When balancing chemical equations, why are coefficients adjusted rather than subscripts?

• A. Adjusting coefficients changes the number of molecules without altering the identity of the substances.
• B. Changing subscripts ensures the law of conservation of mass is obeyed.
• C. Adjusting subscripts is easier and does not affect the chemical reaction.
• D. Coefficients are only used to balance ionic equations, not molecular equations.

Answer: (A)

Verified step by step guidance

1. Understand that chemical formulas represent the identity and composition of substances, where subscripts indicate the number of atoms of each element in a molecule.
2. Recognize that changing subscripts alters the fundamental chemical identity of a substance, effectively creating a different compound.
3. Recall the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction, so the number of atoms of each element must be the same on both sides of the equation.
4. Learn that adjusting coefficients changes the number of molecules or formula units involved in the reaction without changing the substances themselves, thus preserving their chemical identity.
5. Conclude that coefficients are adjusted to balance the equation because this method respects both the conservation of mass and the integrity of the chemical substances involved.