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  2. Prices of chemical elements - Wikipedia

    en.wikipedia.org/wiki/Prices_of_chemical_elements

    This is a list of prices of chemical elements. Listed here are mainly average market prices for bulk trade of commodities. Data on elements' abundance in Earth's crust is added for comparison. As of 2020, the most expensive non-synthetic element by both mass and volume is rhodium.

  3. Oxygen-free copper - Wikipedia

    en.wikipedia.org/wiki/Oxygen-free_copper

    This is a 99.99% pure copper with 0.0005% oxygen content. It achieves a minimum 101% IACS conductivity rating. This copper is finished to a final form in a carefully regulated, oxygen-free environment. Silver (Ag) is considered an impurity in the OFE chemical specification. This is also the most expensive of the three grades listed here.

  4. Abundance of the chemical elements - Wikipedia

    en.wikipedia.org/wiki/Abundance_of_the_chemical...

    The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.

  5. Nines (notation) - Wikipedia

    en.wikipedia.org/wiki/Nines_(notation)

    For example, a N2.0 gas is 99% (two nines) pure and 1% impurities by volume; a N6.0 gas is 99.9999% (six nines) pure, with 1 part per million (1 ppm or 1 vpm, volume per million) impurities. [7] Intermediate values indicate the digit following the last nine. For example, N4.6 estimates a purity level of 99.996% (four nines followed by a six). [7]

  6. 97.5th percentile point - Wikipedia

    en.wikipedia.org/wiki/97.5th_percentile_point

    In Table 1 of the same work, he gave the more precise value 1.959964. [12] In 1970, the value truncated to 20 decimal places was calculated to be 1.95996 39845 40054 23552... [13] [14] The commonly used approximate value of 1.96 is therefore accurate to better than one part in 50,000, which is more than adequate for applied work.

  7. List of thermal conductivities - Wikipedia

    en.wikipedia.org/wiki/List_of_thermal_conductivities

    TPRC Tin is well annealed 99.999+% pure white tin with residual electrical resistivity ρ 0 =0.000120, 0.0001272 & 0.000133 μΩ cm respectively for the single crystal along directions perpendicular and parallel to the c axis and for polycrystalline tin P. The recommended values are thought to be accurate to within 3% near room temperature and ...

  8. Chemical purity - Wikipedia

    en.wikipedia.org/wiki/Chemical_purity

    In chemistry, chemical purity is the measurement of the amount of impurities found in a sample.Several grades of purity are used by the scientific, pharmaceutical, and industrial communities.

  9. We are the 99% - Wikipedia

    en.wikipedia.org/wiki/We_are_the_99%

    It reflects the belief that "the 99%" are paying the price for the mistakes of a tiny minority within the upper class. the 1% is not necessarily a reference to top 1% of wage earners, but a reference to the top 1% of individuals by net worth, whose earned wages are only a fraction of their total sources of wealth. [1]