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High-pressure chemistry is concerned with those chemical processes that are carried out under high pressure – pressures in the thousands of bars (100 kPa) or higher.High-pressure processes are generally faster and have a higher conversion efficiency than processes at ambient pressure.
In science and engineering the study of high pressure examines its effects on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure. High pressure usually means pressures of thousands (kilo bars ) or millions (megabars) of times atmospheric pressure (about 1 bar or 100,000 Pa).
Pumps vary in pressure capacity, but their performance is measured on their ability to yield a consistent and reproducible volumetric flow rate. Pressure may reach as high as 60 MPa (6000 lbf/in 2), or about 600 atmospheres. Modern HPLC systems have been improved to work at much higher pressures, and therefore are able to use much smaller ...
The pressure referred to is the partial pressure of the substance, not the total (e.g. atmospheric) pressure of the entire system. Thus, any solid can sublime if its vapour pressure is higher than the surrounding partial pressure of the same substance, and in some cases, sublimation occurs at an appreciable rate (e.g. water ice just below 0 °C).
Pressure experiments are experiments performed at pressures lower or higher than atmospheric pressure, called low-pressure experiments and high-pressure experiments, respectively. Pressure experiment are necessary because substances behave differently at different pressures. For example, water boils at a lower temperature at lower pressures ...
An example is the Gibbs free energy (,), which is a function of pressure and temperature. Knowing any one thermodynamic potential F {\displaystyle {\mathcal {F}}} is sufficient to compute all equilibrium properties of a substance, often simply by taking derivatives of F {\displaystyle {\mathcal {F}}} . [ 55 ]
A high current electrical fault can create an "electrical explosion" by forming a high-energy electrical arc which rapidly vaporizes metal and insulation material. This arc flash hazard is a danger to people working on energized switchgear. Excessive magnetic pressure within an ultra-strong electromagnet can cause a magnetic explosion.
For example, IUPAC has, since 1982, defined standard reference conditions as being 0 °C and 100 kPa (1 bar), in contrast to its old standard of 0 °C and 101.325 kPa (1 atm). [2] The new value is the mean atmospheric pressure at an altitude of about 112 metres, which is closer to the worldwide median altitude of human habitation (194 m). [10]