Daily Life Examples of Specific Latent Heat

Specific latent heat (L) is defined as the amount of thermal energy (heat, Q) that is absorbed or released when a body undergoes a constant-temperature process. The equation for specific latent heat is:

L = Q / m

where:

• L is the specific latent heat
• Q is the heat absorbed or released
• m is the mass of a substance

Common units for specific latent heat include joules per gram (J/g) and kilojoules per kilogram (kJ/kg).

Specific Latent Heat

• Specific latent heat is an intensive property of matter, maintaining a consistent value regardless of sample size or the location within a substance from which the sample is taken.
• Phase changes, like melting, freezing, vaporization, or condensation, represent the most prevalent forms of constant-temperature processes.
• The energy associated with these processes is termed “latent” because it remains concealed within the molecules until the actual phase change occurs.
• This energy is termed “specific” as it is measured in relation to energy per unit mass.
• Common units for specific latent heat include joules per gram (J/g) and kilojoules per kilogram (kJ/kg).

Types of Latent Heat Transfer

Type of Heat	Description	Daily Life Examples
Latent Heat of Fusion	The heat absorbed or released when matter undergoes a phase change from solid to liquid (melting) at a constant temperature.	Melting ice, freezing food, turning chocolate from a solid to liquid.
Latent Heat of Vaporization	The heat absorbed or released when matter undergoes a phase change from liquid to gas (vaporization) at a constant temperature.	Boiling water, steam burns, evaporation of sweat during exercise.
Sensible Heat	Heat transfer between matter and its surroundings that does not involve a phase change and occurs at varying temperatures. Can be “sensed” as a change in the object’s temperature.	Touching a hot cup of coffee, feeling the warmth of the sun, cooling down with a fan.

Examples

This is a table of specific latent heat (SLH) of fusion and vaporization for common materials.

Material	Phase Change	Latent Heat (J/g)
Water	Fusion (Melting)	334
Water	Vaporization (Boiling)	2260
Ice (at 0°C)	Fusion (Melting)	334
Steam (at 100°C)	Vaporization (Boiling)	2260
Chocolate (fat)	Fusion (Melting)	Approximately 50
Ethanol	Fusion (Melting)	~110
Ethanol	Vaporization (Boiling)	~840
Acetone	Fusion (Melting)	~120
Acetone	Vaporization (Boiling)	~510
Oxygen (O2)	Fusion (Sublimation)	0.444
Nitrogen (N2)	Fusion (Sublimation)	0.250
Carbon Dioxide (CO2)	Sublimation	~571