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An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. [1] Physicists often discuss ideal test results that would occur in a perfect vacuum, which they sometimes simply call "vacuum" or free space , and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a ...
The ideal gas law can still be used to describe the behavior of a real gas if the pressure is replaced by a fugacity f, defined so that = and = That is, at low pressures f is the same as the pressure, so it has the same units as pressure.
For the expansion (or compression) of an ideal gas from an initial volume and pressure to a final volume and pressure at any constant temperature, the change in entropy is given by: = = Here is the amount of gas (in moles) and is the ideal gas constant.
Bearing pressure – a particular case of contact mechanics often occurring in cases where a convex surface (male cylinder or sphere) contacts a concave surface (female cylinder or sphere: bore or hemispherical cup). Excessive contact pressure can lead to a typical bearing failure such as a plastic deformation similar to peening.
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
The temperature at which a liquid undergoes a phase change into a gas; the vapour pressure of liquid and gas are equal at this temperature. boiling point elevation The phenomenon by which the boiling point of a liquid (a solvent) increases when another compound is added, meaning that the resulting solution has a higher boiling point than the ...
In thermodynamics, the reduced properties of a fluid are a set of state variables scaled by the fluid's state properties at its critical point.These dimensionless thermodynamic coordinates, taken together with a substance's compressibility factor, provide the basis for the simplest form of the theorem of corresponding states.
At a given temperature and pressure, repulsive forces tend to make the volume larger than for an ideal gas; when these forces dominate Z is greater than unity. When attractive forces dominate, Z is less than unity. The relative importance of attractive forces decreases as temperature increases (see effect on gases).