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  2. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    At 1 ppm the solution is a very pale yellow. As the concentration increases the colour becomes a more vibrant yellow, then orange, with the final 10,000 ppm a deep red colour. 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. Dilution (equation) - Wikipedia

    en.wikipedia.org/wiki/Dilution_(equation)

    The equation can only be applied when the purged volume of vapor or gas is replaced with "clean" air or gas. For example, the equation can be used to calculate the time required at a certain ventilation rate to reduce a high carbon monoxide concentration in a room.

  4. 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

  5. Gutmann–Beckett method - Wikipedia

    en.wikipedia.org/wiki/Gutmann–Beckett_method

    Gutmann, a chemist renowned for his work on non-aqueous solvents, described an acceptor-number scale for solvent Lewis acidity [4] with two reference points relating to the 31 P NMR chemical shift of Et 3 PO in the weakly Lewis acidic solvent hexane (δ = 41.0 ppm, AN 0) and in the strongly Lewis acidic solvent SbCl 5 (δ = 86.1 ppm, AN 100).

  6. Clarke number - Wikipedia

    en.wikipedia.org/wiki/Clarke_number

    If the concentration of a commodity in an ore X is [ppm], and the "clarke" of that commodity is [ppm], then "the clarke of concentration" of that commodity X is = (dimensionless). The value represents the degree to which the commodity is concentrated from crustal abundances to the ore by natural geochemical processes; a clue for whether the ...

  7. Air pollutant concentrations - Wikipedia

    en.wikipedia.org/wiki/Air_pollutant_concentrations

    where: mg/m 3 = milligrams of pollutant per cubic meter of air at sea level atmospheric pressure and T: ppmv = air pollutant concentration, in parts per million by volume

  8. Permissible exposure limit - Wikipedia

    en.wikipedia.org/wiki/Permissible_exposure_limit

    [9] [10] Organizations may implement stricter guidelines for chemical use and exposure, but OSHA guidelines must be followed at the minimum. [ 11 ] [ 10 ] Permissible Exposure Limits are time-weighted average, meaning that a worker may be exposed to higher concentrations of the chemical at different times of the work shift.

  9. Equivalent concentration - Wikipedia

    en.wikipedia.org/wiki/Equivalent_concentration

    There are three common types of chemical reaction where normality is used as a measure of reactive species in solution: In acid-base chemistry, normality is used to express the concentration of hydronium ions (H 3 O +) or hydroxide ions (OH −) in a solution. Here, ⁠ 1 / f eq ⁠ is an integer value. Each solute can produce one or more ...