Tiivistyskäyrällä

Tiivistyskäyrällä, which translates to "condensation curve" or "saturation curve" in English, is a graphical representation used in thermodynamics and physical chemistry to illustrate the relationship between pressure and temperature at which a substance exists in equilibrium between its liquid and gaseous phases. Specifically, it depicts the conditions where boiling and condensation occur simultaneously.

On a typical pressure-temperature (P-T) diagram, the tiivistyskäyrällä separates the liquid phase region from the gaseous phase region. To the left of the curve, the substance is in a liquid state, while to the right, it exists as a gas. Any point lying directly on the tiivistyskäyrällä represents a state where both liquid and gas can coexist in thermal equilibrium.

The shape and position of the tiivistyskäyrällä are unique to each substance. For most substances, as temperature increases, the pressure at which condensation occurs also increases. This is because higher temperatures provide more kinetic energy to the molecules, requiring higher external pressure to keep them in the liquid state. The curve terminates at the critical point, beyond which the distinction between liquid and gas phases disappears. Understanding the tiivistyskäyrällä is crucial for processes involving phase changes, such as distillation, evaporation, and refrigeration.