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Argon. face-centered cubic (fcc) ( cF4) Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. [ 9] Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv ). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but ...
Paschen's law is an equation that gives the breakdown voltage, that is, the voltage necessary to start a discharge or electric arc, between two electrodes in a gas as a function of pressure and gap length. [ 2][ 3] It is named after Friedrich Paschen who discovered it empirically in 1889. [ 4]
The atmospheric pressure is roughly equal to the sum of partial pressures of constituent gases – oxygen, nitrogen, argon, water vapor, carbon dioxide, etc.. In a mixture of gases, each constituent gas has a partial pressure which is the notional pressure of that constituent gas as if it alone occupied the entire volume of the original mixture at the same temperature. [1]
Values are given in terms of temperature necessary to reach the specified pressure. Valid results within the quoted ranges from most equations are included in the table for comparison. A conversion factor is included into the original first coefficients of the equations to provide the pressure in pascals (CR2: 5.006, SMI: -0.875).
In thermodynamics, a critical point (or critical state) is the end point of a phase equilibrium curve. One example is the liquid–vapor critical point, the end point of the pressure–temperature curve that designates conditions under which a liquid and its vapor can coexist. At higher temperatures, the gas comes into a supercritical phase ...
CRC Press. Boca Raton, Florida, 2003; Section 6, Fluid Properties; Critical Constants. Also agrees with Celsius values from Section 4: Properties of the Elements and Inorganic Compounds, Melting, Boiling, Triple, and Critical Point Temperatures of the Elements. Estimated accuracy for T c and P c is indicated by the number of digits.
This molecule may occur in the upper atmosphere. Experimentally the molecule is made from a low-pressure argon gas with 0.1% carbon dioxide, irradiated by a 150 V electron beam. Argon is ionized, and can transfer the charge to a carbon dioxide molecule. [35] The dissociation energy of ArCO + 2 is 0.26 eV. [35] ArCO + 2 + CO 2 → Ar + CO 2 ·CO +
For instance, argon, krypton, and xenon form clathrates with hydroquinone, but helium and neon do not because they are too small or insufficiently polarizable to be retained. [61] Neon, argon, krypton, and xenon also form clathrate hydrates, where the noble gas is trapped in ice. [62] An endohedral fullerene compound containing a noble gas atom