Chemistry--How did Dalton's theory explain the law of conservation of mass?

Answer 1

John Dalton claimed "that each chemical element is composed of atoms of a single, unique type, and that though they are both immutable and indestructible, they can combine to form more complex structures (chemical compounds)."

The Law of Conservation of Mass states that "the total mass in a chemical reaction remains constant (that is, the reactants have the same mass as the products)."

But this (conservation of mass) can only be possible if John Dalton was indeed correct about the fact that atoms are "immutable and indestructible."

For instance, if atoms could be destroyed in a reaction, then the mass of the products would not equal the mass of the reactants; hence the Law of Conservation of Mass would not apply.

Answer 2

For #2, Dalton didn't know about isotopes as neutrons had not yet been discovered.

Answer 3

since, according to dalton, all atoms could not be broken down or destroyed, there must be just as many atoms at the start of a reaction as there is at the end; they must be just arranged differently.