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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. 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

  4. dGH - Wikipedia

    en.wikipedia.org/wiki/DGH

    In water testing hardness is often measured in parts per million (ppm), where one part per million is defined as one milligram of calcium carbonate (CaCO 3) per litre of water. Consequently, 1 dGH corresponds to 10 ppm CaO but 17.848 ppm CaCO 3 which has a molar mass of 100.09 g/mol.

  5. Carbonate hardness - Wikipedia

    en.wikipedia.org/wiki/Carbonate_hardness

    In a solution where only CO 2 affects the pH, carbonate hardness can be used to calculate the concentration of dissolved CO 2 in the solution with the formula CO 2 = 3 × KH × 10 (7-pH), where KH is degrees of carbonate hardness and CO 2 is given in ppm by weight.

  6. Vapor pressures of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Vapor_pressures_of_the...

    David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition, online version. CRC Press. Boca Raton, Florida, 2003; Section 4, Properties of the Elements and Inorganic Compounds; Vapor Pressure of the Metallic Elements The equations reproduce the observed pressures to an accuracy of ±5% or better.

  7. dKH - Wikipedia

    en.wikipedia.org/wiki/DKH

    As a unit 1 dKH is the same as 1 °dH which is equal to approximately 0.1786 mmol/L or 17.86 milligrams (mg) of calcium carbonate per litre of water, i.e. 17.86 ppm. [ citation needed ]

  8. 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.

  9. Gibbs–Helmholtz equation - Wikipedia

    en.wikipedia.org/wiki/Gibbs–Helmholtz_equation

    The definition of the Gibbs function is = + where H is the enthalpy defined by: = +. Taking differentials of each definition to find dH and dG, then using the fundamental thermodynamic relation (always true for reversible or irreversible processes): = where S is the entropy, V is volume, (minus sign due to reversibility, in which dU = 0: work other than pressure-volume may be done and is equal ...