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inhaled osmium tetroxide is immediately dangerous to life or health (1 mg Os/m 3) [13] 10 −8: 10 −7: 101 nM: hydronium and hydroxide ions in pure water at 25 °C (pK W = 13.99) [14] 10 −6: μM: 10 −5: 10 −4: 180–480 μM: normal range for uric acid in blood [10] 570 μM: inhaled carbon monoxide induces unconsciousness in 2–3 ...
It was originally defined as "the quantity or mass of radium emanation in equilibrium with one gram of radium (element)", [1] but is currently defined as 1 Ci = 3.7 × 10 10 decays per second [4] after more accurate measurements of the activity of 226 Ra (which has a specific activity of 3.66 × 10 10 Bq/g [5]).
The name "katal" has been used for decades. The first proposal to make it an SI unit came in 1978, [4] [8] and it became an official SI unit in 1999. [4] [9] [10] The name comes from the Ancient Greek κατάλυσις (katalysis), meaning "dissolution"; [11] the word "catalysis" itself is a Latinized form of the Greek word. [11] [12]
[1] [2] It is usually given in units of becquerel per kilogram (Bq/kg), but another commonly used unit of specific activity is the curie per gram (Ci/g). In the context of radioactivity , activity or total activity (symbol A ) is a physical quantity defined as the number of radioactive transformations per second that occur in a particular ...
Conversion of units is the conversion of the unit of measurement in which a quantity is expressed, typically through a multiplicative conversion factor that changes the unit without changing the quantity. This is also often loosely taken to include replacement of a quantity with a corresponding quantity that describes the same physical property.
For example, the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb is about 4.7 for the greenhouse gas CFC-11 in air (Molar mass of CFC-11 / Mean molar mass of air = 137.368 / 28.97 = 4.74). For volume fraction, the suffix "V" or "v" is sometimes appended to the parts-per notation (e.g. ppmV, ppbv, pptv).
Historically, the mole was defined as the amount of substance in 12 grams of the carbon-12 isotope.As a consequence, the mass of one mole of a chemical compound, in grams, is numerically equal (for all practical purposes) to the mass of one molecule or formula unit of the compound, in daltons, and the molar mass of an isotope in grams per mole is approximately equal to the mass number ...
Normality is defined as the number of gram or mole equivalents of solute present in one liter of solution.The SI unit of normality is equivalents per liter (Eq/L). = where N is normality, m sol is the mass of solute in grams, EW sol is the equivalent weight of solute, and V soln is the volume of the entire solution in liters.