Final answer:
Percent yield is typically less than 100% due to experimental errors, incomplete reactions, side reactions, and impurities. Occasionally, yields can exceed 100% due to impurities or measurement errors inflating the product's weight.
Step-by-step explanation:
Percent yield is defined as the ratio of actual yield to theoretical yield multiplied by 100%. It is often less than 100% due to various factors, including experimental errors such as spills and losses during transfers, incomplete reactions, side reactions that produce unwanted products, and the possibility of impurities in the final product.
In a laboratory setting, a chemist strives for maximum purity and yield, but practical challenges often prevent a percent recovery from being 100%. Sometimes, yields exceeding 100% can occur if extraneous substances like solvents are included in the weight of the product, falsely inflating the yield. Yet, it is important to strive for high percent yields in industry to minimize waste and optimize production efficiency.