1. Not finding help here? Sign up for a free 30min 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!

Ka estimate

  1. Nov 4, 2008 #1
    1. The problem statement, all variables and given/known data
    Estimate the Ka the using the assumption that the color change can be seen by our eyes when [ln-]/[Hln] = 1/10
    to see the acid form or [ln-]/[Hln] = 10/1 to see the color associated with the base.
    Use these numbers with your measured [H+] to calculate a Ka for each indicator you measured.

    2. Relevant equations
    acid-base base-acid H+
    Phenolphthalein 8.7 7.4 8.91E-09

    I got the hydronium concentration by taking taking the average of the ph values and doing 10^-ph. How do i get the ka estimates?

    Do i set up the equation like this: ka = 1/[H+] or something like this?
     
  2. jcsd
  3. Nov 4, 2008 #2

    Borek

    User Avatar

    Staff: Mentor

    Describe the experiment that you did. I am almost sure you have not posted all information that you have.
     
    Last edited: Nov 4, 2008
  4. Nov 4, 2008 #3
    [​IMG]
     
  5. Nov 4, 2008 #4

    Borek

    User Avatar

    Staff: Mentor

  6. Nov 4, 2008 #5
    ya i know that the phs are wrong. The bromophenol blue was really off. When calculating the H+ concentration, i only used 4.2, not 9.3.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Ka estimate
  1. Calculating Ka (Replies: 2)

  2. Finding ph from Ka (Replies: 2)

Loading...