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The boiling point cannot be reduced below the triple point. Suppose the heat of vaporization and the vapor pressure of a liquid at a certain temperature are known. In that case, the boiling point can be calculated by using the Clausius–Clapeyron equation, thus: where: is the boiling point at the pressure of interest, is the ideal gas constant ...
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 .
Once two of the three reduced properties are found, the compressibility chart can be used. In a compressibility chart, reduced pressure is on the x-axis and Z is on the y-axis. When given the reduced pressure and temperature, find the given pressure on the x-axis. From there, move up on the chart until the given reduced temperature is found.
The correct result would be P = 101.325 kPa, the normal (atmospheric) pressure. The deviation is −1.63 kPa or −1.61 %. It is important to use the same absolute units for T and T c as well as for P and P c. The unit system used (K or R for T) is irrelevant because of the usage of the reduced values T r and P r.
This technique is used when the boiling point of the desired compound is difficult to achieve or will cause the compound to decompose. [1] Reduced pressures decrease the boiling point of compounds. The reduction in boiling point can be calculated using a temperature-pressure nomograph using the Clausius–Clapeyron relation. [2]
The water is heated and then routed into a reduced-pressure flash evaporation "stage" where some of the water flashes into steam. This steam is subsequently condensed into salt-free water. The residual salty liquid from that first stage is introduced into a second flash evaporation stage at a pressure lower than the first stage pressure.
At the normal boiling point of a liquid, the vapor pressure is equal to the standard atmospheric pressure defined as 1 atmosphere, [1] 760 Torr, 101.325 kPa, or 14.69595 psi. For example, at any given temperature, methyl chloride has the highest vapor pressure of any of the liquids in the chart.
The temperature at standard pressure should be equal to the normal boiling point, but due to the considerable spread does not necessarily have to match values reported elsewhere. log refers to log base 10 (T/K) refers to temperature in Kelvin (K) (P/Pa) refers to pressure in Pascal (Pa)