Question

If you were to compare the mass of the products and reactants in a reaction, you would find that

The products' mass is always greater.

The reactants' mass is always greater.

The products' mass is equal to the reactants' mass.

The products' mass is always less.

Answer 1

In a chemical reaction you can not create or destroy matter. There must be the same number of each atom present at the end of the reaction as there were at the beginning.

Since all the atoms that were there at the start are still there at the end then the mass has to be the same.

The products mass is equal to the reactants mass

This is the law of conservation of mass.

Answer 2

Unless the reaction is a nuclear reaction, the products' mass is always equal to the reactants' mass, reason being the Law of Conservation of Mass.