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.

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.

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, …

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 …

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 …

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 …

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 …

Nov 29, 2025 · The main problem concerned with the origin of the chemical elements is to decide to what extent the chemical composition of the stars seen today differs from the initial chemical …

But Haber was willing to pervert this chemical genius to help Germany win the war. And he set out to craft deadlier chemical weapons, leading a group of scientists the German military …

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 …