<em>A process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in</em><u><em>physical form or a nuclear reaction.</em></u>
Explanation:
A process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in <u><em>physical form or a nuclear reaction.</em></u>
<em>A chemical reaction is a process in which one or more substances, also called reactants, are converted to one or more different substances, known as products. ... If a physical change occurs, the physical properties of a substance will change, but its chemical identity will remain the same.</em>