C4H6O3+C7H6O3?C9H8O4+C2H4O2

Question

Aspirin can be made in the laboratory by reacting acetic anhydride (C4H6O3) with salicylic acid (C7H6O3) to form aspirin (C9H8O4) and acetic acid (C2H4O2). The balanced equation is:
C4H6O3+C7H6O3→C9H8O4+C2H4O2.In a laboratory synthesis, a student begins with 5.00 mL of acetic anhydride (density = 1.08 g / mL) and 2.08 g of salicylic acid. Once the reaction is complete, the student collects 2.47g of aspirin.

 

I need to find the theoretical yield and the percent yield. I know that the Limiting reactant is C7H6O3

Answer 1

You have to set up a stoichiometric expression to determine how much salicylic acid (SA) you should have made.

Information you need to complete this....

1) Molar mass of SA

C: (12.01g) x 7= 84.07g
H: (1.01g) x 6= 6.06g
O: (16.00g) x 3= 48.00
--------------------------------------...
138.13g/mol salicylic acid

 

2) Molar mass of Aspirin

C: (12.01g) x 9= 108.09 g
H: (1.01g) x 8= 8.08 g
O: (16.00g) x 4= 64.00 g 
--------------------------------------...
180.17g/mol aspirin

 

 

Since SA is your limiting reagent, the volume of Acetic anhydride is not relevant. Set up a dimensional analysis, utilizing units and formulas. (Remember to use the correct # of decimal points that your teacher requests and follow significant digit rules)

 

2.08g SA x 1 mol SA        x 1 mole aspirin  x   180.17 g aspirin

                 138.13 g SA      1 mole SA             1 mole aspirin

 

Multiply across the top and divide by the bottom

 

Answer = theoretical yield

 

 

 

Then to calculate percent yield

Take your actual yield (2.47 g) divide by theoretical yield from above (_____) and multiply by 100 to get a percent.