Final answer:
To calculate the overall % yield of aspirin from methyl salicylate, calculate the % yield for each step by dividing the actual yield by the theoretical yield and multiply by 100. The overall yield is the product of the yields from each step. Use the molar mass of aspirin, C9H8O4, which is 180.15 g/mol, to find the theoretical yield from reactant amounts.
Step-by-step explanation:
To calculate the overall % yield of aspirin from methyl salicylate in a two-step synthesis, you need the theoretical and actual yields for both reactions. The theoretical yield is the maximum amount of product expected from the stoichiometry of the balanced chemical equation, given the limiting reactant. The actual yield is the measured amount of product obtained from the experiment. The % yield for each step is calculated using the formula:
% Yield = (actual yield / theoretical yield) x 100%
For a multi-step synthesis, like converting methyl salicylate to aspirin, the overall % yield is the product of the individual yields of each step:
Overall % Yield = (% yield of step 1) x (% yield of step 2)
Using the example provided where 12.03 g of aspirin is isolated, if this is from the first reaction and 12.66 g of C7H6O3 were reacted, then:
% Yield of step 1 = (12.03 g / theoretical yield from 12.66 g of C7H6O3) x 100%
To get the theoretical yield from the molecular formula and mass of aspirin (C9H8O4), calculate the molar mass by summing up the atomic masses for the atoms, resulting in 180.15 g/mol. Using given moles or mass of reactants and the balanced equation, determine the theoretical yield of aspirin. With both the actual (0.7688 g) and theoretical yields, you can calculate the % yield of the final product.