Which of the following statements correctly describes the melting process?
A It is exothermic because heat is gained from the surroundings.
B It is endothermic because heat is lost to the surroundings.
C It is exothermic because heat is lost to the surroundings.
D It is endothermic because heat is gained from the surroundings.
The Correct Answer and Explanation is :
The correct answer is D: It is endothermic because heat is gained from the surroundings.
Explanation:
Melting is the process where a solid transforms into a liquid when heat is added. This transition occurs when the temperature of the solid reaches its melting point. During melting, the molecules of the solid absorb energy, which causes them to vibrate more rapidly and overcome the forces holding them in a fixed position. This energy absorption is critical, as it allows the solid structure to break down and transition into the liquid state.
Since melting requires energy input, it is classified as an endothermic process. In thermodynamic terms, “endothermic” refers to any process that absorbs heat from the surroundings. As the solid gains heat energy, the surroundings experience a slight decrease in temperature, which can often be felt if the process is occurring in an open environment. For instance, when ice melts, it absorbs heat from the surrounding air or any surface it is in contact with, resulting in a cooling effect on those surfaces.
Conversely, an exothermic process is one that releases heat into the surroundings, which is not the case for melting. Exothermic reactions are typically associated with processes like combustion or condensation, where the formation of bonds or structures releases energy.
In summary, melting is an endothermic process because it involves the absorption of heat from the surroundings to facilitate the transition of a solid to a liquid. Understanding this concept is crucial in fields such as chemistry and physics, as it explains not only the behavior of materials at different temperatures but also the energy dynamics involved in phase changes.