
Chemistry | Definition, Topics, Types, History, & Facts | Britannica
Nov 8, 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 compound | Definition, Examples, & Types | Britannica
Nov 11, 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.
Chemical reaction | Definition, Equations, Examples, & Types - Britannica
6 days ago · 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
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 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
The chemical energy in food is converted by the body into mechanical energy and heat. The chemical energy in coal is converted into electrical energy at a power plant. The chemical energy in a battery …
Chemical bonding | Definition, Types, & Examples | Britannica
Oct 30, 2025 · This article begins by describing the historical evolution of the current understanding of chemical bonding and then discusses how modern theories of the formation of chemical bonds have …
Chemical weapon - Nerve Agents, Toxins, Warfare | Britannica
Chemical weapon - Nerve Agents, Toxins, Warfare: The most lethal and important chemical weapons contain nerve agents, which affect the transmission of impulses through the nervous system.
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 weapon | Convention, Definition, List, World War I, World …
In modern warfare, chemical weapons were first used in World War I (1914–18). Like nuclear and biological weapons, chemical weapons are often classified as weapons of mass destruction.