False. When a substance burns, matter is not destroyed. It is simply transformed into different forms.

Here's why:

* Law of Conservation of Mass: This fundamental law states that matter cannot be created or destroyed, only transformed from one form to another.

* Burning as Chemical Reaction: Burning is a chemical reaction where the substance combines with oxygen (combustion). This reaction produces new substances like ash, smoke, and gases (like carbon dioxide).

* Mass Remains Constant: The total mass of the reactants (the substance burning and oxygen) before the reaction is equal to the total mass of the products (ash, smoke, and gases) after the reaction.

Therefore, the mass of the original substance is simply rearranged into different substances.