7.3 Reaction Yields
Learning Goals …
… use stoichiometry to determine the theoretical yield of a reaction
… determine the percent yield of a reaction given actual yield
… determine actual yield of a reaction given percent yield
• the amount of product predicted from stoichiometry.
• the amount of product that is obtained from the chemical reaction in an
• this quantity is usually different from theoretical yield.
• sources of error _____________________ of chemicals, products
________________ during heating, __________________ precipitates,
• compares the mass of the product predicted from stoichiometry with that
actually obtained from experiment.
• To calculate Percentage Yield:
Percentage yield = actual yield x 100%
Ex. When 245 kg of arsenic ore (FeSAs) was processed industrially, 95.3 kg of
pure arsenic was obtained. Calculate the percentage yield of arsenic in the
FeSAs (s) FeS (s) + As(s)
Ex. In an experiment, when 16.1 g of FeS reacted with 10.8 g of oxygen gas, 14.1g
of iron(III) oxide was produced. Calculate the percentage yield of iron (III)
oxide in the experiment.
4 FeS + 7 O2 2 Fe2O3 + 4SO2
Ex. If the reaction proceeds with a 92.4% yield of calcium oxide, how many grams
of CaO will be obtained if 12.4 g of calcium carbonate is heated?
CaCO3 (s) CaO (s) + CO2 (g)