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Homework Help: 40.0g NaCl that is 90% by Mass, find Mass

  1. Jan 12, 2010 #1
    1. You will prepare 40.0g of a NaCl solution that is 0.90% by mass. Calculate the mass of the NaCl that is needed.


    2. I don't know the proper equations/steps to find the answer, this is really what I need help with.


    3. I have not made an attempt yet as I don't know how to go about making an attempt. Hopefully somebody could point me in the right direction so I can figure this out.

    Also I did do a search though I was unable to find anything that seemed to deal with my situation.

    -Britt
     
  2. jcsd
  3. Jan 12, 2010 #2
    Try looking at it this way first: If you needed to prepare a 100. g solution of NaCl that is 10.0% by mass, what mass of NaCl is needed?
     
  4. Jan 12, 2010 #3

    Borek

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    Staff: Mentor

    Other hint: you can solve the question using just definition of mass percentage and basic algebra to rearrange the formula.
     
    Last edited by a moderator: Aug 13, 2013
  5. Jan 13, 2010 #4
    Thanks for the help it seemed I was over thinking the question a bit. I came up with 0.36g NaCl
     
  6. Jan 13, 2010 #5

    Borek

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    Staff: Mentor

    Can't say I am surpsised :smile:
     
    Last edited by a moderator: Aug 13, 2013
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