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.

Noun

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