How does the combustion of wood primarily affect its mass?

The combustion of wood primarily results in a decrease in mass because, during the burning process, the organic compounds in the wood are transformed into gases such as carbon dioxide and water vapor. When wood burns, the cellulose and lignin in the wood are oxidized, and energy is released in the form of heat and light. This transformation leads to a significant portion of the material being converted into gases that disperse into the atmosphere, which ultimately contributes to a reduction in the total mass of the wood.

Furthermore, the remaining ash is the solid residue that consists mostly of inorganic mineral elements that were not combusted. However, the mass of the ash is far less than the original mass of the wood due to the substantial loss of gaseous products. Thus, the overall mass decreases as the wood is consumed in the combustion process.