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  2. Glossary of chemistry terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_chemistry_terms

    Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...

  3. Periodic trends - Wikipedia

    en.wikipedia.org/wiki/Periodic_trends

    In chemistry, periodic trends are specific patterns present in the periodic table that illustrate different aspects of certain elements when grouped by period and/or group. They were discovered by the Russian chemist Dmitri Mendeleev in 1863.

  4. Scientific law - Wikipedia

    en.wikipedia.org/wiki/Scientific_law

    Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. [1] The term law has diverse usage in many cases (approximate, accurate, broad, or narrow) across all fields of natural science (physics, chemistry, astronomy, geoscience, biology).

  5. Femtochemistry - Wikipedia

    en.wikipedia.org/wiki/Femtochemistry

    Femtochemistry is the area of physical chemistry that studies chemical reactions on extremely short timescales (approximately 10 −15 seconds or one femtosecond, hence the name) in order to study the very act of atoms within molecules (reactants) rearranging themselves to form new molecules (products).

  6. Liesegang rings - Wikipedia

    en.wikipedia.org/wiki/Liesegang_rings

    Liesegang rings - Silver-chromate precipitate pattern in a layer of gelatine Some Liesegang Rings. Liesegang rings (/ ˈ l iː z ə ɡ ɑː ŋ /) are a phenomenon seen in many, if not most, chemical systems undergoing a precipitation reaction under certain conditions of concentration and in the absence of convection.

  7. Fluxional molecule - Wikipedia

    en.wikipedia.org/wiki/Fluxional_molecule

    In chemistry and molecular physics, fluxional (or non-rigid) molecules are molecules that undergo dynamics such that some or all of their atoms interchange between symmetry-equivalent positions. [1] Because virtually all molecules are fluxional in some respects, e.g. bond rotations in most organic compounds , the term fluxional depends on the ...

  8. SMILES arbitrary target specification - Wikipedia

    en.wikipedia.org/wiki/Smiles_arbitrary_target...

    In the following example, recursive SMARTS notation is used to combine acid oxygen and tetrazole nitrogen in a definition of oxygen atoms that are likely to be anionic under normal physiological conditions. [$([OH][C,S,P]=O),$([nH]1nnnc1)] The SMARTS above would only match the acid hydroxyl and the tetrazole N−H.

  9. Law of multiple proportions - Wikipedia

    en.wikipedia.org/wiki/Law_of_multiple_proportions

    For example, if one tried to demonstrate it using the hydrocarbons decane (C 10 H 22) and undecane (C 11 H 24), one would find that 100 grams of carbon could react with 18.46 grams of hydrogen to produce decane or with 18.31 grams of hydrogen to produce undecane, for a ratio of hydrogen masses of 121:120, which is hardly a ratio of "small ...