Balancing Equations

Objective: Balance simple equations by counting atoms.

A balanced chemical equation has equal counts of each element on both sides because ordinary reactions rearrange atoms without creating or destroying them. Adjust coefficients before complete formulas, not subscripts within formulas. For H₂ + O₂ → H₂O, balanced coefficients are 2, 1, 2: 2H₂ + O₂ → 2H₂O. Count atoms in polyatomic groups carefully and check every element. Coefficients express relative numbers of particles or amount of substance, not necessarily absolute numbers in one sample. State physical conditions when needed; a balanced equation does not by itself prove that the reaction proceeds or predict its rate.

Objective: Apply balancing equations to calculations, evidence, and specified situations.

A balanced chemical equation conserves the count of each element and total charge when ionic species are included. Change coefficients multiplying entire formulas, never the chemical subscripts. Choose the smallest whole-number coefficient set. Check every element after the final adjustment; coefficients may alter several atom counts at once. A balanced equation gives mole ratios, not equal masses or guarantees about reaction rate. The symbolic reactions here are accounting exercises, not laboratory instructions.