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  2. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    At 10 000 ppm the solution is a deep red colour. As the concentration decreases the colour becomes orange, then a vibrant yellow, with the final 1 ppm sample a very pale yellow. In science and engineering , the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities , e.g. mole fraction or ...

  3. Acid value - Wikipedia

    en.wikipedia.org/wiki/Acid_value

    In chemistry, acid value (AV, acid number, neutralization number or acidity) is a number used to quantify the acidity of a given chemical substance.It is the quantity of base (usually potassium hydroxide (KOH)), expressed as milligrams of KOH required to neutralize the acidic constituents in 1 gram of a sample.

  4. Total dissolved solids - Wikipedia

    en.wikipedia.org/wiki/Total_dissolved_solids

    where TDS is expressed in mg/L and EC is the electrical conductivity in microsiemens per centimeter at 25 °C. The conversion factor k e varies between 0.55 and 0.8. [5] Some TDS meters use an electrical conductivity measurement to the ppm using the above formula. Regarding units, 1 ppm indicates 1 mg of dissolved solids per 1,000 g of water. [6]

  5. Air pollutant concentrations - Wikipedia

    en.wikipedia.org/wiki/Air_pollutant_concentrations

    As an example, a measured particulates concentration of 200 mg/m 3 in a dry gas that has a measured 8 volume % CO 2 is: 200 × ( 12 ÷ 8 ) = 300 mg/m 3. when corrected to a dry gas having a specified reference CO 2 content of 12 volume %.

  6. Saponification value - Wikipedia

    en.wikipedia.org/wiki/Saponification_value

    1000 is the conversion factor for milligrams to grams 56.1 is the molar mass of KOH. [7] 38.049 is the molecular mass of glycerol backbone. For instance, triolein, a triglyceride occurring in many fats and oils, has three oleic acid residues esterified to a molecule of glycerol with a total MW of 885.4 (g / mol).

  7. Alkalinity - Wikipedia

    en.wikipedia.org/wiki/Alkalinity

    Certain ions, including Na +, K +, Ca 2+, Mg 2+, Cl −, SO 2− 4, and NO − 3 are "conservative" such that they are unaffected by changes in temperature, pressure or pH. [8] Others such as HCO − 3 are affected by changes in pH, temperature, and pressure. By isolating the conservative ions on one side of this charge balance equation, the ...

  8. Solubility chart - Wikipedia

    en.wikipedia.org/wiki/Solubility_chart

    The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.

  9. Conversion of units - Wikipedia

    en.wikipedia.org/wiki/Conversion_of_units

    The factor–label method can convert only unit quantities for which the units are in a linear relationship intersecting at 0 (ratio scale in Stevens's typology). Most conversions fit this paradigm. An example for which it cannot be used is the conversion between the Celsius scale and the Kelvin scale (or the Fahrenheit scale). Between degrees ...