* New substances are formed: When paper burns, it reacts with oxygen in the air. This reaction produces ash, carbon dioxide, water vapor, and other gases. These are completely different substances from the original paper.

* Irreversible: You can't easily turn the ash, carbon dioxide, and water vapor back into paper. The change is permanent.

* Energy is released: Burning paper releases heat and light, indicating a chemical reaction is taking place.

While the paper changes its physical appearance (it turns to ash), the fundamental chemical composition of the paper is altered, making it a chemical change.