Percent yield expresses how much product was obtained compared to the maximum possible amount.

• A. Percent yield equals actual yield divided by theoretical yield
• B. Percent yield equals theoretical yield divided by actual yield
• C. Percent yield equals actual yield divided by theoretical yield multiplied by 1000
• D. Percent yield equals actual yield divided by theoretical yield multiplied by 100

Answer: (D)

Percent yield tells you how efficient a reaction was by comparing what you actually obtained to the maximum amount you could have produced from the reactants. You calculate it by dividing the actual yield by the theoretical yield and then multiplying by 100 to turn that ratio into a percentage. The theoretical yield comes from stoichiometry assuming complete reaction with the limiting reagent. For example, if the reaction could theoretically give 5.0 g but you only collected 4.5 g, the percent yield is (4.5/5.0) × 100 = 90%. Using 1000 would give an irrelevant value, and omitting the ×100 would give a decimal fraction rather than a percent.