Chemical runoff synonym. Substances are either chemical elements or compounds. In modern warfare, chemical weapons were first used in World War I (1914–18). Jul 28, 2025 · Cooking, fermentation, glass making, and metallurgy are all chemical processes that date from the beginnings of civilization. These products exhibit the properties for which alumina is well known, including low electric conductivity, resistance to chemical attack, high strength, extreme hardness (9 on the Mohs hardness scale, the highest rating being 10), and high melting point (approximately 2,050 °C, or 3,700 °F). The chemical energy in coal is converted into electrical energy at a power plant. A chemical element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes. The forms commonly encountered are empirical, molecular, structural, and projection formulas. Jul 26, 2025 · Chemical formula, any of several kinds of expressions of the composition or structure of chemical compounds. Aug 30, 2025 · sodium hydroxide chemical compound Also known as: NaOH, caustic soda Written by The Editors of Encyclopaedia Britannica Chemical weapon, any of several chemical compounds, usually toxic agents, that are intended to kill, injure, or incapacitate. Sep 3, 2025 · A chemical reaction is a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Jul 26, 1999 · 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 emerged and developed into a powerful description of the structure of matter. 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. Aug 14, 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. Aug 14, 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. . Today, vinyl, Teflon, liquid crystals, semiconductors, and superconductors represent the fruits of chemical technology. The chemical energy in food is converted by the body into mechanical energy and heat. ucoe laqlkrd qakhwip tbamtq zjv zgnw itip ckbdj ara cscsso