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  2. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water.The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution.

  3. Total dissolved solids - Wikipedia

    en.wikipedia.org/wiki/Total_dissolved_solids

    Bottled mineral water usually contains higher TDS levels than tap water.. Total dissolved solids (TDS) is a measure of the dissolved combined content of all inorganic and organic substances present in a liquid in molecular, ionized, or micro-granular (colloidal sol) suspended form.

  4. Grain per gallon - Wikipedia

    en.wikipedia.org/wiki/Grain_per_gallon

    Water chemists measure water impurities in parts per million (ppm). For understandability, hardness ordinarily is expressed in grains of hardness per gallon of water (gpg). The two systems can be converted mathematically.

  5. Orders of magnitude (molar concentration) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(molar...

    inhaled carbon monoxide induces unconsciousness in 2–3 breaths and death in < 3 min (12 800 ppm) [15] 10 −3: mM 0.32–32 mM: normal range of hydronium ions in stomach acid (pH 1.5–3.5) [16] 5.5 mM: upper bound for healthy blood glucose when fasting [17] 7.8 mM: upper bound for healthy blood glucose 2 hours after eating [17] 10 −2: cM 20 mM

  6. Volume fraction - Wikipedia

    en.wikipedia.org/wiki/Volume_fraction

    The volume of such a mixture is slightly less than the sum of the volumes of the components. Thus, by the above definition, the term "40% alcohol by volume" refers to a mixture of 40 volume units of ethanol with enough water to make a final volume of 100 units, rather than a mixture of 40 units of ethanol with 60 units of water.

  7. Concentration - Wikipedia

    en.wikipedia.org/wiki/Concentration

    In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: mass concentration , molar concentration , number concentration , and volume concentration . [ 1 ]

  8. pCO2 - Wikipedia

    en.wikipedia.org/wiki/PCO2

    The pCO 2 of Earth's atmosphere has risen from approximately 280 ppm (parts-per-million) to a mean 2019 value of 409.8 ppm as a result of anthropogenic release of carbon dioxide from fossil fuel burning. [citation needed] This is the highest atmospheric concentration to have existed on Earth for at least the last 800,000 years. [1]

  9. PPM - Wikipedia

    en.wikipedia.org/wiki/PPM

    Temperature coefficient, in parts per million per Kelvin (ppm/K) or per degree Celsius (ppm/C) Topics referred to by the same term This disambiguation page lists articles associated with the title PPM .