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Homework Help: Precipitate lab help

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  1. Sep 26, 2017 #1

    sn1

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    1. The problem statement, all variables and given/known data
    I have a percipitate lab.
    We have an unknown sulfate powder that we mixed with water and then added Barium Nitrate in order to get the sulfate out of the mix. The entire sulfate, nitrate mixture was mixed with HCl to make the particles bigger and then it was heated for flocculation. I filtered out the percipitate and got it's mass, as well as the volume of the new nitrate solution. Right now the equation is looking like:




    2. Relevant equations
    XSO4 +Ba(NO3)2 --> XNO3 +BaSO4

    3. The attempt at a solution
    I was thinking of using mass percents
     
  2. jcsd
  3. Sep 26, 2017 #2

    Borek

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    Staff: Mentor

    Wouldn't hurt if you told us what for you want to use these mass percentages.

    In other words: you have described the procedure, but you have not explained what was the aim of the experiment.
     
  4. Sep 26, 2017 #3

    sn1

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    Sorry!! I need to find what the unknown substance is.
     
  5. Sep 26, 2017 #4

    hilbert2

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    Gold Member

    Do you know the mass of the original sulfate powder? With that information and the mass of the precipitate, you can calculate the molar mass of element X by simple stoichiometry.
     
  6. Sep 26, 2017 #5

    sn1

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    Yes I have the mass of the original sulfate powder. I tried my best to get it as close to 1gram as possible, and there is about 24.88mL of the barium nitrate (because its concentration level we calculated how much we needed in order to make the best possible reaction). We then added 1 mL of HCl, and heated it in order to make the precipitate particles as large as possible.

    Your idea is what I thought should be done, but got a bit confused because so much is happening within the lab. Thank you!!
     
  7. Sep 26, 2017 #6

    hilbert2

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    Also note that there may be more than one metal ion for every sulfate ion in the original sample, as in ##Na_2 SO_4##.
     
  8. Sep 27, 2017 #7
    Have you established which metal your unknown sample contains?
     
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