# Calculate the theoretical yield of aspirin based on the number of moles of salicylic acid that you used.

-Calculate the theoretical yield of aspirin based on the number of moles of salicylic acid that you used.
-The questions that are shown after the laboratory experience are VERY SIMILAR to the ones that may be found in your lab handbook. The answers to these questions will walk you through the procedure that we should follow in order to solve the issue.
– You should be able to answer the questions with the assistance of both this instructions and the data that you’ve recorded. Every instance that has a value will also include a mock value. If you use these numbers in your computations, you will almost likely get results that have no sense. Only the purpose of illustrating logic is served by them.

## Calculate the theoretical yield of aspirin based on the number of moles of salicylic acid that you used. ### question 1

You have been tasked with calculating the percent yield of aspirin, providing what the number should be (theoretical yield), and providing an explanation for why your value (actual yield) may differ from this.

As a result of the reaction described above, we know that the quantity of salicylic acid has a ratio of exactly one to one (1:1) with the amount of aspirin. This indicates that the same amount of moles of aspirin will be produced from each mole of salicylic acid that is utilized. Therefore, the first thing that has to be done is to figure out how many moles of salicylic acid were used. Note that you have been informed that acetic anyhydride is in excess and that salicylic acid is the limiting reagent in this experiment.

-Mass of Salicylic Acid Used (mock value) = 276.24 g

-Molar Mass of Salicylic Acid = 138.12 g

-Moles of Salicylic Acid = (1)/(2) = 276.24/138.12 = 2.000 moles

After that, we multiply the number of moles of aspirin by the molar mass of aspirin in order to translate the number of moles of aspirin into the predicted yield in grams.

1. Moles of Salicylic Acid = Moles of Aspirin —> 2 moles of Salicylic Acid makes 2 moles of Asprin

2. Molar Mass of Aspirin = 180.16 g

3. Theoretical yield of Aspirin (g) = (2 moles)(molar mass of aspirin) = 2.000(180.16) = 360.3 grams

Calculation of the Percentage Yield (remember significant figures) The quantity of aspirin that you weighed after it had been filtered and dried in the laboratory will serve as your actual yield. You may determine the percentage yield by using both the theoretical and the real data.

1. Moles of Salicylic Acid = Moles of Aspirin —> 2 moles of Salicylic Acid makes 2 moles of Asprin

2. Molar Mass of Aspirin = 180.16 g

3. Theoretical yield of Aspirin (g) = (2 moles)(molar mass of aspirin) = 2.000(180.16) = 360.3 g

Calculation of the Yield Percentage (remember significant figures)

After being filtered and dried in the laboratory, the quantity of aspirin that will constitute your actual yield will be weighed. The percentage yield may be calculated by using both the theoretical and the actual data.

1. Actual Yield of Aspirin in lab after filtered/dried (mock value) = 370 g

2. Mass of Theoretical Yield of Aspirin (mock value) = 360.3 g

3. Percent Yield = (Actual ÷ Theoretical) x 100 = (370 ÷ 360.3) x 100 = 103 %

There are a lot of factors that might cause your value to diverge from the theoretical value. If it is more than one hundred percent, it is possible that the aspirin you purchased was not entirely dried out. If it is less than one hundred percent, it is possible that some of the sample was lost as it was being transferred to the weigh paper.

### Question 2

You are asked to choose between salicylic acid and aspirin, both of which react with iron chloride.

The element FeCl3 will only react with compounds that include phenols in them. Find out if aspirin or salicylic acid contains a phenol, and if any of them does, the phenol should be the one that interacts with the iron chloride.

## Theoretical Yield Worked Problem

### Problem

Aspirin is prepared from the reaction of salicylic acid (C7H6O3) and acetic anhydride (C4H6O3) to produce aspirin (C9H8O4) and acetic acid (HC2H3O2). The formula for this reaction is

C7H6O3 + C4H6O3 → C9H8O4 + HC2H3O2

How many grams of salicylic acid are needed to make 1,000 1-gram tablets of aspirin? (Assume 100 percent yield.)

### Solution

Step 1: Determine the molar mass of the salicylic acid and the aspirin.

Find the molar mass of aspirin and salicylic acid.

From the periodic table:

Molar Mass of C = 12 grams
Molar Mass of H = 1 grams

Molar Mass of O = 16 grams

MMaspirin = (9 x 12 grams) + (8 x 1 grams) + (4 x 16 grams)
MMaspirin = 108 grams + 8 grams + 64 grams
MMaspirin = 180 grams

MMsal = (7 x 12 grams) + (6 x 1 grams) + (3 x 16 grams)
MMsal = 84 grams + 6 grams + 48 grams
MMsal = 138 grams

The second step is to determine the mole ratio that exists between aspirin and salicylic acid.

One mole of salicylic acid was required for every mole of aspirin that could be manufactured. This results in a mole ratio of one between the two substances.

Step 3: Determine the quantity of salicylic acid required in grams.

The quantity of pills is the place to start when looking for a solution to this issue. The amount of aspirin may be calculated by adding this information to the number of grams that are included in one tablet. The number of moles of aspirin that are created may be determined by using the molar mass of the drug. Calculating the quantity of salicylic acid required to treat the patient requires both this value and the mole ratio. To calculate the number of grams required, use the molar mass of the salicylic acid.

Putting all this together:

grams salicylic acid = 1,000 tablets x 1 g aspirin/1 tablet x 1 mol aspirin/180 g of aspirin x 1 mol sal/1 mol aspirin x 138 g of sal/1 mol sal

grams salicylic acid = 766.67

766.67 grams of salicylic acid are needed to produce 1000 1-gram aspirin tablets.

## F.A.Q 1. calculate the theoretical yield of aspirin based on the number of moles of salicylic acid that you used.

question 1
1. Moles of Salicylic Acid = Moles of Aspirin —> 2 moles of Salicylic Acid makes 2 moles of Asprin.
2. Molar Mass of Aspirin = 180.16 g.
3. Theoretical yield of Aspirin (g) = (2 moles)(molar mass of aspirin) = 2.000(180.16) = 360.3 grams.
The theoretical yield is 5.493 g; the percent yield is 71.4 %.
Thus, the calculated value of crude synthesized aspirin was 3.029 grams. Following purification, the calculated mass of the final aspirin product was 2.169 grams. The calculated theoretical yield was 2.520 grams.
4. Answers will vary. For the sample data, the mass of synthesized aspirin is 1.96 g. Corrected for purity, is: (1.96 × 0.75) = 1.47 g.

Part III Test of the Purity of the Synthesized Aspirin.
Initial mass of aspirin sample (g) 0.200
Moles of salicylic acid in aspirin sample (mol) 1.77 × 104

## Conclusion Paragraph

Based on the empirical formula 1 the mole ratio of salicylic acid to aspirin is 1:1; therefore, to get the theoretical yield of aspirin you need to multiply the number of moles of salicylic acid by the formula mass of aspirin

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