Question

which of these is an example of a physical change?
o sugar, when heated, producing carbon dioxide and water
o solid ice, when heated, turning into liquid water
o sodium, when exposed to chlorine, forming sodium chloride
o aluminum, when heated in air, forming aluminum oxide

Explanation:

A physical change is a change in which the substance's chemical composition remains the same. When solid ice turns into liquid water upon heating, only the state of water changes from solid to liquid, and its chemical formula ($H_2O$) remains unchanged. In the other options, new substances are formed through chemical reactions, which are chemical changes.

Answer:

solid ice, when heated, turning into liquid water