
Chemical Definition & Meaning | Britannica Dictionary
plural chemicals Britannica Dictionary definition of CHEMICAL [count] : a substance (such as an element or compound) that is made by a chemical process
Chemical reaction | Definition, Equations, Examples, & Types - Britannica
Apr 17, 2026 · 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 …
Chemical industry | Overview, Importance, & History | Britannica
Chemical industry, complex of processes, operations, and organizations engaged in the manufacture of chemicals and their derivatives. Raw materials include fossil fuels and inorganic chemicals. An …
Cellular respiration | Definition, Equation, Cycle, Process, Reactants ...
Apr 2, 2026 · Cellular respiration, the process by which organisms combine oxygen with foodstuff molecules, diverting the chemical energy in these substances into life-sustaining activities and …
Chemistry - Analysis, Reactions, Compounds | Britannica
Apr 8, 2026 · Chemistry - Analysis, Reactions, Compounds: Most of the materials that occur on Earth, such as wood, coal, minerals, or air, are mixtures of many different and distinct chemical substances. …
Chemical engineering | Processes, Principles & Applications | Britannica
chemical engineering, the development of processes and the design and operation of plants in which materials undergo changes in their physical or chemical state. Applied throughout the process …
Photosynthesis | Definition, Formula, Process, Diagram, Reactants ...
Mar 21, 2026 · Photosynthesis is the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is …
Alcohol | Definition, Structure, Classification, Commercial Uses ...
4 days ago · An alcohol is an organic compound with one or more hydroxyl groups attached to a carbon atom of an alkyl group. Alcohols may be considered as organic derivatives of water, in which a …
Water | Definition, Chemical Formula, Structure, Molecule, & Facts ...
Mar 20, 2026 · Water, substance composed of the chemical elements hydrogen and oxygen and existing in gaseous, liquid, and solid states. It is one of the most plentiful of compounds and has the …
Helium | Definition, Properties, Uses, & Facts | Britannica
Mar 24, 2026 · Helium is a chemical element, an inert gas of Group 18 (noble gases) of the periodic table. The second lightest element, helium is a colorless, odorless, and tasteless gas that becomes …