$word_{count}$: 220

Stoichiometry uses balanced equations to relate quantities of reactants and products. Steps: (1) Balance the equation. (2) Convert given quantities to moles. (3) Use mole ratios (coefficients) to find moles of target. (4) Convert to desired units. The limiting reagent is the reactant consumed first — it determines maximum product. Identification: calculate moles of product possible from each reactant separately; the one giving the least is limiting. Alternatively: divide moles of each reactant by its stoichiometric coefficient — smallest quotient is limiting. Excess reagent: amount remaining = initial - amount consumed by limiting reagent. Percent yield = $\frac{actual yield}{theoretical yield}$ x 100. Theoretical yield assumes 100% conversion of limiting reagent. Actual yield is always <= theoretical due to side reactions, equilibrium, and losses. For sequential reactions (A -> B -> C), multiply individual yields: overall = y1 x y2. For gas-phase reactions at same T and P: volume ratios = mole ratios (Avogadro's law). At STP: use 22.4 L/mol. For solutions: moles = molarity x volume(L). These conversions connect different measurement types.