Sep 26, 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.

Oct 10, 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 …

Sep 23, 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 …

Sep 20, 2025 · Chemical formula, any of several kinds of expressions of the composition or structure of chemical compounds. The forms commonly encountered are empirical, molecular, …

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

Sep 12, 2025 · Chemical weapon - WMD, Toxins, Agents: Chemical weapons did not become true weapons of mass destruction (WMD) until they were introduced in their modern form in …

Oct 22, 2025 · gold (Au), chemical element, a dense lustrous yellow precious metal of Group 11 (Ib), Period 6, of the periodic table of the elements. Gold has several qualities that have made …

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.

Sep 15, 2025 · Krypton (Kr), chemical element, a rare gas of Group 18 (noble gases) of the periodic table, which forms relatively few chemical compounds. About three times heavier than …

People have invented ways to use the chemical energy of substances to power machines. For example, the chemical energy inside the substances in a battery can be transformed into …