# chemistry - synthesis of aspirin

posted by .

This is an experiment for a synthesis of aspirin lab

mass of salicylic acid = 2.005 g

mass of acetic acid = ?

moles of acetic acid = ?

volume of acetic anhydride = 4 ml

mass of acetic anhydride (Use 1.08 g/ml for the liquid density) = (1.08 g/ml)
(4 ml) = 4.32 g

moles of acetic anhydride (C4H6O3; molar mass = 102 g) = 4.32 g / 102 g = .042 mol

mass of filter paper = .196 g

mass of filter paper plus aspirin = 2.386 g

mass of weighing tray = 1.900 g

mass of filter paper, aspirin, and weighing tray = 4.286 g

mass of aspirin = 2.19 g

moles of aspirin (C9H8O4; molar mass = 180 g) = 2.19 g / 180 g = .012 mol

I understand now how to calculate the theoretical, actual and percent yield of aspirin. But I don't know how to calculate the mass of the acetic acid.

thank you for any help

• chemistry - synthesis of aspirin -

I checked your values for mols aspirin and it looks good except I would carry it out one more place. You have 3 significant figures in all of the other numbers (if the 4 mL is 4.00 mL); therefore, you can have 3 in the 0.012 number. Same for mols acetic anhydride; again I'm assuming the 4 mL is 4.00 mL.
Did you have any water? Are you supposed to assume there was no water present in the calculation of the mass acetic acid?
If you had no H2O present then salicylic acid is the limiting reagent and it will produce (theoretically) that many mols of acetic acid.
sal acid + acetic anhydride =>aspirin + acetic acid and everything is 1:1:1:1.
If aspirin was about 80% yield, the acetic acid should be about 80% yield also.

• chemistry - synthesis of aspirin -

ok therefore, the mass of the aspirin is equal to the mass of the acetic acid since the ratio is 1:1. Right?

• chemistry - synthesis of aspirin -

wait, i misunderstand. You stated that if there's no H2O present then salicylic acid is the limiting reagent. Therefore salicylic acid number of moles is the same as the number of moles of acetic acid???? If this is so, then the mass of acetic acid would also be 2.005 g, right?

• chemistry - synthesis of aspirin -

No. Mass of acetic acid = mols acetic acid x molar mass acetic acid and that is the theoretical yield of acetic acid in grams.
I don't know the exact instructions you have but if I were asked to calculate grams acetic acid produced I would do as above then multiply by the percent yield for the aspirin to arrive at g acetic acid I would expect to be produced. My assumption is that percent yield for aspirin and percent yield for acetic acid is the same.

## Similar Questions

1. ### chemistry

I need some help with calculating percent yield and percent purity of aspirin. Here's my data (questions follow): SYNTHESIS Mass of salicylic acid.., 2.0 g Volume of acetic anhydride.., 5 mL Mass of watch glass.., 22.10 g Mass of aspirin …
2. ### AP Chemistry

Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation is given below. C7H6O3 + C4H6O3 C9H8O4 + HC2H3O2 (a) What mass of acetic anhydride is needed to completely consume …
3. ### chemistry lab

if you find salicylic acid or acetic anhydride in your aspirin synthesis product why are they there?
4. ### chemistry - synthesis of aspirin

I wanted to calculate the theoretical and actual yield of aspirin. mass of salicylic acid = 2.005 g But isn't salicylic acid differ. from acetic acid?
5. ### chemistry - synthesis of aspirin

wanted to calculate the theoretical and actual yield of aspirin. mass of salicylic acid = 2.005 g But isn't salicylic acid differ. from acetic acid?
6. ### Chemistry

If 0.150 moles of salicylic acid and execs acetic anhydride are used during a synthesis of aspirin, how many grams of aspirin will be obtained if the reaction gives a 38% yield?
7. ### chem

Aspirin, C9H8O4, is produced from salicylic acid, C7H6O3, and acetic anhydride, C4H6O3: C7H6O3 + C4H6O3 --> C9H8O4 + HC2H3O2 a. How much salicylic acid is required to produce 1.5 x 10^2 kg of aspirin, assuming that all of the salicylic …
8. ### Chemistry

Aspirin is prepared by heating salicylic acid, C7H6O3, with acetic anhydride, C4H603. The other product produced is acetic acid, C2H402. C7H6O3+C4H6)3->C9H8O4+C2H4O2 What is the theoretical yield in grams of aspirin, C9H8O4, when …
9. ### chemistry (Pls Bob check for me)

Aspirin c9h8oh molar mass = 180.1g/mol can be prepared by the reaction of salicylic acid c7h603 molar mass = 13801 g/mol with acetic anhydride c6h603, according to the following equation. A chemist starts with 2 gram of salicylic acid …
10. ### chem

A chemist is commissioned to produce twenty pallets of aspirin: C7H6O3 (salicylic acid) + C4H6O3 (acetic anhydride) → C9H8O4 (aspirin) +C2H4O2 (acetic acid) Given a bottle contains 500 tablets (each containing 325 mg of aspirin). …

More Similar Questions