So in wood combustion we observe solid wood disappear and be converted to gas products, leaving only some ashes. These are formed by minor components of wood that cannot burn and remain solid. 1. Explain what happens to the mass ofa tree when it catches fire and burns until only ashes remain. You must include a chemical equation; discuss the chemical reactions taking place, and the law of conservation of mass in your answer. The wood from the tree has undergone a chemical change. When you burn wood, you are converting the wood into hot gasses. When burning
Cellulose molecules of C6H1005, this produces a lot of H20 and C02. There are large volumes of gasses that are produced during the burning process. The wood is broken down and reformed into other molecules or dissipated as heat and light energy. The wood weight still exists, but in the form of gasses and particulates. Gases have weight, even though they dissipate in the air. The energy that you see in heat, light, and the crackling sound from the fire is liberated stored chemical energy in the chemical bonds that make up that cellulose and other chemical components of the ood.
While the tree burns, it is turning that chemical energy into heat, light and sound. This is the reverse cycle of what the tree did before catching fire. It turned sunlight energy into chemical energy through photosynthesis and the sunlight is necessary in order to take in the carbon dioxide and water and be able to convert that into sugars and cellulose. The products of combustion, when added together (if possible considering most is released into the atmosphere as gases), will have the same mass as what you started with.
When this chemical change takes place, the solid wood disappear and are converted to gas products, leaving only ashes which are formed by some of the components of the wood that cannot burn and they remain solid (ash). The sugar and oxygen molecules disappear and the water and carbon dioxide molecules appear. The molecules are formed by the same atoms that made up the reactant molecules and these atoms are conserved across chemical reactions but are rearranged into different molecules. So taking C6H1006 + 602 = 6C02 + 6H20. This is the wood before and after.
