1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Find Limiting Reactant

  1. Feb 3, 2009 #1
    1. The problem statement, all variables and given/known data

    I have this information from a lab handout

    I have:

    .40g of NH2 = .25 mol NH2

    .58g of (CH3CO)2O = .0092 mol (CH3CO)2O

    and the reaction

    NH2 + (CH3CO)2O---> HNCOCH3 + CH3COOH

    I need to find the limiting reactant

    I know that since the only product with N on the right hand side is HNCOCH3 so ALL of its N must have come from the NH2

    I am just not sure how to "test" the reactant (CH3CO)2O ? Both products contain all of those elements?

    Any thoughts?
  2. jcsd
  3. Feb 3, 2009 #2
    Because the entire equation reacts in a 1 to 1 ratio (all stoichiometric proportions are equal) your limiting reagent is the one with the smallest number of moles.
    only 0.0092mol of (CH3CO)2O is available to react, and as the number of moles of NH2 that will react with it is in equal proportion (the 1:1 ratio), only 0.0092 of the 0.25 mol NH2 will ever react. Thus, the (CH3CO)2O is the limiting reagant

    I may have oversimplified the question, but I hope this helps!
  4. Feb 3, 2009 #3
    No, I think it it a matter of me over complicating it! Thanks!

  5. Feb 4, 2009 #4


    User Avatar

    Staff: Mentor

    What is NH2?
  6. Feb 11, 2009 #5
    I'm not sure. But I think its an amino group and that because its a cation is available to attach as a amine to carbohydrates and such.
  7. Feb 12, 2009 #6


    User Avatar

    Staff: Mentor

    Trick is, such a thing doesn't exist as a separate entity.

    My bet is that it was some kind of error, in copying or something.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook