
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.
Chemistry | Definition, Topics, Types, History, & Facts | Britannica
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 …
Chemical element | Definition, Origins, Distribution, & Facts
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 reaction | Definition, Equations, Examples, & Types
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 Definition & Meaning | Britannica Dictionary
CHEMICAL meaning: 1 : of or relating to chemistry; 2 : working by means of chemicals
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, …
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 …
Chemical element - Atomic Structure, Periodic Table, Properties ...
Nov 29, 2025 · The chemical characteristics of elements are intimately related to the number and arrangement of electrons in their atoms. Thus, elements are completely distinguishable from …
Chemical bonding - Ionic, Covalent, Compounds | Britannica
Oct 30, 2025 · The difference between the two classes gave rise to the view that there are two types of chemical bond. Electrolytes produce ions in solution; an ion is an electrically charged …
chemical reaction - Students | Britannica Kids | Homework Help
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 …