Which heat transition involves converting a solid directly into a vapor?

The process of converting a solid directly into a vapor is termed sublimation. During sublimation, a substance transitions from a solid phase to a gaseous phase without going through the liquid phase. This occurs when molecules in the solid gain enough energy to break free from the solid structure and disperse into the air as vapor.

In this context, latent heat is the energy absorbed or released during the phase change. Specifically, in sublimation, the latent heat being absorbed is known as the latent heat of sublimation. This is essential for understanding thermodynamic behaviors in various applications, including refrigeration and air conditioning systems, where managing phase changes is critical for efficiency.

Understanding sublimation helps clarify why other choices do not fit; latent heat of melting and latent heat of fusion are associated with the solid to liquid transition, whereas latent heat of vaporization pertains to liquid to gas transitions. Thus, amongst the options provided, sublimation is uniquely characterized by the direct conversion from solid to vapor.