
Chemical compound | Definition, Examples, & Types | Britannica
Dec 16, 2025 · 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
Dec 26, 2025 · Cooking, fermentation, glass making, and metallurgy are all chemical processes that date from the beginnings of civilization. Today, vinyl, Teflon, liquid crystals, semiconductors, and …
Chemical reaction | Definition, Equations, Examples, & Types - Britannica
Nov 30, 2025 · Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
Chemical Definition & Meaning | Britannica Dictionary
CHEMICAL meaning: 1 : of or relating to chemistry; 2 : working by means of chemicals
Chemical element | Definition, Origins, Distribution, & Facts - Britannica
Nov 29, 2025 · 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 …
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 …
Chemical formula | Definition, Types, Examples, & Facts | Britannica
Nov 1, 2025 · 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 …
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 …
Carbonate | Ionic Bonding, Salts & Minerals | Britannica
Dec 24, 2025 · Carbonate, any member of two classes of chemical compounds derived from carbonic acid or carbon dioxide (q.v.). The inorganic carbonates are salts of carbonic acid (H2CO3), …
Oxalic acid | Formula, Uses, & Facts | Britannica
Dec 19, 2025 · oxalic acid chemical compound Also known as: ethanedioic acid Britannica Editors Dec. 19, 2025 • History