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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 ...
Atmospheric pollutant concentrations expressed as mass per unit volume of atmospheric air (e.g., mg/m 3, μg/m 3, etc.) at sea level will decrease with increasing altitude because the atmospheric pressure decreases with increasing altitude.
Some express the concentrations as ppmv (parts per million by volume) and some express the concentrations as mg/m 3 (milligrams per cubic meter), while others require adjusting or correcting the concentrations to reference conditions of moisture content, oxygen content or carbon dioxide content.
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.
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]
However, the names of all SI mass units are based on gram, rather than on kilogram; thus 10 3 kg is a megagram (10 6 g), not a *kilokilogram. The tonne (t) is an SI-compatible unit of mass equal to a megagram (Mg), or 10 3 kg. The unit is in common use for masses above about 10 3 kg and is often used with SI prefixes.
For the drugs administered by oral and dermal route, the units of threshold dose are mg/kg body-weight/day (dose of the drug in mg per body weight in kg per day) or ppm (parts per million), while the threshold dose of drugs by inhalation delivery has the unit of mg/L 6h/day (amount of drug in mg in 1L of air, for 6 hours per day). [8]
≡ 64.798 91 mg: grave: gv grave was the original name of the kilogram ≡ 1 kg hundredweight (long) long cwt or cwt ≡ 112 lb av = 50.802 345 44 kg: hundredweight (short); cental: sh cwt ≡ 100 lb av = 45.359 237 kg: hyl; metric slug: ≡ 1 kgf / 1 m/s 2 = 9.806 65 kg: kilogram (kilogramme) kg ≈ mass of the prototype near Paris ≈ mass ...