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The heat content of an ideal gas is independent of pressure (or volume), but the heat content of real gases varies with pressure, hence the need to define the state for the gas (real or ideal) and the pressure. Note that for some thermodynamic databases such as for steam, the reference temperature is 273.15 K (0 °C).
Menthol has local anesthetic and counterirritant qualities, and it is widely used to relieve minor throat irritation. Menthol has been demonstrated to cause a subjective nasal decongestant effect without any objective decongestant action, and administration of menthol via a nasal inhaler in humans has also been shown to cause nasal congestion ...
where the H 2 O byproduct is recycled via the water-gas shift reaction. CO + H 2 O → CO 2 + H 2. This gives an overall reaction CO + 2 H 2 → CH 3 OH. which is the same as listed above. In a process closely related to methanol production from synthesis gas, a feed of hydrogen and CO 2 can be used directly. [55]
Ammonium nitrite on heating yields nitrogen gas and water. Barium azide-"Ba(N 3)"on heating yields barium metal and nitrogen gas. Sodium azide on heating at 300 °C (573 K; 572 °F) violently decomposes to nitrogen and metallic sodium. Sodium nitrate on heating yields sodium nitrite and oxygen gas.
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 kPa.
The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in the literature, the most recent reference [Handbook on the chemistry and physics of rare earths, vol.12 (1989)] is given with 1529 °C.
For example, the entropies of vaporization of water, ethanol, formic acid and hydrogen fluoride are far from the predicted values. The entropy of vaporization of XeF 6 at its boiling point has the extraordinarily high value of 136.9 J/(K·mol) or 16.5 R. [ 4 ] The characteristic of those liquids to which Trouton’s rule cannot be applied is ...