Final answer:
Manganese dioxide can catalyze the decomposition of hydrogen peroxide into water and oxygen gas, a process that is a clear example of a chemical change.
Step-by-step explanation:
Substances that can undergo decomposition via a chemical change are numerous, and one specific example of such a substance is hydrogen peroxide (H₂O₂) when catalyzed by manganese dioxide (MnO₂). During this reaction, manganese dioxide acts as a catalyst that speeds up the decomposition of hydrogen peroxide into water (H₂O) and oxygen gas (O₂).
This is evidenced by the observation of gas bubbling up during the reaction. The ability of the manganese compound to catalyze this reaction is due to manganese's capability to exist in multiple oxidation states, which, in turn, allows it to participate in a variety of chemical reactions. In the case of permanganate ions (MnO₄⁻), manganese has an oxidation state of +7. It's important to note that while elemental manganese itself doesn't decompose, it can facilitate the decomposition of other substances in chemical reactions.