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  2. Chemical purity - Wikipedia

    en.wikipedia.org/wiki/Chemical_purity

    ACS grade is the highest level of purity, and meets the standards set by the American Chemical Society (ACS). The official descriptions of the ACS levels of purity is documented in the Reagent Chemicals publication, issued by the ACS. [3] [4] It is suitable for food and laboratory uses. Reagent grade is almost as stringent as the ACS grade.

  3. Occupational exposure banding - Wikipedia

    en.wikipedia.org/wiki/Occupational_exposure_banding

    The Hierarchy of Occupational Exposure Limits, of which occupational exposure banding is a member. Occupational exposure banding, also known as hazard banding, is a process intended to quickly and accurately assign chemicals into specific categories (bands), each corresponding to a range of exposure concentrations designed to protect worker health.

  4. List of chemical classifications - Wikipedia

    en.wikipedia.org/wiki/List_of_chemical...

    Chemical classification systems attempt to classify elements or compounds according to certain chemical functional or structural properties. Whereas the structural properties are largely intrinsic, functional properties and the derived classifications depend to a certain degree on the type of chemical interaction partners on which the function is exerted.

  5. Reactivity series - Wikipedia

    en.wikipedia.org/wiki/Reactivity_series

    Standard electrode potentials offer a quantitative measure of the power of a reducing agent, rather than the qualitative considerations of other reactive series. However, they are only valid for standard conditions: in particular, they only apply to reactions in aqueous solution. Even with this proviso, the electrode potentials of lithium and ...

  6. Metrology - Wikipedia

    en.wikipedia.org/wiki/Metrology

    Metrology is a wide reaching field, but can be summarized through three basic activities: the definition of internationally accepted units of measurement, the realisation of these units of measurement in practice, and the application of chains of traceability (linking measurements to reference standards).

  7. Level of measurement - Wikipedia

    en.wikipedia.org/wiki/Level_of_measurement

    Level of measurement or scale of measure is a classification that describes the nature of information within the values assigned to variables. [1] Psychologist Stanley Smith Stevens developed the best-known classification with four levels, or scales, of measurement: nominal , ordinal , interval , and ratio .

  8. Boiling points of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Boiling_points_of_the...

    Group → 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18; ↓ Period 1: H 2 20.271 K (−252.879 °C) He 4.222 K (−268.928 °C) 2: Li 1603 K (1330 °C) Be 2742 K ...

  9. Scoville scale - Wikipedia

    en.wikipedia.org/wiki/Scoville_scale

    This measurement is the highest dilution of a chili pepper extract at which heat can be detected by a taste panel." [ 5 ] [ 9 ] [ 10 ] A weakness of the Scoville organoleptic test is its imprecision due to human subjectivity, depending on the taster's palate and number of mouth heat receptors , which vary widely among subjects.