Solving Antilog MCAT Questions Without A Calculator

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MCAT math tutorial video on anti logsThis video picks up from MCAT Math Part 8 – Logs and Negative Logs showing you how to solve questions where the log value is provided. Instead you’re asked to solve for the anti-log value in questions relating to ion concentration and Ka values.

Anti-logs, just like logarithms, are difficult to calculation without a calculator UNLESS you know the tricks and shortcuts to apply. Watch the video below to learn how to tackle these MCAT style questions.

Anti-logs Without A Calculator

(click to watch on YouTube or click for Video Transcript)

MCAT Style Question Covered In This Video:

Chemistry Buffers/Ka Question: Find the ka of an acid whose buffer has a pH of 4.19 in a solution containing equal moles of acid and conjugate base.

See Previous Video – Logarithms and Negative Logs

Need additional MCAT style math practice? Click HERE for my FREE MCAT Math Quiz

This is Video #9 in my MCAT Math Without A Calculator tutorial series. Click HERE for the entire series


  1. How did you decide that the answer was # x 10^-5 rather than # x 10^-4? Because the range for the pKa was between 4 and 5, so what made you conclude that the pKa was closer to 5 than to 4?

  2. michael c says:

    I think you may have misspoke… 6.46 is closer to 5 than to 8 🙂 These videos are very helpful!!

  3. At 3:48, how did you just concluded that 4.19 will give you a number (#) x 10^-5?

    I know that is what the answer ends up being, but how did you just jump to that?

  4. Samia Jaffar says:

    Hi Leah, I am confused as to what the .1 .3, and .5 values refer to? is that the value of the pKA?

  5. shantanu says:

    what is the value of 10 raised to -0.2????

    • Leah4sci says:

      For the MCAT simply estimate that it’s between 10^0 and 10^-1. That’s between 1 and 0.1

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