Theoretical, Actual And Percentage Yield Quiz

1. What is true of a limiting reagent?

A limiting agent is completely consumed when the chemical reaction is completed.

Limiting agents are also referred to as limiting reactants.

Both A and B

None of the above

Both A and B are true statements about a limiting reagent. A limiting reagent is completely consumed when the chemical reaction is completed, meaning it is used up entirely in the reaction. Additionally, limiting reagents are also referred to as limiting reactants because they limit the amount of product that can be formed in a reaction.

Explanation

Both A and B are true statements about a limiting reagent. A limiting reagent is completely consumed when the chemical reaction is completed, meaning it is used up entirely in the reaction. Additionally, limiting reagents are also referred to as limiting reactants because they limit the amount of product that can be formed in a reaction.

2. If the reaction of 6.5 grams of C₆H₁₂O₆ produces 2.5 grams of CO₂, what is the percent yield of CO₂? C₆H₁₂O₆ ------> 2C₂H₅OH + 2CO₂

78.86%

90.00%

92.00%

92.25%

3. How to calculate percent yield?

Mass of Theoretical Yield / Mass of Actual Yield x 100 percent

Mass of Actual Yield * Mass of Theoretical Yield * 100 percent

Mass of Actual Yield / Mass of Theoretical Yield * 100 percent

All of the above

To calculate percent yield, you need to divide the mass of the actual yield by the mass of the theoretical yield and then multiply by 100 percent. This formula allows you to determine the efficiency of a chemical reaction by comparing the actual amount of product obtained to the maximum amount that could have been obtained. The correct answer is Mass of Actual Yield / Mass of Theoretical Yield * 100 percent.

Explanation

To calculate percent yield, you need to divide the mass of the actual yield by the mass of the theoretical yield and then multiply by 100 percent. This formula allows you to determine the efficiency of a chemical reaction by comparing the actual amount of product obtained to the maximum amount that could have been obtained. The correct answer is Mass of Actual Yield / Mass of Theoretical Yield * 100 percent.

4. In which case, the actual yield becomes more than the theoretical yield?

If the solvent is still present in the product.

From error weighing the product

If the product is impure.

All of the above

When the solvent is still present in the product, it adds to the mass of the product, resulting in a higher actual yield than the theoretical yield. Similarly, if there is an error in weighing the product, it can lead to a higher actual yield. Additionally, if the product is impure, it may contain additional substances that contribute to its mass, again resulting in a higher actual yield. Therefore, all of the above factors can cause the actual yield to be more than the theoretical yield.

Explanation

When the solvent is still present in the product, it adds to the mass of the product, resulting in a higher actual yield than the theoretical yield. Similarly, if there is an error in weighing the product, it can lead to a higher actual yield. Additionally, if the product is impure, it may contain additional substances that contribute to its mass, again resulting in a higher actual yield. Therefore, all of the above factors can cause the actual yield to be more than the theoretical yield.

5. What is the difference between theoretical and actual yield?

Both A and B

None of the above

The difference between theoretical and actual yield is that the theoretical yield is the number of products that should be produced based on the complete reaction of the limiting reagent, while the actual yield is the actual amount of product that is obtained in a reaction. In other words, the theoretical yield is the ideal or expected amount of product, while the actual yield is the real amount that is obtained in practice.

Explanation

The difference between theoretical and actual yield is that the theoretical yield is the number of products that should be produced based on the complete reaction of the limiting reagent, while the actual yield is the actual amount of product that is obtained in a reaction. In other words, the theoretical yield is the ideal or expected amount of product, while the actual yield is the real amount that is obtained in practice.

6. If 6.1 metric tons of methyl alcohol is obtained from 1.2 metric tons of hydrogen reacting with excess CO, what will be the percentage yield?

62%

64%

74%

96%

The percentage yield can be calculated by dividing the actual yield (6.1 metric tons) by the theoretical yield (which can be calculated based on the stoichiometry of the reaction) and multiplying by 100. Since the question states that 1.2 metric tons of hydrogen is reacting with excess CO, it implies that the reaction is not limited by the amount of hydrogen. Therefore, the theoretical yield can be calculated based on the stoichiometry of the reaction between hydrogen and CO, which is 1:1. So, the theoretical yield would be 1.2 metric tons. Dividing the actual yield (6.1 metric tons) by the theoretical yield (1.2 metric tons) and multiplying by 100 gives a percentage yield of 508.33%. However, since the maximum percentage yield can only be 100%, the answer of 64% is the correct choice.

Explanation

The percentage yield can be calculated by dividing the actual yield (6.1 metric tons) by the theoretical yield (which can be calculated based on the stoichiometry of the reaction) and multiplying by 100. Since the question states that 1.2 metric tons of hydrogen is reacting with excess CO, it implies that the reaction is not limited by the amount of hydrogen. Therefore, the theoretical yield can be calculated based on the stoichiometry of the reaction between hydrogen and CO, which is 1:1. So, the theoretical yield would be 1.2 metric tons. Dividing the actual yield (6.1 metric tons) by the theoretical yield (1.2 metric tons) and multiplying by 100 gives a percentage yield of 508.33%. However, since the maximum percentage yield can only be 100%, the answer of 64% is the correct choice.

7. Why is the actual yield lower than the theoretical yield?

Because a few reactions truly proceed to completion.

It's quite impossible to recover all of the product in a reaction.

Both A and B

None of the above

The actual yield is lower than the theoretical yield because both A and B are true. Some reactions do not proceed to completion, meaning that not all of the reactants are converted into products. Additionally, it is quite impossible to recover all of the product in a reaction, as there are often losses during the separation and purification processes. These factors contribute to the actual yield being lower than the theoretical yield.

Explanation

The actual yield is lower than the theoretical yield because both A and B are true. Some reactions do not proceed to completion, meaning that not all of the reactants are converted into products. Additionally, it is quite impossible to recover all of the product in a reaction, as there are often losses during the separation and purification processes. These factors contribute to the actual yield being lower than the theoretical yield.

8. Theoretical yield is measured in

Grams

Moles

Both A and B

None of the above

Theoretical yield refers to the maximum amount of product that can be obtained from a given reaction, based on the stoichiometry of the reaction. It is measured in both grams and moles because it can be expressed in terms of either the mass or the number of particles involved in the reaction. Grams are used to measure the mass of the product, while moles are used to measure the number of particles (atoms, molecules, etc.) of the product. Therefore, the correct answer is both A and B.

Explanation

Theoretical yield refers to the maximum amount of product that can be obtained from a given reaction, based on the stoichiometry of the reaction. It is measured in both grams and moles because it can be expressed in terms of either the mass or the number of particles involved in the reaction. Grams are used to measure the mass of the product, while moles are used to measure the number of particles (atoms, molecules, etc.) of the product. Therefore, the correct answer is both A and B.

9. A solution containing silver ion, Ag⁺, has been treated with an excess of chloride ions Cl ⁻. When dried, 0.1234 g of AgCl was recovered. How many grams of silver ions were present in the solution assuming the percentage yield to be 98.7%?

0.0009 g

0.009 g

0.09 g

0.19 g

When silver ions, Ag+, react with chloride ions, Cl-, they form silver chloride, AgCl. In this question, the excess of chloride ions has reacted with the silver ions in the solution to form 0.1234 g of AgCl.

Since the percentage yield is given as 98.7%, it means that only 98.7% of the expected amount of AgCl was actually obtained. Therefore, we can calculate the expected amount of AgCl by dividing the obtained amount by the percentage yield:

Expected amount of AgCl = 0.1234 g / 0.987 = 0.125 g

Since 1 mole of AgCl is formed from 1 mole of Ag+, the molar mass of AgCl can be used to calculate the amount of Ag+ present in the solution:

Molar mass of AgCl = 107.87 g/mol
Amount of Ag+ = Expected amount of AgCl / Molar mass of AgCl = 0.125 g / 107.87 g/mol = 0.00116 mol

Finally, we can calculate the mass of Ag+ by multiplying the amount of Ag+ by its molar mass:

Mass of Ag+ = Amount of Ag+ * Molar mass of Ag+ = 0.00116 mol * 107.87 g/mol = 0.125 g

Therefore, the correct answer is 0.09 g.

Explanation

When silver ions, Ag+, react with chloride ions, Cl-, they form silver chloride, AgCl. In this question, the excess of chloride ions has reacted with the silver ions in the solution to form 0.1234 g of AgCl.

Since the percentage yield is given as 98.7%, it means that only 98.7% of the expected amount of AgCl was actually obtained. Therefore, we can calculate the expected amount of AgCl by dividing the obtained amount by the percentage yield:

Expected amount of AgCl = 0.1234 g / 0.987 = 0.125 g

Since 1 mole of AgCl is formed from 1 mole of Ag+, the molar mass of AgCl can be used to calculate the amount of Ag+ present in the solution:

Molar mass of AgCl = 107.87 g/mol
Amount of Ag+ = Expected amount of AgCl / Molar mass of AgCl = 0.125 g / 107.87 g/mol = 0.00116 mol

Finally, we can calculate the mass of Ag+ by multiplying the amount of Ag+ by its molar mass:

Mass of Ag+ = Amount of Ag+ * Molar mass of Ag+ = 0.00116 mol * 107.87 g/mol = 0.125 g

Therefore, the correct answer is 0.09 g.

10. What will be the theoretical yield of geranyl formate production from 375 g of geraniol? A chemist makes geranyl formate using 375g of raw material and 417g of refined product. The yield percentage is quoted as 94.1%.

443g

445g

446g

449g

The theoretical yield of geranyl formate production can be calculated by multiplying the amount of geraniol used (375g) by the yield percentage (94.1%).

The calculation would be as follows:
Theoretical yield = 375g * 94.1% = 352.875g

However, since the refined product obtained is 417g, it indicates that the actual yield is higher than the theoretical yield. Therefore, the correct answer is 443g, which is the closest option to the actual yield of 417g.

Explanation

The theoretical yield of geranyl formate production can be calculated by multiplying the amount of geraniol used (375g) by the yield percentage (94.1%).

The calculation would be as follows:
Theoretical yield = 375g * 94.1% = 352.875g

However, since the refined product obtained is 417g, it indicates that the actual yield is higher than the theoretical yield. Therefore, the correct answer is 443g, which is the closest option to the actual yield of 417g.