Nov 30, 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. Substances are either chemical …

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.

Nov 8, 2025 · The identification of pure substances and the analysis of chemical mixtures enable all other chemical disciplines to flourish. The importance of analytical chemistry has never been greater …

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 weapon, any of several chemical compounds, usually toxic agents, that are intended to kill, injure, or incapacitate. In modern warfare, chemical weapons were first used in World War I (1914–18).

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 …

5 days ago · Chemical industry, complex of processes, operations, and organizations engaged in the manufacture of chemicals and their derivatives. Raw materials include fossil fuels and inorganic …

Nov 28, 2025 · Professor and Associate Head, Department of Chemistry, University of Illinois at Urbana-Champaign. Author of Chemical Principles and many others.

Adrenochrome, unstable chemical compound formed by the oxidation of epinephrine (also known as adrenaline) and having the chemical formula C9H9NO3. Its name is a combination of the words …

Nov 1, 2025 · Gallium, chemical element of Group 13 (the boron group) of the periodic table. It liquefies just above room temperature. Gallium compounds, some of which form the basis for light-emitting …