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Oxygen transmission rate (OTR) is the measurement of the amount of oxygen gas that passes through a substance over a given period. It is mostly carried out on non-porous materials, where the mode of transport is diffusion, but there are a growing number of applications where the transmission rate also depends on flow through apertures of some description.
The oxygen content of a stored gas mixture can be analysed by passing a small flow of the gas over a recently calibrated cell for long enough that the output stabilises. The stable output represents the fraction of oxygen in the mixture. Care must be taken to ensure that the gas flow is not diluted by ambient air, as this would affect the reading.
An air flow meter is a device similar to an anemometer that measures air flow, i.e. how much air is flowing through a tube. It does not measure the volume of the air passing through the tube, it measures the mass of air flowing through the device per unit time, though Thus air flow meters are simply an application of mass flow meters for the ...
[49] [50] Tennant, who had the advantage of a much greater amount of residue, continued his research and identified the two previously undiscovered elements in the black residue, iridium and osmium. [13] [22] He obtained dark red crystals (probably of Na 2 [IrCl 6]·n H 2 O) by a sequence of reactions with sodium hydroxide and hydrochloric acid ...
Osmium (from Ancient Greek ὀσμή (osmḗ) 'smell') is a chemical element; it has symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element.
Osmium(I) iodide is a metallic grey solid produced by the reaction of osmium tetroxide and hydroiodic acid heated in a water bath for 48 hours in a carbon dioxide atmosphere. It is an amorphous compound. [34] Osmium(II) iodide is a black solid [35] produced by the reaction of osmium tetroxide and hydroiodic acid at 250 °C in nitrogen: [34]
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Air sensitivity is a term used, particularly in chemistry, to denote the reactivity of chemical compounds with some constituent of air.Most often, reactions occur with atmospheric oxygen (O 2) or water vapor (H 2 O), [1] although reactions with the other constituents of air such as carbon monoxide (CO), carbon dioxide (CO 2), and nitrogen (N 2) are also possible.