Final answer:
The percentage yield of a chemical reaction is the ratio of the actual yield to the theoretical yield, expressed as a percentage. It is typically less than 100% due to various factors. Chemists aim to purify reaction products for accurate percent yield calculations.
Step-by-step explanation:
The percentage yield of a chemical reaction is the ratio of the actual yield of the reaction to the theoretical yield, multiplied by 100 to give a percentage. It can be calculated using the formula:
Percentage Yield = (Actual Yield / Theoretical Yield) x 100%
For example, if the theoretical yield of a reaction is 100 grams and the actual yield is 75 grams, the percentage yield would be:
Percentage Yield = (75 / 100) x 100% = 75%
Percent yields are typically less than 100% due to various reasons, including side reactions, incomplete reactions, and loss of product during collection. However, percent yields greater than 100% can be possible if the measured product contains impurities. Chemists always strive to purify the reaction products to obtain accurate percent yields.