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How to write Stoichiometric ratio of a reaction?

  1. Dec 7, 2014 #1
    Seasons' Greetings.

    I have been asked to express the reaction of H2N(CH2)3NH2 with HOOCCH2(C6H4)CH2COOH in a stoichiometric ratio.

    Would appreciate some guidance, not with the equation in particular, but the semantics of it.

    Best regards,
    wirefree
     
  2. jcsd
  3. Dec 7, 2014 #2
    Can you see what functionality there is in your starting materials that will undergo the reaction?
     
  4. Dec 7, 2014 #3

    Borek

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    Staff: Mentor

    Basically they ask to write reaction equation (that's where the sjb hint comes handy) and to write ratio of the coefficients. For example stoichiometric ratio of KOH to H2SO4 is 2:1 (assuming full neutralization is the reaction that is the most obvious one).
     
  5. Dec 7, 2014 #4
    I'm half-way there:

    For the two compounds, the reaction produces 2 molecules of H2O and NH(CH2)3NHCOCH2(C6H4)CH2CO

    Just whose ratio is needed?

    Thank you for your guidance,
    wirefree
     
  6. Dec 7, 2014 #5

    Borek

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    Staff: Mentor

    Ratio of reacting compounds.
     
  7. Dec 8, 2014 #6

    epenguin

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    Gold Member

    Er, the products of that reaction can themselves undergo the same reaction so there are many products, a mixture of similar things, I don't remember whether this is a common polymer (or rather "copolymer"), obviously the average ratio of the two things in them is 1:1 or close. Seems more a question of pedantic terminology than substance.
     
    Last edited: Dec 8, 2014
  8. Dec 8, 2014 #7
    I tried 1:1 but it got marked in the red.

    What else can I try?
     
  9. Dec 8, 2014 #8

    Borek

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    Staff: Mentor

    Sorry, this is more about a mind reading (what the question author had on mind) than about chemistry.

    You have a diamine and a dicarboxylic acid. They can react producing a salt - and they will react 1:1, or 1:2, or 2:1, depending on the ratio of substances mixed. They can react producing amide - again, several ratios are possible, but in the case of long chain being produced (polyamide) stoichiometric ratio is 1:1.

    I don't see any better answer than 1:1 and I have no idea what they expect.
     
  10. Dec 8, 2014 #9
    Many thanks to all who attempted to address my concerns (& mind-reading the author).

    For your reference, the question is part of edX.org's MITx: 3.091x Introduction to Solid State Chemistry course.

    Best regards,
    wirefree
     
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