What does the term "sublimation" refer to in the context of hazardous materials?

• A. The transition from solid to liquid
• B. The transition from gas to solid
• C. The process of solid becoming gas without liquid phase
• D. The chemical bond formation

Answer: (C)

Sublimation is a process where a solid transforms directly into a gas without passing through the liquid phase. This phenomenon occurs at specific temperatures and pressures, typically when a compound's vapor pressure exceeds atmospheric pressure. In the context of hazardous materials, understanding sublimation is crucial because it can impact the behavior and transport of substances in the environment. For instance, certain chemicals may release toxic gases directly from solid forms under certain conditions, presenting unique hazards during emergencies or spills. This understanding aids emergency responders in assessing risk and implementing appropriate safety measures.

The other options describe different phase transitions that do not accurately define sublimation. The transition from solid to liquid refers to melting, while the transition from gas to solid is known as deposition. Chemical bond formation is a different concept related to reactions and molecular interactions, rather than a phase change.