Which condition must be met in order for a chemical equation to be considered balanced?

• A. The sum of the coefficients on the reactant side equals the sum on the product side.
• B. The number of atoms of each element is the same on both sides of the equation.
• C. The total number of molecules is the same on both sides of the equation.
• D. The equation contains only ionic compounds.

Answer: (B)

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 the reactant and product sides of the equation.
3. Note that simply having the same total number of molecules or the same sum of coefficients does not guarantee the equation is balanced, because different molecules can contain different numbers of atoms.
4. Focus on counting the atoms of each element individually on both sides of the equation to ensure they are equal.
5. Conclude that the key condition for a chemical equation to be balanced is that the number of atoms of each element is the same on both sides of the equation.