Critical point
Definition
The critical point is the temperature and pressure at which the liquid and gas phases of a substance become indistinguishable. At this point, the properties of the liquid and gas phases converge into a single phase called a supercritical fluid.
5 Must Know Facts For Your Next Test
- At the critical point, the density of the liquid phase equals the density of the gas phase.
- The critical temperature is the highest temperature at which a substance can exist as a liquid, regardless of pressure.
- Critical pressure is the minimum pressure required to liquefy a substance at its critical temperature.
- Supercritical fluids have unique properties that are different from both liquids and gases.
- Water's critical point occurs at approximately 374°C and 22.1 MPa.
Review Questions
- What happens to the properties of a substance at its critical point?
- Why is it impossible to distinguish between liquid and gas phases beyond the critical point?
- What are supercritical fluids, and how do they differ from ordinary liquids and gases?
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Related terms
Phase Diagram: A graphical representation showing the different states of matter (solid, liquid, gas) of a substance as a function of temperature and pressure.
Triple Point: The specific temperature and pressure where all three phases (solid, liquid, gas) coexist in equilibrium.
Latent Heat: \(\text{The amount of heat absorbed or released during a phase change without changing temperature.}\)
