Which is an example of a physical change?

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Multiple Choice

Which is an example of a physical change?

Physical changes are changes in state or form that do not alter the substance's chemical identity. Melting fits this idea: when a solid absorbs heat and becomes a liquid, the material remains the same substance at the molecular level—the same molecules are present, just arranged in a fluid phase. No new substances are formed, and the change is typically reversible by cooling. The other examples involve chemical changes: burning transforms material into new compounds like carbon dioxide and water; digestion uses enzymes to break down molecules into different chemicals; rusting forms iron oxide, a new substance. So melting is the example that shows a physical change.

Physical changes are changes in state or form that do not alter the substance's chemical identity. Melting fits this idea: when a solid absorbs heat and becomes a liquid, the material remains the same substance at the molecular level—the same molecules are present, just arranged in a fluid phase. No new substances are formed, and the change is typically reversible by cooling. The other examples involve chemical changes: burning transforms material into new compounds like carbon dioxide and water; digestion uses enzymes to break down molecules into different chemicals; rusting forms iron oxide, a new substance. So melting is the example that shows a physical change.

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