There are several different indicators that a chemical change has taken place.

Question

Which of the following examples would be considered an indicator that a chemical reaction has taken place? (1 point)
• The shape of paper changes as it is cut
• A liquid freezes
• Heat is given off after mixing two substances
• A Substance has dissolved

Answer 1

The example that would be considered an indicator that a chemical reaction has taken place is:

• Heat is given off after mixing two substances

This indicates that a chemical change has occurred, as it often involves the release of energy during a reaction. The other options—changing shape, freezing, and dissolving—are typically physical changes rather than chemical changes.