Tom asked in Science & MathematicsChemistry · 1 month ago

How much of chemical B needs to be added to mixture D to result in 0.1 ppm of chemical B in the final solution? ?

We have a chemical that is dried and powdered at 96% purity which we will call chemical B. There is also a mixture of other compounds that weighs 372.88 grams that we will call mixture D. We need to mix chemical B and mixture D so there is a concentration of .1 ppm of chemical B in the finale mixture. How much of chemical B would need to be mixed to make this happen? Any help or answers are greatly appreciated, thanks.

2 Answers

  • Dr W
    Lv 7
    1 month ago

    in chemistry we teach "dimensional analysis".. or more precisely... "factor label method".  you start on the left with what you want to convert from and arrange your unit factors to convert to the right.

    see the pic... the math is entered in your calculator as

    .. 372.88 * 0.1 / 10e6 * 100 / 96 = 

    and... well... there you go. 

    Attachment image
  • 1 month ago

    0.1 PPM = 0.1/1000000

    372.88 g x 0.1/1000000 = 37.288 µg

    but the 96% purity means we need

    37.288 µg / 0.96 = 38.842 µg

    but 0.1 PPM has only 1 digit of resolution (otherwise it would be, eg, 0.100 PPM), so the correct answer is 40 µg

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