Question

A substance undergoes a change. Which of the following indicates that the change was a chemical change? The substance changed shape. New molecules formed. The substance froze. The substance changed size.

Answer 1

Answer: New molecules formed.

Explanation:

A physical change is defined as the change in which shape, size will be altered. No new substance gets formed in these reactions.

A chemical change is defined as the change in which chemical composition is altered. A new substance is formed in these reactions.

The substance changed shape is a physical change.

The substance froze means the state is changed and is a physical change.

The substance changed size is a physical change.

Thus when new molecules are formed, it is a chemical change.

Answer 2

In order to form new molecules, a chemical reaction would have to occur which means the change would be a chemical change.