Chemical reaction | Definition, Equations, Examples, & Types
2024年10月28日 · A chemical reaction is a process in which one or more substances, also called reactants, are converted to one or more different substances, known as products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. The properties of ...
Chemical compound | Definition, Examples, & Types | Britannica
2024年10月18日 · Chemical compound, any substance composed of identical molecules consisting of atoms of two or more chemical elements. All the matter in the universe is composed of the atoms of more than 100 different chemical elements, which are found both in pure form and combined in chemical compounds.
Chemistry | Definition, Topics, Types, History, & Facts | Britannica
6 天之前 · Cooking, fermentation, glass making, and metallurgy are all chemical processes that date from the beginnings of civilization. Today, vinyl, Teflon, liquid crystals, semiconductors , and superconductors represent the fruits of chemical technology.
Chemical element | Definition, Origins, Distribution, & Facts
A chemical element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. Learn more about the origins, distribution, and characteristics of …
Chemical industry | Overview, Importance, & History | Britannica
2024年10月11日 · Chemical industry, complex of processes, operations, and organizations engaged in the manufacture of chemicals and their derivatives. Raw materials include fossil fuels and inorganic chemicals. An average chemical product is passed from factory to factory several times before it emerges into the market.
list of chemical elements - Encyclopedia Britannica
A chemical element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. Here, the elements are ordered alphabetically.
Chemical Definition & Meaning | Britannica Dictionary
CHEMICAL meaning: 1 : of or relating to chemistry; 2 : working by means of chemicals
Chemical bonding | Definition, Types, & Examples | Britannica
2024年10月30日 · Chemical bonding, any of the interactions that account for the association of atoms into molecules, ions, crystals, and other species. When atoms approach one another, their electrons interact and tend to distribute themselves in space so that the total energy is lower than it would be in any alternative arrangement.
Chemical formula | Definition, Types, Examples, & Facts | Britannica
2024年10月19日 · chemical formula, any of several kinds of expressions of the composition or structure of chemical compounds. The forms commonly encountered are empirical, molecular, structural, and projection formulas.
Calcium | Definition, Properties, & Compounds | Britannica
2024年11月12日 · calcium (Ca), chemical element, one of the alkaline-earth metals of Group 2 (IIa) of the periodic table. It is the most abundant metallic element in the human body and the fifth most abundant element in Earth’s crust.