Question

A student adds 200.0g of C7H6O3 to an excess of C4H6O3, this produces C9H8O4 and C2H4O2. Calculate the percent yield if 231 g of aspirin (C9H8O4) is produced in an experiment.

Answer 1

Answer: Percent yield = 88%

Explanation:

Given data:

Mass of C₇H₆O₃ = 200.0 g

Actual yield of aspirin = 231 g

Percent yield  = ?

Solution:

Chemical equation:

C₇H₆O₃  + C₄H₆O₃      →       C₉H₈O₄ + C₂H₄O₂

Number of  moles of aspirin:

Number of moles = mass/molar mass

Number of moles = 200.0 g/ 138.12 g/mol

Number of moles =  1.45 mol

Now we will compare the moles of aspirin with C₇H₆O₃.

                         C₇H₆O₃           :           C₉H₈O₄

                              1                 :               1

                           1.45              :             1.45

Theoretical yield of aspirin:

Mass = number of moles × molar mass

Mass = 1.45 g × 180.158 g/mol

Mass = 261.23 g

Percent yield:

Percent yield =( actual yield / theoretical yield )× 100

Percent yield =  (231 g/ 261.23 g)× 100

Percent yield = 0.88 × 100

Percent yield = 88%

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