Percent yield

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

1. Percent yield is calculated using the formula: $\text{Percent Yield} = \left( \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \right) \times 100$.
2. Actual yield is the amount of product actually obtained from a reaction.
3. Theoretical yield is the maximum amount of product that could be formed from given reactants, based on stoichiometric calculations.
4. Percent yield can never exceed 100% because it would indicate more product was obtained than theoretically possible, suggesting an error or contamination.
5. A low percent yield may indicate incomplete reactions, side reactions, or loss of product during recovery.

Review Questions

• What is the formula for calculating percent yield?
• Why can percent yield never exceed 100%?
• What might a low percent yield suggest about a chemical reaction?

Related terms

Actual Yield:

The quantity of product that is actually produced in a chemical reaction.

Theoretical Yield:

The maximum amount of product that could be formed from given reactants based on stoichiometric calculations.

Stoichiometry:

The part of chemistry that deals with the relative quantities of reactants and products in chemical reactions.