Yes, burning paper is indeed a chemical reaction. When paper burns, it undergoes a process called combustion, which is a chemical reaction between the paper (primarily composed of cellulose) and oxygen in the air.
During this process, the cellulose in the paper breaks down and reacts with oxygen, producing heat, light, carbon dioxide, and water vapor as byproducts. The paper itself changes its chemical structure and is transformed into different substances, which signifies that a chemical reaction has occurred.
Additionally, the heat released during combustion can even lead to the ignition of other materials nearby, illustrating how chemical reactions can release energy. Thus, the burning of paper is a classic example of a chemical change rather than a physical change.