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Major school task problem

  1. May 26, 2004 #1
    I am preparing an experiment to find out what the mass percentage of NaOH in Plumbo is and someone has allready suggested using titration, but that did not seem logic. I know how to calculate the mass percentage, but I and my group were given a sheet of paper with a problem which we are to solve. We are to make an suggestion for how to solve this problem, and I am in doubt whether this is very simple or very complicated.

  2. jcsd
  3. May 27, 2004 #2


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    Can you state the problem exactly as it appears on your sheet of paper.
  4. May 28, 2004 #3
    Titrate. Simple.

    I'm guessing Plumbo is a liquid?

    Do you have access to phenolphtalein or a similar indicator? Otherwise you will have to check every while with pH paper...Maybe you have a digital meter, that would be good..

    Anyway, it's not hard...Just take x volume (mass it) of plumbo...titrate to pH 7 with known molarity of acid...figure out how many moles of acid were needed to bring to pH 7, and that's how many moles of base are present in x volume of plumbo. Convert these moles to grams, then take this number, divide it by the mass of the volume of plumbo you used = mass %.
  5. May 28, 2004 #4
    We have found out now and I hope we have done well.

    The problem was as follows: Find the mass percentage of NaOh in PLUMBO. Nothing more, nothing less. We needed to plan what tools we were to use, what calculations we were to take and what chemicals we were to use.

    We titrated with HCl three times and evaluated the results and the observations. the calculation method we used was n=m/Mm and then found the mass percentage. It wasn't harder than that though we had been working on it for hours and even our teacher gave us inaccurate or more or less incorrect advices.

    The indicator was BTB!
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