heat of vaporisation

Thân thiện

A pot of water boils on a stove, demonstrating the heat of vaporisation.

Definition

1. Noun:
   • The enthalpy change required to transform a given quantity of a substance from a liquid into a gas at its boiling point under constant pressure. It is the amount of heat energy absorbed per unit mass when a substance changes from the liquid phase to the vapor phase without a change in temperature.

Usage

• This term is used in scientific contexts, particularly in physics, chemistry, and engineering, to describe a specific thermodynamic property of a substance.
• It is a quantitative measure. You typically state the heat of vaporization a specific substance.
• It is also known as the enthalpy of vaporization.

Examples

• Scientific Explanation:
  • The heat of vaporization of water is high, which is why sweating is an effective cooling mechanism for the human body.
  • When designing a refrigeration system, engineers must consider the heat of vaporization of the refrigerant.
  • In the experiment, we calculated the heat of vaporization of ethanol by measuring the energy needed to boil a known mass.

Advanced Usage

• Molar Heat of Vaporization: The heat of vaporization expressed per mole of substance (units: J/mol or kJ/mol), rather than per unit mass (units: J/g or kJ/kg).
  • The molar heat of vaporization is a more fundamental property for chemical calculations.

Variants and Related Words

• Enthalpy of vaporization (n): A synonym for heat of vaporization, using the more precise thermodynamic term "enthalpy."
• Latent heat of vaporization (n): An older but still common term emphasizing that this heat energy is "hidden" as it does not cause a temperature change.
• Heat of condensation (n): The equivalent amount of heat released when a gas condenses into a liquid at its boiling point. It is numerically equal to the heat of vaporization but opposite in sign (exothermic).

Synonyms

• Enthalpy of vaporization
• Latent heat of vaporization

Related Scientific Concepts

• Phase change: The physical process (liquid to gas) during which the heat of vaporization is absorbed.
• Boiling point: The temperature at which vaporization occurs throughout the liquid, and where the heat of vaporization is measured.
• Specific heat capacity: A different property measuring the heat required to change a substance's , not its phase.

Học thuật

Noun

1. heat absorbed by a unit mass of a material at its boiling point in order to convert the material into a gas at the same temperature

Từ đồng nghĩa

• heat of vaporization