Final answer:
The energy released by burning wood is explained by the concept of exothermic reactions, where more energy is emitted from forming strong new bonds between oxygen and wood molecules than is consumed in breaking the wood's chemical bonds.
Step-by-step explanation:
The observation that energy is required to break chemical bonds, and energy is released when bonds form helps us to understand the energy released by burning wood through the concept of exothermic reactions. When wood burns, the chemical bonds of cellulose and other compounds within the wood are broken, requiring energy. However, the bonds between the oxygen in the air and the carbon and hydrogen in the wood molecules are much stronger than the bonds in the wood itself. As these new bonds form, more energy is released than was consumed to break the original bonds, resulting in an overall release of energy as heat and light.
This process of bond breaking and formation can be understood in terms of bond enthalpies or bond dissociation energy. To start a fire, some energy input is needed to initiate the reaction (e.g., a match or lighter), but once the reaction begins, it becomes self-sustaining as it releases energy. This release of energy is due to the formation of new bonds during the combustion process which are stronger than the bonds that were broken in the wood's molecules, making the reaction exothermic.