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Homework Help: General Chemistry-HELP

  1. Aug 7, 2011 #1
    1. The problem statement, all variables and given/known data

    Calculate the equilibrium constant if you are given gibbs energy for the following molecules

    How many moles of NH4Cl must be added to 1.0L of 0.10M NH3 to make a buffer whose pH is 9.0?

    2. Relevant equations
    Henderson hasselbach equation,
    delta G=RTlnK

    3. The attempt at a solution
    1) How do you calculate equilibrium constant if you don’t have the temperature to use G=RTlnK
    2) For the second half the question, I am thinking of using Henderson hasselbach equation to determine the concentration of NH4Cl. If not, how should I go about solving this question.
  2. jcsd
  3. Aug 7, 2011 #2
    Just need some help starting out with the problem
  4. Aug 9, 2011 #3
    I believe unless otherwise stated, you assume T=298.15K (standard conditions).

    I'm not familiar enough with buffer solutions to help with the rest, sorry!
  5. Aug 16, 2011 #4


    User Avatar

    Staff: Mentor

    Once you have K, Henderson-Hasselbalch is the way to go.
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