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CHEM Equilibrium constant help !

  1. Apr 6, 2009 #1
    1. The problem statement, all variables and given/known data
    2NS(g) + 2H2(g)<---> N2(g) + 2H2S(g) @ equilibrium in a 4.L flask @ 25o
    C. 2.5 mol of eah component initially is put into the flask. At equilibrium, 2.5 mol of NS is present. what is Kc for the rxn at this temp??

    2. Relevant equations

    Kc=[products]/[reactants]
    M=moles/L
    initial - change = equilibrium
    3. The attempt at a solution

    Kc=1 i thought the answer is a little odd.... because the intital and equilbrium is 2.5 moles for NS so I'm unsure about my answer... please help! geatly appreciates all help! thank you in advance.
    if my answer is wrong...can someone show me how to do it i know how to set up Kc, but im troubled when finding the intial, change and equilibrium of each components.
     
  2. jcsd
  3. Apr 6, 2009 #2

    Borek

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    Staff: Mentor

    First of all - can you write correct reaction quotient?
     
  4. Apr 6, 2009 #3
    kc=[N2][HS]2/ [NS]2[H2]2
     
  5. Apr 6, 2009 #4

    Borek

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    Staff: Mentor

    OK (let's assume HS is just a typo :wink:).

    Question is a little bit strange, as it seems amount of NS have not changed. But that's not your problem - if amount of NS have not changed, there were no reaction, thus initial amount of other reactants have not changed either. Can you calculate what are their concentrations?

    PS PLease check - just in case - if you have copied question exactly as it was written.
     
  6. Apr 6, 2009 #5
    hehe yea i did make a typo..sorry
    their initial concentration is .625 M. I took 2.5 n divided that by 4.0 L
    2NS9g0 +2H2(g<-----> N2g) + 2H2S(g) at equilibrium in a 4.0L flask at 25oC. suppose 2.5 mol of each component initially is put into the flask. At equilibrium, 2.5 mol of NO is present. What is Kc for the reaction at this temperature?
     
  7. Apr 6, 2009 #6

    Borek

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    Staff: Mentor

    Sigh...

    Put know concentrations into reaction quotient.
     
  8. Apr 6, 2009 #7
    kc is still 1
     
  9. Apr 6, 2009 #8
    nvm its 1.6
     
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