HAZMAT Technician Practice Exam

What is meant by self-accelerating decomposition temperature?

1. The temperature at which organic peroxides start to dissolve

2. The temperature at which irreversible decomposition begins in peroxides

3. The temperature at which hydrocarbons ignite spontaneously

4. The maximum temperature a substance can reach before vaporizing

The correct answer is: The temperature at which irreversible decomposition begins in peroxides

Self-accelerating decomposition temperature (SADT) refers specifically to the temperature at which a substance, particularly organic peroxides, begins to undergo irreversible chemical decomposition without any external intervention. This decomposition process creates a situation where the heat generated by the chemical reaction increases the temperature of the material, leading to a runaway reaction that can be hazardous. This concept is critical in hazmat handling and storage, as knowing the SADT helps in determining safe operating temperatures for substances that may decompose and pose risks. The other choices relate to different chemical behaviors and phenomena. For instance, the onset of spontaneous ignition in hydrocarbons is a different concept and is tied to their specific ignition points rather than decomposition rates. Similarly, the vaporization temperature pertains to the transition of a substance from liquid to gas and is not directly linked to chemical stability or decomposition. The dissolution of organic peroxides is also not the main focus of what SADT represents, as it emphasizes the heat and reaction dynamics associated with decomposition rather than solubility. Understanding SADT is essential for ensuring that materials are stored and handled under appropriate conditions to prevent dangerous reactions.