Explain the process of melting and latent heat of fusion.

Process of Melting:
Melting is the process in which a solid turns into a liquid due to the absorption of heat. During this process, the temperature of the substance remains constant, and the heat energy supplied is used to overcome the forces that hold the particles together in the solid state.
Key Points of the Melting Process:
• Temperature: During the melting process, the temperature of the substance remains constant at the melting point. The melting point is the temperature at which the solid and liquid phases coexist in equilibrium.
• Energy Absorption: As heat is applied, the particles of the solid gain kinetic energy and begin to vibrate more vigorously. At the melting point, the particles acquire enough energy to break free from the fixed positions in the solid and move freely, thus turning into a liquid.
• Phase Change: The substance changes its phase from solid to liquid, but its temperature does not increase. This is because the heat energy is used to break the bonds between particles, not to increase their kinetic energy.
Latent Heat of Fusion:
The latent heat of fusion is the amount of heat required to change a unit mass of a substance from solid to liquid at constant temperature (at its melting point). During the phase change from solid to liquid, the temperature of the substance does not change, but the heat energy supplied is used to overcome the intermolecular forces that hold the solid particles together.
Formula for Latent Heat of Fusion: The latent heat of fusion LfL_f is given by the formula:
Q=m⋅LfQ = m \cdot L_f
Where:
• QQ is the amount of heat required (in joules or calories),
• mm is the mass of the substance (in kg or g),
• LfL_f is the latent heat of fusion (in joules per kg or calories per gram).
Example: If we have a substance with a mass of 100 grams and its latent heat of fusion is Lf=334 J/gL_f = 334 \, \text{J/g}, the amount of heat required to melt it is:
Q=100×334=33,400 JQ = 100 \times 334 = 33,400 \, \text{J}
Characteristics of Latent Heat of Fusion:
• It is specific to each material and depends on the substance being melted.
• During melting, the temperature remains constant as long as the substance is at its melting point.
• The latent heat of fusion can be measured experimentally by heating a solid at its melting point and measuring the amount of heat absorbed by the substance as it changes from solid to liquid.
In summary, melting is the process of changing a solid to a liquid by adding heat, and the heat energy required for this phase change is quantified as the latent heat of fusion.