Percent Yield
We calculate how much product we produce in a reaction, many times it is larger than what we actually produce. The theoretical yield is the amount of product that is predicted by the the chemical equation (when we do mass to mass conversions and other problems). The actual yield is the actual amount of product produced when you do the reaction in a lab. Almost always, the actual yield will be lower than the theoretical yield. To calculate percent yield, you use the following equation :
For example: Let us say I complete a chemical reaction and get 50 grams of a product (actual yield), but, by using the chemical equation I calculate that I should produce 60 grams of the same product (theoretical yield).
Percent Yield= 50g/60g x 100= 83.33%
Percent Yield= 50g/60g x 100= 83.33%
- In Percent Yield problems, you will always be given the actual yield
- We already know how to calculate theoretical yield (this is what we have been doing in the previous lessons), so this is just one extra small step at the end.