Which of the following is true when balancing chemical equations?

• A. Only the products need to be balanced, not the reactants.
• B. Coefficients can be fractional to balance the equation.
• C. Subscripts of compounds can be changed to balance the equation.
• D. The number of atoms of each element must be the same on both sides of the equation.

Answer: (D)

Verified step by step guidance

1. Understand that balancing chemical equations requires the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.
2. Recognize that the number of atoms of each element must be the same on both the reactant and product sides of the equation to satisfy this law.
3. Know that coefficients (the numbers placed before compounds) are used to balance the equation, and these coefficients can be whole numbers or sometimes fractional during intermediate steps, but the final balanced equation usually uses whole numbers.
4. Remember that subscripts in chemical formulas represent the fixed composition of compounds and should never be changed to balance an equation, as changing subscripts changes the identity of the substances involved.
5. Conclude that the correct approach is to adjust coefficients to ensure the number of atoms of each element is equal on both sides, confirming that the statement 'The number of atoms of each element must be the same on both sides of the equation' is true.