10. Which best explains why the total mass of the product(s) would be less than the total weight of the reactant(s) after a chemical reaction?
А
A physical change occurred.
B
Atoms involved in the reaction lost mass.
с
Precipitates were created in the new solution.
D
Gases were released to the atmosphere.

D. Gases were released to the atmosphere

Explanation:

In accordance to the law of conservation of mass, the total amount of reactants must equate the total amount of products at the end of the reaction because matter can not be lost or created. However, certain changes like gas evolution, formation of precipitate etc. indicates the occurrence of a chemical reaction.

In a chemical reaction, the total mass of the product(s) would be less than the total weight of the reactant(s) because GASES, which constituted part of the mass of the reaction, WERE RELEASED INTO THE ATMOSPHERE. However, if the mass of the gas released can be accounted for, the amount of reactants and products must balance.