Question

2. In a chemical reaction, the total mass of the products.

A:must always be the same as the total mass of the reactants
B:is always less than the total mass of the reactants in an open system
C:must be less than the total mass of the reactants

Answer 1

A) must always be the same as the total mass of the reactants.

When reactants are transformed into a new substance, all the individual atoms making up the reactants are still present in the products. The reaction doesn’t make new or destroy atoms, so the mass remains constant.