Which term best describes a change in which a substance's identity remains the same?

Which term best describes a change in which a substance's identity remains the same?

• A. Chemical Change
• B. Physical Change
• C. Molecule
• D. Atom

Answer: (B)

The key idea is distinguishing changes by whether the substance’s identity is altered. A physical change is when matter changes form or appearance but keeps its original identity—its chemical composition stays the same. For example, ice turning to water changes state, but it’s still H2O. A substance can be cut, bent, melted, or dissolved, and these are physical changes because no new substance is formed. That’s why the term that fits is physical change. In a chemical change, the substance would transform into something with a different composition and properties (like iron rusting into iron oxide). The other options aren’t about changes in identity: a molecule or an atom are particles, not descriptions of the kind of change.

The key idea is distinguishing changes by whether the substance’s identity is altered. A physical change is when matter changes form or appearance but keeps its original identity—its chemical composition stays the same. For example, ice turning to water changes state, but it’s still H2O. A substance can be cut, bent, melted, or dissolved, and these are physical changes because no new substance is formed.

That’s why the term that fits is physical change. In a chemical change, the substance would transform into something with a different composition and properties (like iron rusting into iron oxide). The other options aren’t about changes in identity: a molecule or an atom are particles, not descriptions of the kind of change.