When wood burns do new substances form?

Yes, when wood burns, it undergoes a chemical reaction called combustion, resulting in the formation of new substances. The primary products of this reaction are carbon dioxide, water vapor, and various gases, along with solid residues like ash. The original compounds in wood, primarily cellulose, lignin, and hemicellulose, break down and transform into these new substances as they react with oxygen. Thus, the burning of wood leads to significant chemical changes and the creation of new materials.