Apentix/AP Chemistry/Unit 4: Chemical Reactions/Question
AP Chemistryeasymcq1 pt

Why must a chemical equation be balanced before its mole ratios are used in stoichiometry?

A.Balanced coefficients reflect conservation of atoms and give the true mole ratios
B.Subscripts are adjusted until both sides show the same atom counts
C.Mass would not be conserved unless the equation was written down first
D.Coefficients cancel out once molar masses enter the calculation

Explanation

Core Concept

Atoms are neither created nor destroyed in reactions, so each element must appear in equal numbers on both sides. Once that holds, the coefficients give exact mole ratios connecting every reactant to every product. An unbalanced equation describes a physically impossible process, and any mole conversion built on it inherits the error from the very first step.

Correct Answer

ABalanced coefficients reflect conservation of atoms and give the true mole ratios

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