What Is the Correct Theoretical Yield of HNO3 in This Chemistry Problem?

AI Thread Summary
The discussion focuses on a chemistry problem regarding the synthesis of nitric acid (HNO3) from nitrogen dioxide (NO2) and water (H2O). The user calculates the limiting reagent as NO2 and determines the theoretical yield of HNO3 to be 24.001 g. However, there is confusion regarding the stoichiometry of the reaction, specifically the number of moles of H2O required. Participants suggest that the book may contain a typo, as the answer provided does not align with the question about the theoretical yield of HNO3. The overall conclusion of the user's calculations is deemed correct despite the noted discrepancies.
ducmod
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Homework Statement


Hello!
I would be grateful for your help on finding my mistake - somehow my answers are
wrong compared to the answer from the book.
Here is the exercise from a paragraph on gases (cumulative gas law, basics):

Consider the reaction for the synthesis of nitric acid:
3NO2 + H2O = 2HNO3 + NO
(a) If 12.8 L of NO2 measured at STP, is allowed
to react with 14.9 g of water, find the limiting
reagent and the theoretical yield of HNO3 in
grams.

Here is my solution:

1 mole of gas at STP = 22.4 L; 12.8 L gives 0.5714 moles of NO2
1 mole of H2O = 18.016 g; 14.9 g = 0.827 moles of H2O

The limiting reagent is NO2, because
3 moles NO2 + 2 moles of H2O
0.5714 moles NO2 requires only 0.381 moles of H2O, but we have 0.827 moles of H2O

1 mole of NO2 = 46.007 g
0.5714 moles of NO2 = 26.288 g
Theoretical yield of HNO3:
3 moles of NO2 = 2 moles of HNO3
0.5714 moles of NO2 = 0.3809 moles of HNO3

1 mole of HNO3 = 63.008
0.3809 moles of HNO3 = 24.001 g

Thank you!
 
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ducmod said:
3 moles NO2 + 2 moles of H2O
Why 2 moles of H2O?
The conclusion is still right.

Looks right.
I don't think you have to work with decimal numbers of molar masses, they are very close to integers for the involved elements.
 
There is the mistake mfb already pointed out, but it doesn't influence the final answer.

What is the answer given in the book?
 
mfb said:
Why 2 moles of H2O?
The conclusion is still right.

Looks right.
I don't think you have to work with decimal numbers of molar masses, they are very close to integers for the involved elements.
Thank you! Sorry, yes, only one mole of H2O.
 
Borek said:
There is the mistake mfb already pointed out, but it doesn't influence the final answer.

What is the answer given in the book?
I think the problem was in the question - there is some typo in the book, because exercise is asking about theoretical yield of HNO3,
while the book gives answer on grams of NO2
 
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