How does a balanced chemical equation demonstrate the law of conservation of mass?

• A. It shows that the types of chemical bonds remain unchanged.
• B. It indicates that the number of molecules on both sides must be the same.
• C. It proves that energy is conserved during a chemical reaction.
• D. It shows that the total mass of reactants equals the total mass of products.

Answer: (D)

Verified step by step guidance

1. Understand the law of conservation of mass: it states that mass cannot be created or destroyed in a chemical reaction, so the total mass of reactants must equal the total mass of products.
2. Recognize that a balanced chemical equation has the same number of each type of atom on both sides of the equation, ensuring that no atoms are lost or gained during the reaction.
3. Note that balancing the equation involves adjusting coefficients to make the number of atoms of each element equal on the reactant and product sides, which reflects the conservation of mass.
4. Understand that the balanced equation does not necessarily mean the number of molecules is the same on both sides, but that the total mass (and atoms) is conserved.
5. Conclude that the balanced chemical equation demonstrates the law of conservation of mass by showing that the total mass of reactants equals the total mass of products through equal numbers of atoms.