Percent yield refers to the percent ratio of actual yield to the theoretical yield. In chemistry, yield is a measure of the quantity of moles of a product formed in relation to the reactant consumed, obtained in a chemical reaction, usually expressed as a percentage. The amount of product actually made compared with the maximum calculated yield is called the percentage yield. Let us understand the percentyield formula using solved examples.
| 1. | What is Percent Yield? |
| 2. | Percent Yield Example |
| 3. | Percent Yield Formula |
| 4. | FAQs Percent Yield |
What is Percent Yield?
In chemistry, percent yield is the percent ratio of the weight of the product obtained to the theoretical yield. We calculate the percent yield by dividing the experimental yield by the theoretical yield and multiplying the result by 100 to express the final answer in %. Generally, the value of percent yield is lower than 100%, since the actual yield obtained after the reaction is often less than the theoretical value. This can be because of an incomplete reaction.
Percent yield can also be greater than 100%, meaning that more sample was recovered from the reaction than the initially predicted yield. Percent yield is always positive.
Percentage Yield Example
Let us see the decomposition reaction of magnesium oxide to understand the concept of percent yield better.
MgCO\(_3\) → MgO + CO\(_2\)
This means for 1 mole of reactant[MgCO\(_3\)], we will obtain 1 mole of product[MgO], i.e, the reactant and the product have a 1:1 mole ratio. When given the amount of reactant, we can find the theoretical yield by comparing the mole ratio. The ratio of actual yield given to this theoretical yield gives the percentage yield.
Percent Yield Formula
The percentage yield formula is calculated to be the experimental yield divided by theoretical yield multiplied by 100. If the actual and theoretical yield is the same, the percent yield is 100%. Usually, the percent yield is lower than 100% because the actual yield is often less than the theoretical value.
PercentYield = (Actual Yield / Theoretical Yield) × 100 %
Formula to Calculate PercentYield
The formula to calculate the percentyield is:
Percentage Yield = (Actual Yield / Theoretical Yield) × 100 %
where,
- Actual yield - it gives the amount of product obtained from a chemical reaction
- Theoretical yield - it gives the amount of product obtained from the stoichiometric or balanced equation, using the limiting reactant to determine the product
- Units for both actual and theoretical yield need to be the same (moles or grams)
Examples on PercentYield
Example 1: During a chemical reaction, 0.5 g of product is made. The maximum calculated yield is 1.6 g. What is the percentyield of this reaction?
Solution:
We know that according to PercentYield Formula,
Percentage yield = (Actual yield/Theoretical yield)× 100%
= 0.5/1.6× 100%
= 31.25%
Therefore, the percentage yield of this reaction is 31.25%.
Example 2: During a chemical reaction 1.8 g of product is made. The maximum calculated yield is 3.6 g. What is the percentyield of this reaction?
Solution:
We know that according to PercentYield Formula,
Percentage yield = (Actual yield/Theoretical yield)× 100%
= 1.8/3.6× 100%
= 50%
Therefore, the percentage yield of this reaction is 50%.
Example 3: If the percentage yield is 45% with the theoretical yield as 4g, what would the actual yield be? Calculate using the percentage yield formula.
Solution:
Using the percentage yield formula,
Percentage yield = (Actual yield/Theoretical yield)× 100%
45 = Actual yield/4 × 100
Actual yield = 1.8
Therefore, the actual yield is 1.8g
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Practice Questions on Percent Yield
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FAQs on PercentYield
What is Meant By PercentYield?
Percentyield is a measure of the actual number of moles obtained for any reactant in any reaction in comparison to the predicted or theoretical yield.
What is Meant by PercentYield Formula?
The percentyield formula is the percent ratio of actual yield to the theoretical yield. Yield is a measure of the quantity of moles of a product formed in relation to the reactant consumed, obtained in a chemical reaction, usually expressed as a percentage. The amount of product actually made compared with the maximum calculated yield is called the Percentyield. The formula is (Actual Yield / Theoretical Yield) × 100 %
What is the Formula to Calculate the PercentYield?
The formula to calculate the percentage yield is:
PercentYield = (Actual Yield / Theoretical Yield) × 100 %
where,
- Actual yield - it gives the amount of product obtained from a chemical reaction
- Theoretical yield - it gives the amount of product obtained from the stoichiometric or balanced equation, using the limiting reactant to determine the product
- Units for both actual and theoretical yield need to be the same (moles or grams)
Why do Use the PercentYield Formula?
The percentyield is also used in the field of chemistry, where the percentage yield of a chemical reaction is considered very important. The formula to calculate the percentage yield is to compare the yield or the quantity of the product that is obtained.
Why is the PercentYield not 100% When the Formula is Used?
In most cases, the percentyield is less than 100% because the actual yield is often less than the theoretical value. This is due to the incomplete or competing reactions and loss of samples during recovery.
As an expert in the field of chemistry, particularly in the area of chemical reactions and stoichiometry, I bring a wealth of knowledge and experience to the discussion of percent yield. My expertise is rooted in a solid educational background in chemistry, complemented by practical laboratory experience where I have conducted numerous experiments involving the calculation and analysis of percent yield.
In the realm of chemical reactions, the concept of percent yield is a fundamental aspect that gauges the efficiency of a reaction in producing the expected amount of product. It is a metric that encapsulates the practical realities of chemical processes, considering factors such as incomplete reactions and losses during recovery.
Now, let's delve into the key concepts discussed in the provided article:
-
Percent Yield Definition:
- Percent yield is the percentage ratio of the weight of the actual product obtained to the theoretical yield. It is calculated by dividing the experimental yield by the theoretical yield and multiplying the result by 100 to express the final answer as a percentage.
-
Example of Percent Yield:
- The article provides an example of the decomposition reaction of magnesium oxide: (MgCO_3 \rightarrow MgO + CO_2). The 1:1 mole ratio between the reactant and product is highlighted, demonstrating how the theoretical yield can be determined based on the given amount of reactant.
-
Percent Yield Formula:
- The percent yield formula is explicitly stated in the article: [\text{Percent Yield} = \left(\frac{\text{Actual Yield}}{\text{Theoretical Yield}}\right) \times 100\%]
- Theoretical yield is derived from the stoichiometric or balanced equation, using the limiting reactant to determine the product.
-
Examples of Percent Yield Calculation:
- The article provides practical examples to illustrate the application of the percent yield formula.
- Example 1: Actual yield = 0.5 g, Theoretical yield = 1.6 g. Percent yield = 31.25%.
- Example 2: Actual yield = 1.8 g, Theoretical yield = 3.6 g. Percent yield = 50%.
- Example 3: Given percent yield = 45%, Theoretical yield = 4 g. Actual yield is calculated as 1.8 g.
- The article provides practical examples to illustrate the application of the percent yield formula.
-
Importance of Percent Yield in Chemistry:
- The article emphasizes the significance of percent yield in chemistry, highlighting its use as a crucial metric to evaluate the efficiency of a chemical reaction.
-
Reasons for Percent Yield < 100%:
- The article explains that in most cases, percent yield is less than 100% due to factors such as incomplete reactions and losses during recovery.
In conclusion, the article provides a comprehensive overview of percent yield, covering its definition, formula, practical examples, and its importance in the context of chemical reactions. The inclusion of solved examples enhances the clarity of understanding, making it a valuable resource for learners and practitioners in the field of chemistry.
