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elisichi

I am studying the Haber process, and it says that to obtain nitrogen, hydrogen is burned in the air, so that it combines with oxygen and leaves nitrogen. Could anybody help me elaborate a balanced equation for this statement?

  • one year ago
  • one year ago

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  1. EmmaH
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    wow this is out of my league i am only ok at bio ....really sorry

    • one year ago
  2. elisichi
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    Its okay :) Dont worry about it!

    • one year ago
  3. stewie
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    do you have answer chooses?

    • one year ago
  4. elisichi
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    no :(

    • one year ago
  5. stewie
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    alright ill try and find the answer

    • one year ago
  6. stewie
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    do you have notes on this i can look at

    • one year ago
  7. elisichi
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    no, nothing really... because its an essay we are supossed to write

    • one year ago
  8. Carl_Pham
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    \[2 {\rm H}_2(g) + {\rm O}_2(g) \rightarrow 2 {\rm H}_2{\rm O}\] However, if it matters, I believe this statement is wrong, if you are talking about current industrial processes. Hydrogen is fairly expensive to produce, and the normal way in which nitrogen is extracted from air industrially is to cool the air. The other major components will all condense (to liquid or solid) before nitrogen -- water will freeze at 0C, CO2 will condense at 195K, oxygen will liquify at 90K, argon will liquify at 84K. Nitrogen itself does not liquify until 77K. Of course, in the laboratory setting it might be easier to proceed by burning H2. Or maybe you are referring to historical processes.

    • one year ago
  9. Carl_Pham
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    Sorry I left out the final (g) on the H2O in the chemical equation. You'd also have to do cool the reaction mixture after the combustion if you wanted to remove the water vapor.

    • one year ago
  10. elisichi
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    Yes I have seen that equation, but I wanted to include nitrogen somewhat because its part of the air, so that it is shown in the equation.. but i dont know how to do that

    • one year ago
  11. elisichi
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    like I don't want the ionic equation, but the 'whole thing' if you know what I mean :D

    • one year ago
  12. Carl_Pham
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    The nitrogen isn't reacting, so it isn't part of the equation. You can certainly add it to both sides if you like:\[{\rm N_2}(g) + 2 {\rm H}_2(g) + {\rm O}_2(g) \rightarrow 2 {\rm H}_2{\rm O}(g) + {\rm N}_2(g)\] But that really doesn't tell you anything interesting.

    • one year ago
  13. elisichi
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    Hmm, so you think it's better if I write the first one and then explain that nitrogen is included as well rather than writing the second one?

    • one year ago
  14. Carl_Pham
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    What are you trying to say? What's the point you're trying to make? If what you're sayiing is that burning H2 in air will remove the oxygen, the first equation is sufficient. You should also say something about the stoichiometry, pointing out that the equation tells you that you need 2 volumes of H2 for every volume of O2 you want to remove, e.g. to remove 1L of O2 you'd need to burn 2L of H2. To be 100% sure you get all the O2, you'd probably want to include an excess of H2, in fact.

    • one year ago
  15. Carl_Pham
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    I'm also curious: you say "it says" that H2 is burned to remove O2 from air. Can you tell me what "it" is? That is, what source is making this statement? A textbook? Online source? Article? I'd be very interested in knowing the specific source.

    • one year ago
  16. elisichi
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    Never mind, never mind. I get it. My mind was just doing something weird to me. hahah! Of course I dont need the nitrogen, cause it's pointless since it's not showing anything. Thank you soo much :D

    • one year ago
  17. Carl_Pham
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    So can you tell me what source says N2 is produced by burning H2 in air?

    • one year ago
  18. elisichi
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    It's a website. We are to write an essay and I've been researching

    • one year ago
  19. elisichi
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    Why?

    • one year ago
  20. Carl_Pham
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    I ask because I believe that statement is likely to be in error, and it's important to know what sources might be spreading error. The profession of chemistry instruction needs to police itself.

    • one year ago
  21. elisichi
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    I don't believe it's an error. In fact, it makes sense. For the Haber process, you need nitrogen and hydrogen. The air is made of mostly nitrogen and oxygen. By burning hydrogen in the air, hydrogen and oxygen combine together. And it is, therefore, easier to extract nitrogen, so it can be later on used for this process. I didn't mean the reaction produced nitrogen literally. I didn't express myself correctly there. So blame me not the source.

    • one year ago
  22. Carl_Pham
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    No, sorry, that's not correct. Or rather, you certainly COULD do it that way, but that's not in fact how it's actually done. As I said above, nitrogen is extracted from air by what's called fractional liquefaction -- you cool the air until everything except the nitrogen condenses. A very good canonical print reference for industrial processes is "Survey of Industrial Chemistry" by Philip J. Chenier. Has every chemical you could want, with details of how it's produced and used. Your library will have a copy.

    • one year ago
  23. elisichi
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    Are you a 100% sure? Because, it's from the BBC... http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/chemreac/energychangesrev3.shtml

    • one year ago
  24. Carl_Pham
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    Yes, I'm sure. I'm looking at the site now. You're right that it would be a little surprising to find the BBC writing nonsense, but it could happen. Let me have a look. Thank you very much for supplying the link. Let me see if I can find you a good authoritative source. I'll also look over that BBC site to be sure they haven't said anything else that's weird.

    • one year ago
  25. elisichi
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    Exactly, I doubt the BBC would write incorrect stuff, especially considering that it's Bitesize, a site that thousands of students use as a learning resource.

    • one year ago
  26. Carl_Pham
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    Sure, but it could happen. The problem here is that this is contradicted by even more authoratative sources -- for example, the one I gave you, which is a standard textbook in industrial chemistry written by a chemical engineering professor at the University of Wisconsin, and used all over the country to teach chemical engineers. Which is more likely, do you think? That a standard chemical engineering textbook is wrong (and has been for decades), or that whoever wrote the BBC website made a booboo?

    • one year ago
  27. elisichi
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    Are you sure that book is on the Haber process? and not some other process? Of course, I agree it's possible. The internet is full of unreliable bullpellet these days.

    • one year ago
  28. Carl_Pham
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    Tell you what: google "Haber process" or "industrial production of ammonia" and see if you can find a single other source that suggests the nitrogen comes from burning H2 in air. So far the BBC is the only one I can find. I'm still looking...

    • one year ago
  29. elisichi
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    I was actually doing the exact same thing right now. Great minds think alike.

    • one year ago
  30. elisichi
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    I found another source that agrees with the BBC. http://www.warwickshire-ecosiht.org.uk/subject/science/Haber_process_000.htm

    • one year ago
  31. elisichi
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    Yet, I cannot guarantee it's very reliable...

    • one year ago
  32. elisichi
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    Anyway, you deserve a medal.

    • one year ago
  33. Carl_Pham
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    It's exactly the same image. These sources clearly copied from each other, but which came first is unclear.

    • one year ago
  34. Carl_Pham
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    OK, I think it might be right at least in Europe, at least some of the time. Here's an extremely authoritative source: http://www.ocinitrogen.com/Media%20Library/Ammonia%20process%20-%20BAT%20Production%20of%20ammonia%20(2000)%20-%20Brochure.pdf That is a brochure produced by the European Fertilizer Manufacturer's Association, and made available on the website of a European company (OCINitrogen) that actually manufacturers ammonia industrially. So there's no doubt about that. The brochure is fairly technical, but they describe two processes for making ammonia. One proceeds basically according to the same diagram on the BBC site, in which as part of the steam reforming part of making H2 from methane, some of the H2 produced is burned and removes the O2 from the air, which is then passed straight on to the ammonia synthesis stage. There is another process that uses N2, presumably supplied by liquefaction of air. So at least in Europe, at least for one major process, the BBC site is right and I and the standard reference textbook is wrong. Amazing! This has been very educational. It may be that the process generally used in the United States differs, of course. There are distinctions based on what resources are convenient, and those vary from country to country.

    • one year ago
  35. elisichi
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    Ok, that makes sense! I can write about that on my essay! Thank you so much for taking your time. You don't know how much I truly appreciate it. I'd give you 1000 medals if I could.

    • one year ago
  36. Carl_Pham
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    The pleasure is mine. This has been a fascinating exercise. I found a few more references that suggest that some plants use the burning of some of the H2 to make the N2, and others use N2 from liquefaction of air. I can't find out which is more often used, nor what determines which is preferred. Good luck.

    • one year ago
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