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How did I get a greater than 100% recovery of benzoic acid?

To quickly summarize, the lab dealt with isolating benzoic acid from a mixture via chemically active extraction. The mixture consisted of cellulose, methyl orange and of course the benzoic acid.

We had to weigh about 4.0 g of the mixture. I weighed 4.08g. I did the lab, and after letting the benzoic acid dry I obtained 10.91 grams of benzoic acid? How can this be?

Because of this I am trying to figure out if my calculations for the percent yield is correct. Isn't the percent yield just the mass of the actual product divided by the mass of expected product?

Solution Preview

You are definitely correct about not being able to get more benzoic acid than you had mass of starting mixture. You are using the right equation, too. According to what you correctly stated, you would be looking at approximately a 250 % recovery (and ...

Solution Summary

The solution outlines possible reasons for obtaining a greater than 100 % recovery for an extracted compound.