Written by the Fiveable Content Team โข Last updated September 2025
Written by the Fiveable Content Team โข Last updated September 2025
Definition
Percent yield is the ratio of the actual yield to the theoretical yield, expressed as a percentage. It measures the efficiency of a chemical reaction.
5 Must Know Facts For Your Next Test
Percent yield is calculated using the formula: $\text{Percent Yield} = \left( \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \right) \times 100$.
Actual yield is the amount of product actually obtained from a reaction.
Theoretical yield is the maximum amount of product that could be formed from given reactants, based on stoichiometric calculations.
Percent yield can never exceed 100% because it would indicate more product was obtained than theoretically possible, suggesting an error or contamination.
A low percent yield may indicate incomplete reactions, side reactions, or loss of product during recovery.