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oxygen

(Encyclopedia)oxygen, gaseous chemical element; symbol O; at. no. 8; interval in which at. wt. ranges 15.99903–15.99977; m.p. −218.4℃; b.p. −182.962℃; density 1.429 grams per liter at STP; valence −2. T...

group

(Encyclopedia)group, in mathematics, system consisting of a set of elements and a binary operation a∘b defined for combining two elements such that the following requirements are satisfied: (1) The set is closed ...

anglesite

(Encyclopedia)anglesite ăngˈgləsīt [key], pale green, blue, yellow-to-white, or colorless mineral, a sulfate of lead, PbSO4, that is formed by oxidation of galena, crystallizing in the orthorhombic system and o...

Anaximenes

(Encyclopedia)Anaximenes ănˌəksĭmˈĭnēz [key], Greek philosopher, 6th cent. b.c., last of the Milesian school founded by Thales. With Thales he held that a single element lay behind the diversity of nature, a...

dating

(Encyclopedia)dating, the determination of the age of an object, of a natural phenomenon, or of a series of events. There are two basic types of dating methods, relative and absolute. In relative dating, the tempor...

cerussite

(Encyclopedia)cerussite sērˈəsīt [key], colorless to white or gray mineral, sometimes yellowish or greenish, transparent to opaque, very brittle, crystallizing in the orthorhombic system and occurring also in g...

combustion

(Encyclopedia)combustion, rapid chemical reaction of two or more substances with a characteristic liberation of heat and light; it is commonly called burning. The burning of a fuel (e.g., wood, coal, oil, or natura...

Port Pirie

(Encyclopedia)Port Pirie pĭrˈē [key], city and municipality (2016 pop. 17,364), South Australia, S Australia, on an inlet of Spencer Gulf. It is a railroad center and has uranium refineries and smelting works fo...

galena

(Encyclopedia)galena gəlēˈnə [key] or lead glance, lustrous, blue-gray mineral crystallizing usually in cubes, sometimes in octahedrons. It is the most important ore and the principal source of lead. It consist...

oxidation and reduction

(Encyclopedia)oxidation and reduction, complementary chemical reactions characterized by the loss or gain, respectively, of one or more electrons by an atom or molecule. Originally the term oxidation was used to re...