Knowledge database: 4.6 Yield

The yield of a chemical reaction measures how much of the theoretical amount of the product is produced in a real chemical reaction.

A simple formula which additionaly explains the yield, can be seen on the picture above. Yield is calculated by dividing the experimentally determined mass or amount of the product, by the theoretical mass or amount of the product. To get the yield expressed as a percentage, the obtained value is simply multiplied by 100.

The theoretical mass of the product is calculated by taking the limiting reagent into account, since this reagent determines to which extent will the reaction be completed.

A yield of 100% is not possible, because of the limitations of the measuring equipment. Yield around 90% is considered to be excellent, at about 80% it is called very good, and about 70% is considered to be good. Yield around 50% is considered to be fair, while anything below 40% is called poor.