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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. When working with aqueous solutions, it ...
1 atm = absolute pressure of 101.325 kPa or 1.01325 bar; mol = gram mole and kmol = 1000 gram moles; Pollution regulations in the United States typically reference their pollutant limits to an ambient temperature of 20 to 25 °C as noted above. In most other nations, the reference ambient temperature for pollutant limits may be 0 °C or other ...
Lethal dose. In toxicology, the lethal dose (LD) is an indication of the lethal toxicity of a given substance or type of radiation. Because resistance varies from one individual to another, the "lethal dose" represents a dose (usually recorded as dose per kilogram of subject body weight) at which a given percentage of subjects will die.
Wind speed conversion factors. Meteorological data includes wind speeds which may be expressed as statute miles per hour, knots, or meters per second. Here are the conversion factors for those various expressions of wind speed: 1 m/s = 2.237 statute mile/h = 1.944 knots. 1 knot = 1.151 statute mile/h = 0.514 m/s.
In environmental chemistry, the chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. It is commonly expressed in mass of oxygen consumed over volume of solution, which in SI units is milligrams per liter (mg / L). A COD test can be used to quickly quantify the ...
Median lethal dose. In toxicology, the median lethal dose, LD50 (abbreviation for " lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a given substance. [1] The value of LD 50 for a substance is the dose required to kill half the members of a tested population after a specified test ...
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. [1][2][3][4] The acid value measures the acidity of water-insoluble substances like oils, fats, waxes and resins, which do not have a pH value. The acid number is a measure of the ...
Acetic acid / ə ˈ s iː t ɪ k /, systematically named ethanoic acid / ˌ ɛ θ ə ˈ n oʊ ɪ k /, is an acidic, colourless liquid and organic compound with the chemical formula CH 3 COOH (also written as CH 3 CO 2 H, C 2 H 4 O 2, or HC 2 H 3 O 2).