A student reacts 57g of salicylic acid with 21 mL of acetic anhydride producing 10.5g of acetyl salicylic acid. What is the percent yield of the reaction?
You need the density of the acetic anhydride.
To find the percent yield of a reaction, you need to compare the actual yield (the amount of product obtained) to the theoretical yield (the amount of product that should have been obtained according to stoichiometry).
First, let's calculate the theoretical yield of acetyl salicylic acid. We can use the balanced chemical equation for the reaction:
C7H6O3 + C4H6O3 -> C9H8O4 + C2H4O2
From the equation, we can see that the molar ratio between salicylic acid (C7H6O3) and acetyl salicylic acid (C9H8O4) is 1:1.
So, the molar mass of salicylic acid is 138.12 g/mol, and the mass given is 57g. We can calculate the number of moles of salicylic acid:
Moles of salicylic acid = mass / molar mass
Moles of salicylic acid = 57g / 138.12 g/mol ≈ 0.413 mol
Since the molar ratio between salicylic acid and acetyl salicylic acid is 1:1, the theoretical yield of acetyl salicylic acid is also 0.413 mol.
Now, let's calculate the actual yield of acetyl salicylic acid. The mass given is 10.5g.
To find the percent yield, use the following formula:
Percent yield = (actual yield / theoretical yield) * 100%
Substituting the values:
Percent yield = (10.5g / 0.413 mol) * 100% ≈ 2540%
Therefore, the percent yield of the reaction is approximately 2540%.