What is latent heat of vaporisation and latent heat of fusion?
The first is the amount of heat needed to vaporize a liquid or sublime a solid, per unit mass. (Sublimation occurs when a material goes directly from solid to vapor). Temperature remains constant while the phase change occurs.
The second, latent heat of fusuion, is the heat needed to melt a solid (at its melting point temperature), per unit mass.
The latent heat of vaporization and the latent heat of fusion are both terms used in thermodynamics to describe the amount of energy required to change the state of a substance from one form to another.
1. Latent heat of vaporization: This refers to the energy required to change a substance from its liquid state to its gaseous state at a constant temperature. In simpler terms, it is the amount of heat energy needed for a substance to evaporate or boil. This energy is used to overcome the intermolecular forces holding the liquid molecules together and allow them to escape into the gas phase. The latent heat of vaporization is typically expressed in units of joules per kilogram (J/kg) or calories per gram (cal/g).
To calculate the latent heat of vaporization, you would typically need to know the mass of the substance being vaporized and the energy absorbed during the phase change. The formula to calculate the latent heat of vaporization is:
Latent heat of vaporization = Energy absorbed during vaporization / Mass of the substance
2. Latent heat of fusion: This refers to the energy required to change a substance from its solid state to its liquid state, or vice versa, at a constant temperature. In simpler terms, it is the amount of heat energy needed for a substance to melt or freeze. This energy is used to break the intermolecular forces holding the solid particles together or to form these forces when freezing. The latent heat of fusion is also expressed in units of joules per kilogram (J/kg) or calories per gram (cal/g).
To calculate the latent heat of fusion, you would typically need to know the mass of the substance undergoing fusion and the energy absorbed or released during the phase change. The formula to calculate the latent heat of fusion is:
Latent heat of fusion = Energy absorbed or released during fusion / Mass of the substance
It is worth noting that the latent heat values are specific to each substance and can vary depending on the substance being considered.