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You are watching: How to calculate percent yield of aspirin

The post-lab questions gave are SIMILAR to concerns you may enrespond to in your lab hand-operated. These questions will certainly carry out you with a step-by-step overview on exactly how we approached the problem. You have the right to usage this overview and also the information you videotaped to assist answer the inquiries. Any provided examples via values will certainly be via mock worths. Use of these worths will certainly practically assuredly provide you nonsensical calculations. They are only supposed to highlight the logic. ### question 1

You are asked to calculate the percent yield of aspirin, offer what the worth need to be (theoretical yield), and describe why your worth (actual yield) might differ from this

From the above reaction we recognize the amount of salicylic acid is a 1 to 1 (1:1) ratio via the amount of aspirin. This indicates eexceptionally mole of salicylic acid offered will certainly yield the very same number of moles of aspirin. Because of this, the initially step is to calculate the variety of moles of salicylic acid offered. Note: you are told that acetic anyhydride is in excess and also salicylic acid is the limiting reagent

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

To then transform the number moles of Aspirin to the supposed yield in grams, we multiply the moles by the molar mass of asprin

Moles of Salicylic Acid = Moles of Aspirin —> 2 moles of Salicylic Acid provides 2 moles of Asprin

Molar Mass of Aspirin = 180.16 g

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

Percent Yield Calculation (remember substantial figures)

Your actual yield will be the amount aspirin you weighed after it was filtered and also dried in lab. Using the theoretical and also actual you deserve to calculate percent yield.

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

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

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

Your worth might vary from the theoretical value for a variety of reasons. If it is over 100%, it might be because your aspirin was not completely dried. If it is listed below 100%, it may be because of sample loss once carrying to the weigh paper.

### Question 2

Asks you between aspirin and also salicylic acid, which reacts via FeCl3FeCl3 only reacts with copounds that have phenols. Determine whether aspirin or salicylic acid has a phenol and also that have to be the one that reacts via FeCl3

View fulldimension Phenols (click to enlarge)

### Concern 3

Asks you to find 3 widespread esters and also attract the frameworks.

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