Contents
Key Stage 3
Meaning
The percentage yield is the mass of a product in an chemical reaction compared to the mass that could theoretically be produced in a perfect reaction as a percentage.
About Percentage Yield
- The percentage yield is useful to work out the efficiency of a chemical reaction and considering the cost of forming the desired product.
Equation
Percentage Yield = (Actual mass of product / Theoretical maximum mass of product)x100%
Percentage Yield = \(\frac{M_A}{M_T}*100%\)
Where:
Factors Affecting Percentage Yield
- Reversible Reactions - Some reactions are reversible which means the products may react to form the original reactants resulting in less than 100% of the theoretical maximum mass of product.
- Purity of Reactants - If the reactants are not pure then there is not as much of the original chemicals as was believed, resulting in less product being formed.
- Collection of Product - Collecting and separating out the products may not be an easy process and some of the product may be lost in the process.
- Unwanted Reactions - Sometimes there may be other chemical reactions which take place in the reaction mixture, this may reduce the amount of desired product.