critical pressure

chemistry

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June 25, 2026

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The critical pressure is the pressure exerted by a substance when it reaches its critical state. This critical state occurs at the critical point, which is defined by specific conditions of critical temperature, critical pressure, and critical density. At the critical point, a liquid and its vapor become indistinguishable, meaning the boundary between the two phases disappears because their densities become equal. This phenomenon is visualized on a phase diagram, which maps the different states of a substance under varying pressure and temperature.1234

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water
Water at high temperatures and pressures
…beyond its critical temperature and pressure (374 °C [705.2 °F], 218 atmospheres). Above its critical temperature, the distinction between the liquid and gaseous states of water disappears—it becomes a supercritical fluid, the density of which can be varied from liquidlike to gaslike by varying its temperature and pressure. If the…
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…beyond its critical temperature and pressure (374 °C [705.2 °F], 218 atmospheres). Above its critical temperature, the distinction between the liquid and gaseous states of water disappears—it becomes a supercritical fluid, the density of which can be varied from liquidlike to gaslike by varying its temperature and pressure. If the…
Read More