest. A cough producing sticky...

naphthol

(Encyclopedia)CE5 naphthol năfˈthôl [key], C10H7OH, either of two crystalline monohydric alcohols. The naphthols are position isomers, differing in the location of the hydroxyl group, –OH, on the carbon ske...

nobelium

(Encyclopedia)nobelium nōbēˈlēəm [key], artificially produced radioactive chemical element; symbol No; at. no. 102; mass no. of most stable isotope 259; m.p. 827℃; b.p. and density unknown; valence +2, +3. I...

liquid air

(Encyclopedia)liquid air, ordinary air that has been liquefied by compression and cooling to extremely low temperatures (see liquefaction). Its commercial preparation involves purification by washing to remove solu...

sugar

(Encyclopedia)sugar, compound of carbon, hydrogen, and oxygen belonging to a class of substances called carbohydrates. Sugars fall into three groups: the monosaccharides, disaccharides, and trisaccharides. The mono...

snowball earth

(Encyclopedia)snowball earth, hypothesized condition in which the earth was covered completely by ice during several periods in the Proterozoic. The hypothesis was originally developed to explain evidence of the co...