Answer:
The answer to your question is: mass is constant.
Step-by-step explanation:
To answer your question remember the Law of Conservation of Mass.
This law states that in a closed or isolated system, matter cannot be created or destroyed.
In a closed system there is an interchange of energy with the surroundings but there is not interchange of mass.
In an isolated system there is not interchange of matter and energy with the surroundinsgs.
Then in a chemical reaction, the mass of the reactants is the same of than the mass of the products.