Percent Yield Calculator

The percent yield calculator helps you to calculate the percent yield value for a given amount of theoretical and actual yield. This is the ideal way to find the synthetic reaction that is done during lab experiments.

What is Yield?

The amount of product that is obtained by the chemical reaction is known as yield. 

• A higher yield shows that the reaction is efficient in which the product is formed in good quantity.
• A low yield indicates that reaction is inefficient in which the desired product is not being formed in good quantity.

What Is Percent Yield? 

Percent yield is the ratio between the mass of the actual yield and the theoretical yield of the chemical reaction.

Percent Yield Formula: 

Percent yield is the division of actual yield to the predicted theoretical yield. This yield percent is evaluated by the following formula:

Percent Yield formula = mass actual yield/mass theoretical yield * 100%

How To Calculate Percent Yield?

The calculator tells how well you carried out your reaction. In order to understand the manual calculations in the best way look at a couple of examples below:

Example # 1:

In a lab experiment, 50 grams of product were obtained and if the theoretical yield was determined to be 60 grams then, the percent yield would be?

Solution:

Percent Yield = (Actual Yield / Theoretical Yield) * 100

Put the values in the formula:

= (50 / 60) x 100

= 83.33%

This indicates that the experiment yielded 83.33% of the expected product.

Example # 2:

When 16.0 g of calcium carbonate (CaCO3) is heated to thermal decomposition, 7.54 g of calcium oxide (CaO) is obtained. How to calculate percent yield using the percentage yield formula?

CaCO3 →CaO   +   CO2

Solution:

One mole of calcium carbonate gives one mole of calcium oxide. 

• The molar mass of calcium carbonate = 100 g/mol
• The molar mass of calcium oxide = 56 g/mol

It means that if 100 g of CaCO3 was burnt, it gave 56 g of CaO. But in this experiment, 16 g of CaCO3 was burnt, then the amount of CaO would be:

Hypothesis Mass = 56 g / 100 g * 16 g 

Hypothesis Mass = 8.96 g 

Now substitute the actual yield and the hypothesis mass of the chemical reaction to calculate the percent yield into the formula

Percent yield = 7.54 g / 8.96 g * 100 

Percent yield = 84.16 % 

FAQs:

Why Is the Actual Yield Smaller Than the Theoretical Yield?

The actual yield is always smaller than the expected yield due to experimental errors and the affected factors. The factors are: 

• Loss of the product
• Presence of impurities 
• Some reactants escape into the air
• Some reactants don’t convert into the product 
• Unwanted products are formed in a side reaction

When The Percent Yield is 100%?

If the actual yield equals the hypothesis yield, then the percent yield is 100%.

Does Increasing Pressure Cause To Increase In the Yield?

Yes, increasing pressure causes the enhancement of the yield. At increasing pressure, moles of gaseous atoms decrease, equilibrium will shift in the forward direction, and the product yield will increase.

How Do Impurities Affect the Percent Yield?

The existence of impurities decreases the actual yield. As a result, it decreases the percent yield. The purity of the reactant is the factor that affects the percentage yield. Highly pure reactants tend to increase the actual yield and the percentage yield.  

How We Increase the Percent Yield?

It is important to follow the points below to increase the percent yield of the chemical reaction.

• Use clean glass
• Evaluate the exact amount of reagents weigh
• Purify reagents and solvent
• Must use the pure reactant
• Wash flasks and syringes used to transfer the reactant

References:

Wikipedia: Annual percentage yield, Equation.

Khan Academy: Limiting reactant and reaction yields, Limiting reactant and theoretical yield, Worked example, Stoichiometry.