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Solid carbon dioxide sublimes rapidly along the solid-gas boundary (sublimation point) below the triple point (e.g., at the temperature of −78.5 °C, at atmospheric pressure), whereas its melting into liquid CO 2 can occur along the solid-liquid boundary (melting point) at pressures and temperatures above the triple point (i.e., 5.1 atm, − ...
A small piece of rapidly melting solid argon shows two concurrent phase changes. The transition from solid to liquid, and gas to liquid (shown by the white condensed water vapour). Other phase changes include: Transition to a mesophase between solid and liquid, such as one of the "liquid crystal" phases.
A vapor can exist in equilibrium with a liquid (or solid), in which case the gas pressure equals the vapor pressure of the liquid (or solid). A supercritical fluid (SCF) is a gas whose temperature and pressure are above the critical temperature and critical pressure respectively. In this state, the distinction between liquid and gas disappears.
Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO 2 does not have a liquid state at normal atmospheric pressure and sublimes directly from the solid state to the gas state. It is used primarily as a cooling agent, but is also used in fog machines at theatres for dramatic effects.
For deposition to occur, thermal energy must be removed from a gas. When the air becomes cold enough, water vapour in the air surrounding a leaf loses enough thermal energy to change into a solid. Even though the air temperature may be below the dew point, the water vapour in the air alone may not condense spontaneously. This supercooled water ...
Heat transfer is the energy exchanged between materials (solid/liquid/gas) as a result of a temperature difference. The thermodynamic free energy is the amount of work that a thermodynamic system can perform.
In thermodynamics, the enthalpy of sublimation, or heat of sublimation, is the heat required to sublimate (change from solid to gas) one mole of a substance at a given combination of temperature and pressure, usually standard temperature and pressure (STP). It is equal to the cohesive energy of the solid.
A similar concept applies to liquid–gas phase changes. [7] Water is an exception which has a solid-liquid boundary with negative slope so that the melting point decreases with pressure. This occurs because ice (solid water) is less dense than liquid water, as shown by the fact that ice floats on water.