Meltingboiling

Meltingboiling is a colloquial term used to describe the processes of melting and boiling, two distinct phase transitions that substances undergo. Melting, also known as fusion, is the process where a solid changes into a liquid state. This occurs when a substance absorbs enough thermal energy to overcome the intermolecular forces holding its particles in a fixed, rigid structure. The temperature at which melting occurs for a pure substance at standard atmospheric pressure is called its melting point.

Boiling, on the other hand, is the process where a liquid changes into a gas or vapor. This happens when the vapor pressure of the liquid equals the ambient pressure, allowing bubbles of vapor to form within the liquid and rise to the surface. The temperature at which boiling occurs is known as the boiling point. Like the melting point, the boiling point of a pure substance at standard atmospheric pressure is a characteristic property.

While distinct, both melting and boiling are endothermic processes, meaning they require an input of energy, typically in the form of heat. The energy absorbed during these phase changes is used to break intermolecular bonds, rather than to increase the kinetic energy of the particles (which would result in a temperature increase). For example, water melts at 0 degrees Celsius and boils at 100 degrees Celsius at standard atmospheric pressure. Understanding these transitions is fundamental in chemistry and physics for describing the behavior of matter.