What is it called when matter undergoes a transformation and creates new substances?

The process described is known as a chemical change. This occurs when matter transforms in such a way that new substances are formed, which have different properties from the original material. Chemical changes often involve chemical reactions, such as combustion, oxidation, or decomposition, and can be observed through changes in color, temperature, gas production, or the formation of a precipitate.

In contrast to chemical changes, physical changes affect the form of a substance but do not alter its chemical composition. For example, freezing or melting water only changes its state but not its chemical identity as H2O.

Nuclear change pertains to transformations that occur in the nuclei of atoms, such as radioactivity, which can lead to the formation of different elements but does not directly relate to the typical transformations we observe in chemical reactions.

A phase change refers specifically to transitions between different states of matter, like solid to liquid or liquid to gas. These changes do not create new substances; they simply alter the physical state of existing substances.

Thus, when a transformation leads to the formation of entirely new substances, categorizing it as a chemical change is accurate and highlights the fundamental nature of the process.