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  2. Matter - Wikipedia

    en.wikipedia.org/wiki/Matter

    Different fields of science use the term matter in different, and sometimes incompatible, ways. ... Pure water is an example of a ... A definition of "matter" based ...

  3. Chemistry - Wikipedia

    en.wikipedia.org/wiki/Chemistry

    Chemistry is the scientific study of the properties and behavior of matter. [1] It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances.

  4. Chemical substance - Wikipedia

    en.wikipedia.org/wiki/Chemical_substance

    Pure water is an example of a chemical substance, with a constant composition of two hydrogen atoms bonded to a single oxygen atom (i.e. H 2 O). The atomic ratio of hydrogen to oxygen is always 2:1 in every molecule of water. Pure water will tend to boil near 100 °C

  5. Branches of science - Wikipedia

    en.wikipedia.org/wiki/Branches_of_science

    The science of matter is also addressed by physics, but while physics takes a more general and fundamental approach, chemistry is more specialized, being concerned by the composition, behavior (or reaction), structure, and properties of matter, as well as the changes it undergoes during chemical reactions.

  6. Chemical impurity - Wikipedia

    en.wikipedia.org/wiki/Chemical_impurity

    In chemistry and materials science, impurities are chemical substances inside a confined amount of liquid, gas, or solid. They differ from the chemical composition of the material or compound. [1] Firstly, a pure chemical should appear in at least one chemical phase and can also be characterized by its phase diagram.

  7. Gas - Wikipedia

    en.wikipedia.org/wiki/Gas

    Drifting smoke particles indicate the movement of the surrounding gas.. Gas is one of the four fundamental states of matter.The others are solid, liquid, and plasma. [1] A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide).

  8. Mole (unit) - Wikipedia

    en.wikipedia.org/wiki/Mole_(unit)

    The International Bureau of Weights and Measures defined the mole as "the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilograms of carbon-12." Thus, by that definition, one mole of pure 12 C had a mass of exactly 12 g. [15] [5] The four different definitions were equivalent to within 1%.

  9. Material - Wikipedia

    en.wikipedia.org/wiki/Material

    Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geological origin or biological function. Materials science is the study of materials, their properties and their applications.