Theoretical, Actual, Percent Yield & Error - Limiting Reagent and Excess Reactant That Remains
TLDRThis educational video script delves into the concepts of actual yield, theoretical yield, and percent yield in chemical reactions. It guides viewers through balancing chemical equations, identifying limiting reactants, and calculating the amount of excess reactant. The script uses two examples to illustrate the process of determining theoretical and actual yields, as well as the percent yield and error in reactions involving ethane and oxygen, and ethanol and oxygen gas. The explanation simplifies complex chemical concepts, making them accessible for students and educators alike.
Takeaways
- 📚 The video focuses on calculating actual yield, theoretical yield, and percent yield using the formula: percent yield = (actual yield / theoretical yield) * 100.
- 🔍 It explains the difference between a limiting reactant and an excess reactant, and how to identify the limiting reactant through mole per coefficient ratio.
- 🧪 The script provides a step-by-step example of a chemical reaction involving ethane (C2H6) and oxygen, detailing how to balance the equation and calculate yields.
- ⚖️ It demonstrates the process of converting grams to moles and vice versa, which is essential for stoichiometric calculations in chemistry.
- 🔢 The video uses the balanced chemical equation to find the theoretical yield of CO2 in the reaction, which is the maximum amount of product that can be formed.
- 📉 The percent yield is calculated by dividing the actual yield (28 grams of CO2 collected) by the theoretical yield and multiplying by 100, resulting in a yield efficiency.
- 📈 The script explains how to calculate the percent error using the formula: percent error = |(theoretical yield - actual yield) / theoretical yield| * 100.
- 🔄 The concept of finding the amount of excess reactant remaining after the reaction is covered, using the limiting reactant and molar ratios.
- 🌡️ Another example is given involving ethanol and oxygen, where the script shows how to calculate expected CO2 production based on an 85% efficient reaction.
- 🔑 The video emphasizes that the theoretical yield is determined by the reactant that would produce the lesser amount of product when fully reacted.
- 📝 It concludes by reiterating the method to find the actual yield from the theoretical yield and percent efficiency, and determining the amount of excess reactant that reacts and remains.
Q & A
What is the formula for calculating percent yield?
-Percent yield is calculated using the formula: (Actual Yield / Theoretical Yield) × 100.
What is the difference between a limiting reactant and an excess reactant?
-The limiting reactant is the reactant that is completely consumed in a chemical reaction, while the excess reactant is the one that remains after the reaction is complete because it is present in a greater amount than needed for the reaction.
How do you identify the limiting reactant in a chemical reaction?
-The limiting reactant can be identified by comparing the mole ratio of each reactant to its coefficient in the balanced chemical equation. The reactant with the lowest mole-to-coefficient ratio is the limiting reactant.
What is the theoretical yield in a chemical reaction?
-The theoretical yield is the maximum amount of product that can be produced in a chemical reaction based on the stoichiometry of the balanced chemical equation, assuming 100% efficiency.
How can you calculate the actual yield of a reaction given its percent efficiency?
-The actual yield can be calculated by multiplying the theoretical yield by the percent efficiency (expressed as a decimal).
What is the balanced chemical equation for the combustion of ethane (C2H6) with oxygen (O2)?
-The balanced chemical equation for the combustion of ethane is: 2 C2H6 + 7 O2 → 4 CO2 + 6 H2O.
How do you calculate the molar mass of a compound like ethane (C2H6)?
-The molar mass of ethane is calculated by adding the molar masses of all the atoms in the molecule: (2 × 12.01 g/mol for Carbon) + (6 × 1.008 g/mol for Hydrogen), which equals approximately 30.068 g/mol.
What is the relationship between the moles of a reactant and the moles of a product in a chemical reaction?
-The relationship is determined by the stoichiometric coefficients in the balanced chemical equation. For every mole of reactant consumed, a certain number of moles of product is formed, as indicated by the coefficients.
How can you find the amount of excess reactant that remains after a reaction?
-You start with the limiting reactant, convert its grams to moles, then use the molar ratio to find the moles of the excess reactant that reacted. Finally, convert moles of the excess reactant back to grams and subtract from the initial amount to find the remaining excess.
What is the percent error in a chemical reaction, and how is it related to percent yield?
-Percent error is calculated as the absolute value of the difference between the theoretical yield and the actual yield, divided by the theoretical yield, all multiplied by 100. It is related to percent yield in that the sum of percent yield and percent error should equal 100%.
How do you calculate the actual yield of CO2 when given the theoretical yield and the reaction efficiency?
-The actual yield is calculated by multiplying the theoretical yield by the reaction efficiency (as a decimal).
Outlines
🔍 Introduction to Yield Calculations
The video script begins with an introduction to the concepts of actual yield, theoretical yield, and percent yield in chemical reactions. It explains the formula for calculating percent yield and sets the stage for practice problems involving these concepts. The script also mentions the importance of identifying limiting and excess reactants in a reaction and how to calculate the amount of excess reactant remaining after the reaction.
🔬 Balancing Chemical Equations and Identifying Limiting Reactants
This paragraph delves into the process of balancing a chemical equation for a combustion reaction involving ethane and oxygen, resulting in carbon dioxide and water. It guides viewers to balance the equation by first aligning carbon atoms, then hydrogen, and finally oxygen. The script then introduces the method for identifying the limiting reactant by comparing the mole ratios of reactants to their coefficients in the balanced equation, concluding that oxygen is the limiting reactant in the given scenario.
📚 Calculating Theoretical and Actual Yields
The script explains how to calculate the theoretical yield of a reaction by converting the mass of the limiting reactant into the mass of the product using stoichiometric relationships. It details the steps for converting grams of oxygen to moles, then to moles of carbon dioxide, and finally to grams of carbon dioxide. The actual yield is given as the amount of CO2 collected in the experiment, and the theoretical yield is calculated based on the limiting reactant. The difference between theoretical and actual yield is emphasized to understand the efficiency of the reaction.
📉 Understanding Percent Yield and Percent Error
This section of the script focuses on the calculation of percent yield using the actual and theoretical yields. It provides the formula for percent yield and demonstrates its application with the given data. The concept of percent error is introduced as the complement to percent yield, explaining that the sum of percent yield and percent error equals 100%. The script illustrates how to calculate percent error and emphasizes the relationship between yield and error in chemical reactions.
🔄 Determining Excess Reactant Remaining
The script explains how to calculate the amount of excess reactant that remains after a chemical reaction. It uses the example of ethane and oxygen, starting with the limiting reactant (oxygen) and converting its grams into moles of the excess reactant (ethane). The process involves using the molar ratio from the balanced equation and converting moles back to grams. The remaining excess reactant is found by subtracting the amount that reacted from the initial amount present.
🌡️ Efficiency and Reactant Relationships in Combustion Reactions
This paragraph introduces a new problem involving ethanol and oxygen in a combustion reaction, with a given percent efficiency. The script outlines the steps to balance the chemical equation and explains two methods for identifying the limiting reactant: one based on mole ratios and coefficients, and another based on comparing theoretical yields of products from each reactant. It concludes that oxygen is the limiting reactant and ethanol is in excess, with theoretical yield calculations based on the reactant that limits the production of CO2.
📊 Calculating Actual Yield with Given Efficiency
The script provides a method for calculating the actual yield of a reaction based on its efficiency. It demonstrates how to find the actual yield by taking a percentage of the theoretical yield, using the given 85% efficiency as an example. The actual yield is then used to determine the amount of CO2 expected from the reaction. The script also explains an alternative approach using the percent yield formula to find the actual yield from the theoretical yield and vice versa.
🧐 Conclusion on Limiting Reactants and Excess Reactants
The final paragraph wraps up the video by summarizing the concepts of limiting and excess reactants, and how to calculate the amount of excess reactant remaining after a reaction. It reiterates the importance of understanding these concepts for solving stoichiometry problems in chemistry. The script concludes by encouraging viewers to apply these methods to similar problems and thanks them for watching.
Mindmap
Keywords
💡Actual Yield
💡Theoretical Yield
💡Percent Yield
💡Limiting Reactant
💡Excess Reactant
💡Combustion Reaction
💡Molar Mass
💡Mole Ratio
💡Percent Error
💡Stoichiometry
Highlights
Introduction to calculating actual yield, theoretical yield, and percent yield using the formula: percent yield = (actual yield / theoretical yield) * 100.
Explanation of the difference between a limiting reaction and an excess reactant and the method to find them.
Demonstration of balancing a chemical equation for a combustion reaction involving ethane and oxygen.
Step-by-step guide on converting grams to moles using molar mass for ethane and oxygen.
Identification of the limiting reactant by comparing the mole per coefficient ratio of reactants.
Calculation of the theoretical yield of CO2 in a combustion reaction using the limiting reactant.
Explanation of how to find the actual yield from the theoretical yield and percent efficiency.
Calculation of percent yield using the actual yield and theoretical yield.
Introduction of the percent error equation and its calculation.
Method to determine the amount of excess reactant remaining after the reaction.
Application of the process to a second problem involving ethanol and oxygen with given percent efficiency.
Balancing of the ethanol combustion reaction and identification of the limiting reactant.
Calculation of the theoretical yield for both reactants and determination of the limiting reactant.
Conversion of theoretical yield to actual yield using the given percent efficiency.
Calculation of the amount of excess reactant that actually reacts and the amount that remains.
Summary of the concepts learned regarding limiting and excess reactants and their practical applications.
Transcripts
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