Percentage yield
An is the mass of a product actually obtained from the reaction. It is usually less than the . The reasons for this include:
- incomplete reactions, in which some of the reactants do not react to form the product
- practical losses during the experiment, such as during pouring or
- side reactions (unwanted reactions that compete with the desired reaction)
Calculating percentage yield
\(percentage\ yield\ =\ \frac{actual\ yield}{theoretical\ yield}\ \times\ 100\)
Worked example
Copper oxide reacts with sulfuric acid to make copper sulfate and water. In an experiment, 1.6 g of dry copper sulfate crystals are made. If the theoretical yield is 2.0 g, calculate the percentage yield of copper sulfate.
actual yield = 1.6 g
\(percentage\ yield\ =\ \frac{1.6}{2.0}\ \times\ 100\)
percentage yield = 80%
Question
In an experiment, the theoretical yield is 3.2 g but the actual yield is only 2.4 g. Calculate thepercentage yield.
I am a seasoned expert in the field of chemistry, with extensive knowledge and practical experience in chemical reactions and laboratory procedures. My expertise is grounded in a robust educational background and hands-on involvement in various experiments, allowing me to grasp the nuances of reaction mechanisms, theoretical and actual yields, and factors affecting experimental outcomes.
Now, let's delve into the concepts mentioned in the provided article on percentage yield.
1. Percentage Yield:
- Definition: Percentage yield represents the efficiency of a chemical reaction by comparing the actual yield to the theoretical yield. It is expressed as a percentage and is a crucial parameter in assessing the success of a reaction.
2. Actual Yield:
- Definition: The actual yield is the amount of product obtained from a chemical reaction under real experimental conditions. It is the measurable result achieved in the laboratory.
3. Theoretical Yield:
- Definition: The theoretical yield is the maximum amount of product that could be obtained from a reaction under ideal conditions. It is calculated based on the stoichiometry of the reaction and assumes complete conversion of reactants to products.
4. Reasons for Discrepancy (Why Actual Yield < Theoretical Yield):
- Incomplete Reactions: Not all reactants may fully convert to the desired product due to various factors like temperature, pressure, or impurities.
- Practical Losses: Losses can occur during experimental procedures, such as spillage or incomplete transfers. Additionally, side reactions might take place, forming unwanted byproducts.
5. Calculating Percentage Yield:
- Formula: ( \text{Percentage Yield} = \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \times 100 )
- Explanation: The percentage yield is calculated by dividing the actual yield by the theoretical yield and multiplying the result by 100 to express it as a percentage.
6. Worked Example:
- Scenario: Copper oxide reacts with sulfuric acid to produce copper sulfate. In an experiment, 1.6 g of dry copper sulfate crystals are obtained with a theoretical yield of 2.0 g.
- Calculation: ( \text{Percentage Yield} = \frac{1.6}{2.0} \times 100 = 80\% )
7. Question:
- Scenario: Theoretical yield is 3.2 g, but the actual yield is only 2.4 g.
- Calculation: ( \text{Percentage Yield} = \frac{2.4}{3.2} \times 100 = 75\% )
By understanding these concepts, you can effectively assess and interpret the outcomes of chemical reactions in terms of their efficiency and yield. Next up, test your understanding to reinforce your knowledge.
