When wood burns, the mass of the ash is less than the mass of the original wood. yet the law of conservation of matter says that mass cannot be created or destroyed in a chemical reaction. how do you reconcile the result of burning with this law? (page 112).

Explanation:

According to the law of the conservation of mass, 'mass is conserved in a chemical reaction. The mass cannot be created nor be destroyed in a chemical process'.

This law holds true for the burning of wood also. Although the wood burns to produce ash which weighs less than wood but also, it produces some soot and other gases and the sum of the masses of all these is equal to the sum of the masses of wood and oxygen that reacted with it.