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Thread: Logarithmic scale for pH: how many times more acid is pH 5.2 than pH 6.5?

  1. #1

    Logarithmic scale for pH: how many times more acid is pH 5.2 than pH 6.5?

    Hi, my question is about the logarithmic scale used for pH.
    I know pH 5 is 10 times more acid than pH 6 and 100 times more acid than pH 7.
    What about fractions of pH values?
    Is pH 4.5 actually 50 times more acid than ph 6?
    I need to know...how many times more acid is pH 5.2 than pH 6.5?
    I would really appreciate any help on this.
    Thank you.

  2. #2
    Elite Member mmm4444bot's Avatar
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    Check out this short example, and let us know if you have any more questions.
    "English is the most ambiguous language in the world." ~ Yours Truly, 1969

  3. #3

    Logarithmic scale for pH 2

    Quote Originally Posted by mmm4444bot View Post
    Check out this short example, and let us know if you have any more questions.
    Hi, thank you so much for the reply.
    The equation makes sense. When I do the example I get the same answer. Also when I use whole integers I get the correct answer (pH5 is 10 times more acid than ph6) but when I tried my numbers comparing pH 5.2 and 6.5, it doesn't seem to work.
    See below:
    10-5.2 = 6.31 x 10-6
    10-6.5 = 3.16 x 10-7 = 31.6 x 10-6

    6.31/31.6 = 0.1997

    I don't know what I'm doing wrong (feeling kind of stupid). pH 5.2 should be about 50 times more acid than 6.5 right (pH5 is 100 x more acid than pH7)??

  4. #4
    Elite Member stapel's Avatar
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    Cool

    Quote Originally Posted by tambaqui View Post
    10-5.2 = 6.31 x 10-6
    10-6.5 = 3.16 x 10-7 = 31.6 x 10-6
    3.16 * 10^(-7) = 0.000000316

    31.6 * 10^(-6) = 0.00000316

    They're not equal. Did you perhaps mean to convert as follows?

    6.31 * 10^(-6) = 63.1 * 10^(-7)


  5. #5

    Logarithmic scale for pH: how many times more acid is pH 5.2 than 6.5? answer: 19.97

    Quote Originally Posted by stapel View Post
    3.16 * 10^(-7) = 0.000000316

    31.6 * 10^(-6) = 0.00000316

    They're not equal. Did you perhaps mean to convert as follows?

    6.31 * 10^(-6) = 63.1 * 10^(-7)

    thank you, I got 19.97 for an answer.

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