Explain how dalton’s atomic theory offered a convincing explanation of the observation that mass is conserved in chemical reactions

Dalton's atomic theory was based on the law of conservation of mass which states that the matter can neither be created nor be destroyed but it can only transformed into one form or another. In a chemical reaction, total mass of the reactants will be equal to the total mass of the products.

Taking an example,

Mass of = 16g

Mass of =

Total mass on reactant side =

Total mass on reactant side = 80g

Mass of = 44g

Mass of

Total mass on product side =

Total mass on product side = 80g

It is seen from the above example that the

total mass on reactant side = total mass on product side.

not clear

what's the