Lesson-specific diagram for Chemical equations as conservation models. It visualizes the reasoning sequence tied to $\text{reactants}\to\text{products};\;N_{atoms,i}=N_{atoms,f}$. Text alternative: A balanced equation is a particle-ratio model that conserves atoms and charge, not a statement that reactant and product masses are numerically equal term-by-term. Choose a representation that matches the chemical scale and evidence; do not infer more precision or mechanism than the data support.