Final answer:
The total mass of a sealed room and its contents remains unchanged after firewood burns, in accordance with the Law of Conservation of Mass. The mass of gases produced balances the mass of the consumed firewood and oxygen.
Step-by-step explanation:
When a pile of firewood burns in a sealed room, the total mass of the room and its contents remains the same before and after the fire. This is due to the Law of Conservation of Mass, which states that matter is neither created nor destroyed in a chemical reaction. The burning of wood in the presence of oxygen is a chemical reaction where the wood breaks down into ashes, carbon dioxide, and water vapor. While it may appear that matter has been destroyed because the ashes weigh less than the original firewood, the gases produced during burning also have mass and are part of the sealed room's total mass.
For instance, consider a room where a 10 kg bundle of firewood burns completely. Initially, there is a fixed amount of mass composed of wood and oxygen. Upon combustion, the wood transforms into less massive ashes, carbon dioxide, and water vapor. Despite the reduction in visible solid material, the mass of gases released during the burning process compensates for this change, leading to a constant total mass for the system of the room.