Columbia Encyclopedia

Search results

500 results found

kinetic-molecular theory of gases

(Encyclopedia)kinetic-molecular theory of gases, physical theory that explains the behavior of gases on the basis of the following assumptions: (1) Any gas is composed of a very large number of very tiny particles ...

pH

(Encyclopedia)pH, range of numbers expressing the relative acidity or alkalinity of a solution. In general, pH values range from 0 to 14. The pH of a neutral solution, i.e., one which is neither acidic nor alkaline...

compound

(Encyclopedia)compound, in chemistry, a substance composed of atoms of two or more elements in chemical combination, occurring in a fixed, definite proportion and arranged in a fixed, definite structure. A compound...

chemical analysis

(Encyclopedia)chemical analysis, the study of the chemical composition and structure of substances. More broadly, it may be considered the corpus of all techniques whereby any exact chemical information is obtained...

formic acid

(Encyclopedia)formic acid or methanoic acid mĕthˌənōˈĭk [key], HCO2H, a colorless, corrosive liquid with a sharp odor; it boils at 100.7℃ and solidifies at 8.4℃. It has the lowest molecular weight and is ...

Natta, Giulio

(Encyclopedia)Natta, Giulio, 1903–79, Italian chemist, Ph.D. the Polytechnic of Milan, 1924. Natta held brief appointments at several academic institutions, including the Univ. of Pavia (1933–35), the Univ. of ...

mercaptan

(Encyclopedia)mercaptan thīˈōl [key], any of a class of organic compounds containing the group –SH bonded to a carbon atom. The volatile low-molecular-weight mercaptans have disagreeable odors. Mercaptans are ...

Shirakawa, Hideki

(Encyclopedia)Shirakawa, Hideki, 1936–, Japanese chemist, Ph.D. Tokyo Institute of Technology, 1966. Shirakawa was a research assistant at the Tokyo Institute of Technology from 1966 to 1979. He then taught at th...

Carothers, Wallace Hume

(Encyclopedia)Carothers, Wallace Hume kərŭᵺˈərz [key], 1896–1937, American chemist, b. Burlington, Iowa. He received his doctorate at the Univ. of Illinois in 1924, then taught organic chemistry there and a...

erythromycin

(Encyclopedia)erythromycin ĭrĭthˌrōmīˈsĭn [key], any of several related antibiotic drugs produced by bacteria of the genus Streptomyces (see antibiotic). Erythromycin is most effective against gram-positive ...