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  2. Chemical impurity - Wikipedia

    en.wikipedia.org/wiki/Chemical_impurity

    Firstly, a pure chemical should appear in at least one chemical phase and can also be characterized by its phase diagram. Secondly, a pure chemical should prove to be homogeneous (i.e., a uniform substance that has the same composition throughout the material [2]). The perfect pure chemical will pass all attempts to separate and purify it further.

  3. List of alchemical substances - Wikipedia

    en.wikipedia.org/wiki/List_of_alchemical_substances

    Plumbago – a mineral, graphite; not discovered in pure form until 1564; Powder of Algaroth – antimony oxychloride, formed by precipitation when a solution of butter of antimony and spirit of salt is poured into water. Purple of Cassius – formed by precipitating a mixture of gold, stannous and stannic chlorides, with alkali. Used for glass ...

  4. BBC Bitesize - Wikipedia

    en.wikipedia.org/wiki/BBC_Bitesize

    BBC Bitesize, [1] also abbreviated to Bitesize, is the BBC's free online study support resource for school-age pupils in the United Kingdom. It is designed to aid pupils in both schoolwork and, for older pupils, exams .

  5. Chemical substance - Wikipedia

    en.wikipedia.org/wiki/Chemical_substance

    While the term chemical substance is a precise technical term that is synonymous with chemical for chemists, the word chemical is used in general usage to refer to both (pure) chemical substances and mixtures (often called compounds), [14] and especially when produced or purified in a laboratory or an industrial process.

  6. Material - Wikipedia

    en.wikipedia.org/wiki/Material

    A material is a substance or mixture of substances that constitutes an object.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.

  7. Reactivity (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Reactivity_(chemistry)

    In pure compounds, reactivity is regulated by the physical properties of the sample. For instance, grinding a sample to a higher specific surface area increases its reactivity. In impure compounds, the reactivity is also affected by the inclusion of contaminants. In crystalline compounds, the crystalline form can also affect reactivity. However ...

  8. Chemical element - Wikipedia

    en.wikipedia.org/wiki/Chemical_element

    In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the same atomic number, or number of protons. Nuclear scientists, however, define a pure element as one that consists of only one isotope. [18] For example, a copper wire is 99.99% chemically pure if 99.99% of its atoms are copper, with 29 protons each.

  9. Separation process - Wikipedia

    en.wikipedia.org/wiki/Separation_process

    A separation process is a method that converts a mixture or a solution of chemical substances into two or more distinct product mixtures, [1] a scientific process of separating two or more substances in order to obtain purity. At least one product mixture from the separation is enriched in one or more of the source mixture's constituents.