Which type of process involves the absorption of heat when a substance dissolves?

The absorption of heat during the dissolution of a substance is characteristic of an endothermic process. In this scenario, when a solute dissolves in a solvent, energy is absorbed from the surroundings to break the solute-solute and solvent-solvent interactions. This energy requirement can lead to a temperature decrease in the surrounding solution, as heat is drawn from the environment to facilitate the dissolution.

In contrast, exothermic processes release heat, which is not the behavior observed during the dissolution of certain solutes. Isothermal processes involve constant temperature conditions, where heat exchange occurs without a change in temperature, but they do not specifically highlight the heat absorption during dissolution. Combustion refers to chemical reactions that produce energy in the form of heat and typically involves the rapid combination of a substance with oxygen, markedly different from the dissolution process.

Thus, recognizing that the dissolution of certain substances involves heat absorption clearly identifies it as an endothermic process.