HAZMAT Technician Practice Exam

A characteristic of a chemical change is that a new substance is produced. During a chemical change, the original substances undergo a transformation that alters their chemical structure, resulting in the formation of one or more new substances with different properties. This is the fundamental aspect that distinguishes chemical changes from physical changes, where the original substances remain unchanged at the molecular level. For example, when iron rusts, the iron combines with oxygen in the presence of moisture to form iron oxide, a completely different compound, signifying that a chemical change has occurred. In contrast, the other traits mentioned, such as a lack of new substance formation or changes limited to physical properties, do not pertain to chemical changes, which is why they are not correct in this context.