Which statement correctly describes the relationship between the amount of reactant used and the percent yield in a chemical reaction?

• A. Increasing the amount of reactant always increases the percent yield.
• B. Percent yield is calculated by dividing the theoretical yield by the actual yield and multiplying by 100%.
• C. Percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100%.
• D. Percent yield is independent of the amount of reactant used.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the definition of percent yield. Percent yield is a measure of the efficiency of a chemical reaction, comparing the amount of product actually obtained (actual yield) to the amount predicted by stoichiometry (theoretical yield).
2. Step 2: Recall the formula for percent yield, which is given by: \(\text{Percent Yield} = \left( \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \right) \times 100\%\).
3. Step 3: Analyze the relationship between the amount of reactant and percent yield. While increasing the amount of reactant can increase the amount of product formed, it does not necessarily change the percent yield, which depends on reaction efficiency and conditions.
4. Step 4: Recognize that percent yield is independent of the scale of the reaction; it depends on how much product is actually formed relative to the maximum possible amount, not just on the quantity of reactant used.
5. Step 5: Conclude that the correct description is that percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100%, and that percent yield does not always increase with more reactant.