Latent Heat of Fusion

The latent heat of fusion refers to the amount of heat energy required to convert a substance from a solid state to a liquid state at its melting point, without changing its temperature. It is also known as the heat of fusion or enthalpy of fusion. This concept is based on the principle that during the phase change from solid to liquid, the energy supplied is used to overcome the intermolecular forces between the particles of the substance, rather than increasing the temperature.

Explanation

When a substance undergoes fusion, its intermolecular forces weaken, allowing the particles to move more freely, resulting in a change from a solid to a liquid state. However, this process requires energy. The amount of energy required depends on the substance and is characterized by its latent heat of fusion.

Units of Measurement

The latent heat of fusion is typically measured in joules per gram (J/g) or calories per gram (cal/g). It represents the amount of energy needed to convert one gram of a substance from solid to liquid at its melting point.

Significance

The latent heat of fusion has several practical implications. For example:

1. Freezing and Melting: The latent heat of fusion plays a crucial role in the freezing and melting processes. When a substance freezes, it releases the same amount of energy it absorbed during melting.

2. Heat Storage and Transfer: The high latent heat of fusion of certain substances makes them effective heat storage and transfer mediums. For instance, water has a relatively high latent heat of fusion, which allows it to absorb and release large amounts of energy without experiencing drastic temperature changes. This property contributes to the Earth's climate regulation, as it helps to moderate temperature variations in bodies of water.

3. Industrial Applications: Knowledge of the latent heat of fusion is essential in various industrial processes. For instance, in refrigeration and air conditioning systems, it is utilized to remove heat from a substance by exploiting the latent heat released during its phase change.

In summary, the latent heat of fusion represents the energy required to convert a substance from a solid to a liquid state at its melting point. It has practical implications in various fields, such as heat storage, climate regulation, and industrial processes.

the heat energy required to covert 1 kg of solid into liquid at an constant atmospheric pressure is known as latent heat of fusion.