Which statement is true for balanced chemical equations?

• A. The total number of molecules is always equal on both sides of the equation.
• B. The mass of reactants can be different from the mass of products.
• C. The coefficients of reactants and products must all be one.
• D. The number of atoms of each element is the same on both sides of the equation.

Answer: (D)

Verified step by step guidance

1. Understand that a balanced chemical equation must obey the Law of Conservation of Mass, which states that matter cannot be created or destroyed in a chemical reaction.
2. Recognize that this means the number of atoms of each element must be the same on both sides of the equation, ensuring mass is conserved.
3. Note that the total number of molecules does not have to be equal on both sides; molecules can combine or break apart, changing their count.
4. Understand that the mass of reactants must equal the mass of products, so the statement that mass can be different is false.
5. Know that coefficients in a balanced equation can be any whole number, not necessarily one, to balance the atoms properly.