heat of sublimation

Học thuật
Thân thiện
heat of sublimation

A chemist measures the heat of sublimation for dry ice in a laboratory.

Definition
  1. Noun:
    • The enthalpy change required for sublimation: The heat of sublimation is the amount of thermal energy absorbed per unit mass of a substance when it transitions directly from the solid phase to the gaseous phase (sublimation) at constant temperature and pressure.
Usage
  • The is a specific thermodynamic property used in physics and chemistry.
  • It is typically discussed in the context of phase changes, material science, and thermodynamic calculations.
  • It is a positive value, representing energy input into the system.
Examples
  • Noun:
    • The heat of sublimation for dry ice (solid carbon dioxide) is relatively low, which is why it sublimes so readily at room temperature.
    • To design an efficient freeze-drying process, engineers must know the heat of sublimation of water.
    • In the equation, the total energy required is the sum of the heat of fusion and the heat of vaporization, which is equivalent to the heat of sublimation.
Advanced Usage
  • "Molar heat of sublimation": The enthalpy change per mole of substance for sublimation.
    • The molar heat of sublimation is often denoted by ΔH_sub.
  • The is equal to the sum of the heat of fusion and the heat of vaporization for a given substance at the same temperature and pressure (ΔHfus + ΔH_vap).
Variants and Related Words
  • Sublimation (n): The physical process of a substance transitioning directly from a solid to a gas.
  • Enthalpy of sublimation (n): A more formal term synonymous with , emphasizing the thermodynamic state function.
  • Heat of fusion (n): The enthalpy change for the solid-to-liquid transition.
  • Heat of vaporization (n): The enthalpy change for the liquid-to-gas transition.
Synonyms
  • Enthalpy of sublimation: The precise thermodynamic equivalent.
  • Latent heat of sublimation: Emphasizes the "hidden" energy absorbed during the phase change without a temperature change.
Related Phrases
  • To sublime (v): To undergo the process of sublimation.
    • Iodine crystals sublime at room temperature, releasing a violet vapor.
  • Sublimation point (n): The temperature and pressure at which sublimation occurs for a given substance.
heat of sublimation

A chemist measures the heat of sublimation for dry ice in a laboratory.

Noun
  1. heat absorbed by a unit mass of material when it changes from a solid to a gaseous state