Stoichiometry & Percent Yield

Reactants and products are split at the arrow (->, →, = or ⇌) and at each +; a number in front of a formula is its coefficient. Each formula is parsed with the same parser as the molar-mass tool (parentheses, hydrates, subscripts) and its molar mass summed from the IUPAC abridged standard atomic weights. The equation is then checked element by element — the atoms of every element on the left must equal those on the right — and rejected if it is not balanced, because every ratio below depends on the coefficients.

Each reactant amount you give is converted to moles (grams ÷ molar mass, or moles directly). Dividing each by its coefficient gives how many "turns" of the reaction that reactant could support; the smallest is the limiting reagent and that quotient is the reaction extent. Every species then reacts or forms as coefficient × extent: products formed, reactants consumed, and for the excess reactants what remains. Reactants with no amount are assumed to be in excess and are shown as the amount needed.

The theoretical yield of the product you pick is its moles × molar mass — the most you could get if the reaction went to completion with no losses. Percent yield is the mass you actually obtained divided by that, × 100; a figure above 100 % usually means wet or impure product. Reaction conditions, side reactions, equilibrium and purity are outside the page. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.