Synthesizing Aspirin PDF

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Sharlene Wang CHE 111-013 Xiaojing Wang Maggie Almsari 9 March 2020

Testing the Purity of Aspirin Introduction: Aspirin is the most mass-produced drug in the world. Aspirin is the combination of acetic anhydride and salicylic acid with the appearance of phosphoric acid. Years ago, salicylic acid was used to cure headaches but years later, they found that salicylic acid was too acidic for the stomach and mouth. So, nowadays, people use ibuprofen in place of salicylic acid. The purpose of this experiment is to test the purity of aspirin. Our hypothesis for this experiment was that the solution was going to come out clear. In the end, the solution for synthesizing aspirin should be clear meaning there will be no salicylic acid left. If there is a slight violet color, that means there is salicylic acid present. When starting a lab, you have to accurately measure out all of your reagents. Limiting Reagent is the product that is used up first and controls how much is produced. It is determined by how much you started with in the beginning. To find the limiting reagent, you have to use a chemical balanced equation, determine how many moles of each reagent there is, and in the end, find the number of moles produced for each reagent. Therefore, you will know which one is your limiting reagent.

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After determining your limiting reagent, you will then use the theoretical and percent yields. “Theoretical yield is the maximum amount of product that you can recover from your experimental conditions” (French et al. 83-88). To determine the theoretical yield, you need to transform the number of moles of product to grams. But, in the lab, it is natural to lose products along the way, so the calculation may be less than what you calculated. The equation below help you calculate the percent yield: % yield= actual yield/ theoretical yield*100 or = amount of product recovered/ theoretical amount of product*100

Recrystallization is the process where you separate the solids from other impurities in the solution. It involves three simple steps: 1) Dissolution of the solid to be purified in some hot solvent. (French et al. 83-88) 2) Formation of crystals as the solution cools. (French et al. 83-88) 3) Recovery of the purified crystals, usually by filtration. The impurities are left in solution. (French et al. 83-88) The main objective of this experiment is to test the purity of aspirin. “A functional group is a group of atoms that have characteristic reactivity. The phenol functional group is defined as being an –OH group attached to a benzene ring” (French et al. 83-88). To test the purity, you have to use the equation: 6C6H5OH + Fe3+ + → [Fe(OC6H5)6]3- + 6H+ If the solution is a violet color, there is no more salicylic acid in the solution. If the color is violet, your solution still has salicylic acid. 2

Methods: No changes were made in this experiment. (French et al. 83-88) Discussion: The purpose of this experiment is to test the purity of aspirin. The ideal end result of the solution should be clear. The actual yield of the experiment was 1.1289 and the theoretical yield is 2.715. Therefore, the percent yield for the synthesis of aspirin was 41.6%. This proved our hypothesis to be correct because of our low percent yield. Three potential sources of error are losing product while doing the lab, not accurately measured the volume of ethanol, and not using a clean and dry graduated cylinder. Losing product while doing the lab is a given therefore it will affect our percent yield (limiting reagent will be less than calculated). Not accurately measuring out 3 mL of ethanol will most likely have a change in the end because it might have been extra product that did not get synthesized. Lastly, not using a clean and dry graduated cylinder will have a great affect in the end because the extra liquid in the graduated cylinder will change the results. All of this could have been prevented if extra steps of taken.

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Works Cited French April N., Alison Soult, Stephan Testa, Pauline Stratman , M. Meral Savas, Francois Botha, Carolyn Brock, Charles Griffith, Darla Hood, Robert Kiser, Penny O’Connor, William Plucknett, Donald Sands, Diane Vance, William Wagner. “Experiment 5: Synthesis of Aspirin.” General Chemistry Laboratory Manual Hayden-Mcneil Lab Solutions. 2019-2020. 75-82. Web. University of Kentucky. 9 March 2020.

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