Yield
Definition and meaning of Yield in chemistry.
Yield is the amount of product obtained from a chemical reaction. Percent yield compares the actual product obtained to the theoretical maximum amount that could be produced based on stoichiometry.
In more detail
Every chemical reaction has a theoretical yield, which is the maximum amount of product that could form if the limiting reactant were completely converted to product, assuming no side reactions or losses. In practice, actual yields are usually lower because of incomplete reactions, side reactions, or product loss during collection and purification. Percent yield, calculated as (actual yield ÷ theoretical yield) × 100%, measures how efficiently a reaction converts reactants to the desired product.
Key facts
| Field | General Chemistry |
|---|---|
| Calculation | (Actual yield ÷ Theoretical yield) × 100% |
| Range | 0-100% |
| Purpose | Measures reaction efficiency and product formation success |
When 8 g of methane (CH4) is completely combusted, the theoretical yield of carbon dioxide (CO2) is 22 g. If the reaction produces only 18 g of CO2 in practice, the percent yield is (18 g ÷ 22 g) × 100% = 82%.
Frequently asked questions
Why is percent yield never more than 100%?
The theoretical yield represents the maximum possible amount of product. An actual yield cannot exceed this limit without violating the law of conservation of mass.
How do you determine theoretical yield?
Use stoichiometry and identify the limiting reactant. Calculate how much product could form if all of the limiting reactant converted completely to product with no losses.