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  1. Chemistry | Definition, Topics, Types, History, & Facts | Britannica

    Jun 16, 2025 · Most of the materials that occur on Earth, such as wood, coal, minerals, or air, are mixtures of many different and distinct chemical substances. Each pure chemical substance …

  2. Chemical Definition & Meaning | Britannica Dictionary

    CHEMICAL meaning: 1 : of or relating to chemistry; 2 : working by means of chemicals

  3. Chemical reaction | Definition, Equations, Examples, & Types

    May 12, 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 …

  4. Chemical compound | Definition, Examples, & Types | Britannica

    4 days ago · Chemical compound, any substance composed of identical molecules consisting of atoms of two or more chemical elements. All the matter in the universe is composed of the …

  5. Chemical element | Definition, Origins, Distribution, & Facts

    Apr 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 …

  6. Chemical formula | Definition, Types, Examples, & Facts | Britannica

    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 …

  7. chemical element - Students | Britannica Kids | Homework Help

    Any substance that cannot be decomposed into simpler substances by ordinary chemical processes is defined as a chemical element. Only 94 such substances are known to exist in …

  8. list of chemical elements - Encyclopedia Britannica

    May 10, 2015 · A chemical element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which …

  9. chemical energy - Kids | Britannica Kids | Homework Help

    Chemical energy is a form of potential energy that is in all substances. Food is the most important source of chemical energy for living things. The chemical energy in food is converted, or …

  10. chemical reaction - Students | Britannica Kids | Homework Help

    To describe chemical reactions, scientists use chemical equations, which make use of symbols and formulas for elements and compounds. The chemical equation for the reaction between …

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