Question

If a substance is heated and then cooled off but remains as the original substance a _____ change has occurred.

A) physical
B) chemical
C) structural
D) physical and chemical

Answer 1

I'm not a physicist, or an expert, but physical and structural both have a similar meaning, they both relate to appearances, but the question says "but remains as the original substance" so, if it isn't a visible change, then the only good answer left is a chemical change, hope this helps

Answer 2

I'm going to say physical change

explanation:

The substance as you said did not change therefore a chemical change could not have happened because they result in a new substance meaning one or multiple new substances could have been created from the chemical change. With a physical change the only thing that changes is the outward appearance.

example of physical change: water changing into ice. The frozen water is composed of the same elements as the liquid water.

Hopefully this helped and good luck.