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Homework Help: PH question, I really don't get this!

  1. Dec 5, 2006 #1
    1. The problem statement, all variables and given/known data
    What is the [H3O+] of acid rain with a pH of 4.23?


    2. Relevant equations
    pH = -log[H30+]
    pOH = -log[OH-]
    pH + pOH = 14


    3. The attempt at a solution

    the four possible choices are
    a. 1.7 x 10^-10
    b. 5.8 x 10^-5
    c. 2.3 x 10^-4
    d. 1.7 x 10^5
     
  2. jcsd
  3. Dec 5, 2006 #2
    You are given the pH and need to calculate the concentration of the [tex]H_{3}O^+[/tex] ions. Which equation should you use?
     
  4. Dec 5, 2006 #3
    I know I have to use the first one but I don't know how to do the reverse of it
     
  5. Dec 5, 2006 #4
    Since pH = -log[H30+] or pH = -log[H+]
    H3O+/H+ = 10^(-pH)
     
    Last edited: Dec 5, 2006
  6. Dec 5, 2006 #5
    But I dont get how to plug it in on my calculator
     
  7. Dec 6, 2006 #6
    10^(-pH)
    10 to the -pH power.
     
  8. Dec 6, 2006 #7
    Oh okay I got the answer thank you so much!
     
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