I need some help with calculating percent yield and percent purity of aspirin.

Here's my data (questions follow):

Mass of salicylic acid.., 2.0 g
Volume of acetic anhydride.., 5 mL
Mass of watch glass.., 22.10 g
Mass of aspirin and watch glass.., 28.01 g
Mass of aspirin.., 5.91 g

Mass of aspirin.., 0.34 g
Concentration of NaOH.., 0.1 M
Initial buret reading.., 0 mL
Final buret reading.., 15.8 mL
Volume of NaOH used.., 15.8 mL
Number of moles of NaOH required.., 1.60 x10^-3 mol

1. Calculate your mass percent yield of aspirin.

(actual yield, g/theoretical yield, g) x 100

Not sure what numbers I'd use here...

2. Calculate the percent purity of your aspirin.

(mass of aspirin, g (titration)/mass of aspirin, g (synthesis)) x 100

(0.34 g/5.91 g) x 100 = 5.8%

I'm pretty sure that's right, but not positive.

I'm not sure either but here is some discussion.
From synthesis:
Convert mass salicylic acid to mols.

Convert mols salicylic acid to mols aspirin know that 1 mol salicylic acid should produce 1 mol aspirin.

Convert mols aspirin to grams aspirin from mols aspirin x molar mass aspirin = g aspirin theoretical yield.

According to my calculations, 2.0 g salicylic acid should produce about 2.6 g aspirin. According to your data, you produced 5.91 g and that is WAY over what you should have obtained. Perhaps you didn't dry the aspirin on the watch glass very well before weighing.

If all of the synthesis part is as I understand it, then actual yield is 5.91 (I GUESS we are assuming all of that is aspirin) and theoretical yield is 2.61 and that makes for greater than 200% yield.

For #2, the answer is more straight forward. The only complaint I have here is that the 0.34g is labeled as mass aspirin when in reality it is the mass of the SAMPLE. From below you see mass of aspirin in that sample is less than that).
mols NaOH = M x L = 0.1 x 0.00158 = ??
mols aspirin = the same number.
multiply mols aspirin x molar mass aspirin to obtain grams aspirin. I found 0.284 g (that's out of the 0.34 g sample taken for analysis). That divided by 0.34 (that is the mass of sample taken for analysis) x 100 = %purity and I found about 84% purity. Of course the immediate question is, "What is rest of it?" Since you have over 200% yield, then we might expect SOME of the sample to be impure aspirin BUT there is a discrepancy even in these numbers for 84% yield means you have an extra 16% something else there but the theoretical yield is so much MORE than that. There is another 185% somewhere.
I suspect the original sample was not dried thoroughly AND I suspect that some time elapsed between the preparation of the sample and the determination of purity which gave it some time to air dry more.
I hope this gets you started.

Mass percent yield is found first by getting your experimental yield in grams by multiplying grams of SA sample used, times the molar mass of SA, times the mole ratio of SA and aspirin, times the molar mass of aspirin. Then divide the experimental (actual) yield by the theoretical yield, then multiply by 100 to get the mass percent yield.

  1. 👍
  2. 👎
  3. 👁
  1. ogltbwm rnvgzbjlk sitmp ztoqsc wdbu pfgscdz kxaqzt

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions


    Yield to call Six years ago, the Singleton Company issued 20-year bonds with a 14 percent annual coupon rate at their $1,000 par value. The bonds had a 9 percent call premium, with 5 years of call protection. Today, Singleton

  2. DESPERATE NEED OF HELP--Chemistry, almost done

    Calculating Yield--need some help finishing problem. Almost done, just need help one ONE step, please help!!? Well we did a lab on limiting reagent/reactants. The balanced equation is Sr(NO3)2 + 2KIO3 --> Sr(IO3)2 + 2KNO3 Mols of

  3. 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

  4. Finance

    Your company sponsors a 401(k) plan into which you deposit 12 percent of your $60,000 annual income. Your company matches 50 percent of the first 5 percent of your earnings. You expect the fund to yield 10 percent next year. If

  1. Chemistry

    Question Given the equation: 4 Fe(s) + 3 O2(g) ? 2 Fe2O3(s), what is the theoretical yield of Fe2O3 from the reaction of 4.86 g Fe with excess O2? b. If 6.76 g Fe2O3 are actually obtained from 4.86 g Fe, what is the percent yield?

  2. Chemistry Pretest

    Fe can be prepared as 2 Al + Fe2O3 ----> 2 Fe + Al2O3. Suppose that 0.450 moles of Fe2O3 are reacted with an excess of Al. Suppose that 43.6 grams of Fe are obtained. What is the percent yield of Fe? a) 16.2% b) 60.7% c) 86.7% d)


    Nearly ________ of the heat produced in the body is the result of muscle contraction. A. 55 percent B. 65 percent C. 75 percent D. 85 percent D?

  4. 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

  1. chemistry

    1. Chlorobenzene, C6H5Cl, is used in the production of chemicals such as aspirin and dyes. One way that chlorobenzene is prepared is by reacting benzene, C6H6, with chlorine gas according to the following BALANCED equation. C6H6

  2. alg 1

    Find the percent error in calculating the volume of the prism. V=(bw)(h) v=11 x 8 (7) V=616 my choices were: 19% 10% 119% 83% I'm not sure what it means to find the percent error. Please explain. Thanks.

  3. Chemistry

    Consider the following reaction: 2 SO2 (g) + O2 (g)----> 2 SO3 (g) If 285.3 mL of SO2 is allowed to react with 158.9 mL of O2 (both measured at 315 K and 50.0 mmHg), what is the limiting reactant and theoretical yield of SO3 in

  4. 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? If so, how do we find the mass of acetic acid in this experiment volume of acetic

You can view more similar questions or ask a new question.