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Theoretical and Percent Yield

This site is designed to help students calculate theoretical and percent yield.  There are links at the bottom of this page for additional tutorials, such as how to balance equations, etc.

PLEASE NOTE: LINK TO CRITIQUE IS FOUND AT THE BOTTOM OF THIS PAGE

The general mechanism for finding percentage yield is as follows:
1.  Balance the chemical equation
2.  Find the limiting reagent
3.  Find the theoretical yield
4.  Find the actual yield
5.  Find the percentage yield
 
Percentage Yield =     mass of Actual Yield       x   100%
                                     mass of Theoretical Yield                 
 
 

1.  Balancing The Chemical Equation:

The first step in finding theoretical and percentage yield is to balance the relevant chemical equation. If you are unsure how to do this, click on the "How to Balance Chemical Equations" link below:
 

2.  Finding The Limiting Reagent: 
 
  • this is the reactant which the product yield depends on, as it is not in excess.
  • To determine which reactant is the limiting reagent

              1(a).   Divide the mass (in grams) of the reactant by its molecular weight (in g/mol)  OR

              1(b).   Multiply the amount used (in mL) by its density, then divide by its molar mass

             2.  Multiply the mass (your answer from steps 1(a) or 1(b)) by the number of moles of the reactant used in the reaction.

Unsure of how to calculate molar mass or molecular weight? Click the link below:
 
 

 

3.  Theoretical Yield
  • this is how much product will be synthesized in ideal conditions.
  • To determine theoretical yield, multiply the amount of moles of the limiting reagent by the ratio of the limiting reagent and the synthesized product and by the molecular weight of the product.
 

 

4.  Actual Yield
 
  • this is how much product was actually synthesized in the experiment.
  • Example:  0.135 g acetylsalicylic acid

5.  Percent Yield

  • The percentage yield is the ratio between the actual yield and the theoretical yield multiplied by 100%.  It indicates the percent of theoretical yield that was obtained from the final product in an experiment. 
  • The percentage yield can be calculated using the mass of the actual product obtained and the theoretical mass of the product calculated using the balanced equation of the reaction.
 
Percentage Yield =     Mass of Actual Yield       x   100%
                  Mass of Theoretical Yield
 
 

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