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Chemical compound | Definition, Examples, & Types | Britannica
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
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 reaction | Definition, Equations, Examples, & Types - Britannica
Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
Chemical element | Definition, Origins, Distribution, & Facts - 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. Learn more about the origins, distribution, and characteristics of chemical elements in this article.
Chemical formula | Definition, Types, Examples, & Facts | Britannica
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.
Chemical energy | Definition & Facts | Britannica
Chemical reactions differ from physical changes, which include changes of state, such as ice melting to water and water evaporating to vapor. If a physical change occurs, the physical properties of a substance will change, but its chemical identity will remain the same.
chemical reaction - Students | Britannica Kids | Homework Help
The substances in a chemical reaction may be chemical elements, molecules, or compounds. The substances present at the start of a chemical reaction are called the reactants; the substances formed by the reaction are called the products.
Chemical industry | Overview, Importance, & History | Britannica
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.
Chemical element - Atomic Structure, Periodic Table, Properties ...
The chemical characteristics of elements are intimately related to the number and arrangement of electrons in their atoms. Thus, elements are completely distinguishable from each other by their atomic numbers.
Chemical change | Britannica
A chemical change (that is, a chemical reaction) is one in which the organization of the atoms is altered. An example of a chemical reaction is the burning of methane in the presence of molecular oxygen (O2) to form carbon dioxide (CO2) and…
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