[mburt]

Hey guys, in need of help with another question in my textbook.

The question:

Nitric acid, HNO₃, is produced from ammonia and oxygen by the consecutive reactions:

4NH₃(g) + 5O₂(g) 4NO(g) + 6H₂0(g)

2NO(g) + O₂(g) 2NO₂(g)

3NO₂(g) + H₂0(l) 2HNO₃(aq) + NO(g)

How many grams of nitric acid can be obtained from 1.00 kg NH₃(g), if NO(g) in the third reaction is not recycled?



My attempt:

I first looked at the problem and thought it would be pretty simple, and tried the following:

g NH₃ mol NH₃ mol NO mol NO₂ mol HNO₃ g HNO₃

I assumed that just using the mole ratios for the substance that is carried on between each reaction would give you the theoretical yield of the final product... Unfortunately I ended up with:

2.47 kg HNO₃

Which obviously is impossible since the question only starts with 1.00 kg NH₃(g). I've checked for small errors like molar masses and stoichometric factors but I can't seem to find the issue.

I have a feeling that the last part of the question, "if NO(g) in the third reaction is not recycled", may be important. But unfortunately I have no idea the "recycled" part means- I've scoured my textbook and haven't really come up with anything.

Thanks a lot,

Michael

[fledarmus]

I haven't checked your math, but I assume you are worried that your product has more mass than your starting material - 2.47>1? Have you considered that ammonia isn't your only starting material?

[Dan]

2.47 kg is correct.

[mburt]

Thanks fledarmus- and yes that is what I was assuming. I see now! Thanks again, to both of you.