Calculate the theoretical yield of aspirin if 2.10 grams of salicylic acid was used with excess acetic anhydride. Answer: Theoretical Yield = 2.74g Assume a student reported an 89% yield from the reaction in the problem above. What is the mass of aspirin that’s obtained experimentally?
Original Problem: Calculate the theoretical yield of aspirin if 2.10 grams of salicylic acid was used with excess acetic anhydride.
Assume a student reported an 89% yield from the reaction in the problem above. What is the mass of aspirin that’s obtained experimentally?
The Correct Answer and Explanation is :
To calculate the mass of aspirin obtained experimentally, we use the formula for percent yield:
[
\text{Percent Yield} = \left( \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \right) \times 100
]
Given:
- Percent yield = 89%
- Theoretical yield = 2.74 g
Step 1: Rearrange the percent yield formula to solve for the actual yield.
[
\text{Actual Yield} = \left( \frac{\text{Percent Yield}}{100} \right) \times \text{Theoretical Yield}
]
[
\text{Actual Yield} = \left( \frac{89}{100} \right) \times 2.74 \, \text{g}
]
Step 2: Perform the calculation.
[
\text{Actual Yield} = 0.89 \times 2.74 \, \text{g} = 2.44 \, \text{g}
]
Explanation:
The theoretical yield of aspirin, based on the initial amount of salicylic acid (2.10 grams) and the excess acetic anhydride, was calculated to be 2.74 grams. This represents the maximum amount of aspirin that could be obtained under ideal conditions, where no losses or inefficiencies occur during the reaction.
However, in real experiments, it is common to obtain a yield less than the theoretical yield due to factors such as incomplete reactions, side reactions, or losses during purification. In this case, the student reported an 89% yield, which means they recovered 89% of the theoretical yield.
To calculate the actual mass of aspirin obtained experimentally, we use the percent yield formula. Multiplying the theoretical yield (2.74 g) by 89% (or 0.89) gives us the actual yield of 2.44 grams. This is the mass of aspirin that the student experimentally obtained after performing the reaction.