Percent Yield
- The percentage yield is the ratio between the actual yield and the theoretical yield multiplied by 100%. It indicates the percent of theoretical yield that was obtained from the final product in an experiment.
- The percentage yield can be calculated using the mass of the actual product obtained and the theoretical mass of the product calculated using the balanced equation of the reaction.
Percentage Yield = Mass of Actual Yield x 100%
Mass of Theoretical Yield
Theoretical Yield
- this is how much product will be synthesized in ideal conditions.
- To determine theoretical yield, multiply the amount of moles of the limiting reagent by the ratio of the limiting reagent and the synthesized product and by the molecular weight of the product.
- this is how much product was actually synthesized in the experiment.
- Example: 0.135 g acetylsalicylic acid
Practice Problem |
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In the following reaction, 0.157g of p-acetaminophenol was used to react with 0.486 g of acetic anhydride to produce acetaminophen and acetic acid. The product was purified and acetimophen was extracted. The actual mass of acetaminophen produced was 0.198 g. Determine the theoretical yield and the percent yield of isopentyl acetate. p-Aminophenol + Acetic anhydride à Acetaminophen + Acetic acid C6H7NO C4H6O3 C8H9NO2 CH3COOH Solution molar mass of p-aminophenol =109.1g/mol molar mass of acetic anhydride = 102.1 g/mol moles of p-aminophenol = mass/molar mass = 0.157g/(109.1g/mol) = 0.00144 mol moles of acetic anhydride = mass/molar mass = 0.486g/(102.1g/mol) = 0.00476 mol Theoretical Yield = moles of acetamiophen x molar mass of acetaminophen = 0.00144 mol x 151.2g/mol = 0.217 g Percent Yield = Actual Yield x 100% Theoretical Yield = 0.198g x 100 % 0.217g = 91.2 % |
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