Answer:
The rest of the wood was converted to gases
Explanation:
According to the law of conservation of mass, the mass on the reactant side must be equal to the mass on the product side. When wood is burned it forms ashes and gases. The mass of the ash plus gases must be equal to the mass of the wood and air used in burning it.
If 3g of wood were burned and the ashes produced weighs 1.2g, it means that the rest 1.8g have been converted to gases
