Question

define law of conservation of mass and law of constant proportion

Answer 1

law of conservation of mass
the mass can be neither created nor destroyed in a chemical reaction.Thus the amount of matter doesnt change.
law of constant proportion-
it states that every pure substance always contain the same elements combined in same proportions by weight.

Answer 2

Answer:

According to the law of conservation of mass: Matter is neither created nor destroyed in a chemical reaction.

In other words, the law of conservation of mass means that in a chemical reaction, the total mass of products is equal to the total mass of reactants. There is no change in mass during a chemical reaction.