Which law states that the total mass of the reactants is equal to the total mass of the products in a chemical reaction?

Q. Assertion :The balancing of chemical equations is based on law of conservation of mass. Reason: Total mass of reactants is equal to total mass of products.

Q. Assertion :When iron is heated with sulphur, iron sulphide is formed. The total mass of iron and sulphur is equal to the mass of iron sulphide. Reason: Law of conservation of mass states that the total mass of reactants = total mass of products.

Q.

Which of the following statements is correct about the reaction given below ?

$4Fe\left(s\right)+{30}_2\left(g\right)\to 2F{e}_2{0}_3\left(g\right)$

(a) Total mass of iron and oxygen in reactants = total mass of iron and oxygen in product therefore it follows law of conservation of mass

(b) Total mass of reactants = total mass of product, therefore, law of multiple proportions is followed

(c) Amount of $F{e}_2{O}_3$ can be increased by taking any one of the reactants (iron or oxygen) in excess

(d) Amount of $F{e}_2{O}_3$ produced will decrease if the amount of any one of the reactants (iron or oxygen) is taken in excess

Q.

During a physical change or chemical change, the total mass of the products is equal to the total mass of reactants. Which of the following law states that?