Question

how do balanced chemical equations show the conservation of mass?
they show that the atoms in the products may be different than the reactants as long as the mass does not change.
they show that the atoms in the products are the same as in the reactants, but the number of atoms must change.
they show that the number of atoms of each element is the same in the products and reactants.

Explanation:

To determine the correct answer, we analyze the law of conservation of mass in chemical reactions. The law states that mass is conserved because atoms are neither created nor destroyed, only rearranged. A balanced chemical equation ensures the number of atoms of each element is the same on both sides (reactants and products).

• The first option is incorrect because atoms in products cannot be different from reactants (elements are conserved).
• The second option is incorrect because the number of atoms should not change (atoms are conserved, so their count remains the same).
• The third option correctly states that the number of atoms of each element is the same in products and reactants, which shows mass conservation (since mass of atoms is conserved, same number of each type of atom means same total mass).

Answer:

The correct option is: They show that the number of atoms of each element is the same in the products and reactants.