How to use it
- Choose what to find: percent yield, actual yield or theoretical yield.
- Enter the known values in grams (any mass unit works if both yields use the same one).
- To calculate the theoretical yield, choose From the limiting reactant and fill in the reactant and product data from the balanced equation.
- Read the result and the shortfall.
Formulas
- Percent yield = actual ÷ theoretical × 100.
- Actual yield = theoretical × percent ÷ 100.
- Theoretical yield = actual ÷ percent × 100.
- From the limiting reactant: theoretical = (mass ÷ M reactant) × (coefficient of product ÷ coefficient of reactant) × M product.
Worked example
Heating 10 g of calcium carbonate, CaCO₃ → CaO + CO₂, gives 5.0 g of calcium oxide. Theoretical: 10 ÷ 100.09 = 0.09991 mol CaCO₃ → 0.09991 mol CaO × 56.08 g/mol = 5.603 g. Percent yield = 5 ÷ 5.603 × 100 = 89.24%.
If you already know that 8.5 g were obtained out of a possible 10 g, the yield is 8.5 ÷ 10 × 100 = 85% and 1.5 g were lost.
Tips
- Use the limiting reactant, the one that runs out first, not the one you have most of.
- Balance the equation first. Wrong coefficients give a wrong theoretical yield.
- Dry the product before weighing, or water will inflate the yield.