When one substance changes into one or more new substances, it has exhibited a 1. chemical change. 2. chemical reaction. 3. physical change. 4. chemical property?

The answer is 1. chemical change.

That is when one substance changes into one or more new substances, it has exhibited a chemical change.

A Chemical change is a change that takes places when a substance changes its composition by forming one or more new substances. As here also, one substance is changing into one or more new substance, thus it exhibits a chemical change.

Answer: Option (1) is the correct answer.

Explanation:

Chemical changes are defined as the changes which tend to show difference in chemical composition of a substance.

For example, toxicity, reactivity, combustion etc are all chemical changes.

In a chemical change, there will always be formation of a new compound.

On the other hand, a change which is unable to bring any difference in chemical composition of a substance is known as a physical change.

For example, a change in shape, size, mass, volume etc are all physical changes.

Thus, we can conclude that when one substance changes into one or more new substances, it has exhibited a chemical change.