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Chemistry LibreTexts

Phase Transitions

  • Page ID
    • Boiling
      Boiling is the process by which a liquid turns into a vapor when it is heated to its boiling point. The change from a liquid phase to a gaseous phase occurs when the vapor pressure of the liquid is equal to the atmospheric pressure exerted on the liquid. Boiling is a physical change and molecules are not chemically altered during the process.
    • Clausius-Clapeyron Equation
      The Clausius-Clapeyron equation allows us to estimate the vapor pressure at another temperature, if the vapor pressure is known at some temperature, and if the enthalpy of vaporization is known.
    • Fundamentals of Phase Transitions
      Phase transition is when a substance changes from a solid, liquid, or gas state to a different state. Every element and substance can transition from one phase to another at a specific combination of temperature and pressure.
    • Phase Diagrams
      Phase diagram is a graphical representation of the physical states of a substance under different conditions of temperature and pressure. A typical phase diagram has pressure on the y-axis and temperature on the x-axis. As we cross the lines or curves on the phase diagram, a phase change occurs. In addition, two states of the substance coexist in equilibrium on the lines or curves.
    • Simple Kinetic Theory
      This page takes a simple look at solids, liquids and gases, and changes of state such as melting and boiling, in terms of the behavior of the particles present.
    • Vapor Pressure
      This page looks at how the equilibrium between a liquid (or a solid) and its vapor leads to the idea of a saturated vapor pressure. It also looks at how saturated vapor pressure varies with temperature, and the relationship between saturated vapor pressure and boiling point.

    Thumbnail: Structural details of melting icicles against gray sky. (CC SA-BY 3.0; Wing-Chi Poon).