1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Chemistry Problem II

  1. Sep 26, 2007 #1
    My question is:

    Assuming the weight percent of CaCO3 is 50%, calculate the mass of unknown sample required to prepare a 15 mL solution that contains 0.005 M carbonate.

    Well i know that in the sample of unknown, there half of them are CaCO3. I don't know what do to next...........help plz

    Thank you
     
  2. jcsd
  3. Sep 27, 2007 #2
    if you mean the mass percent of CaCO3 is 50% in an unknown sample then, try getting to how many moles of CaCO3 you would need to make a .005 M solution of Carbonate in 15mL
     
  4. Sep 27, 2007 #3
    that means i would need:
    0.015 L x 0.005 mol/L = 7.5 E -5 moles of carbonate which means i neeed 7.5 E-5 moles of CaCO3

    then... ?
     
  5. Sep 28, 2007 #4
    keep going, how do you get mass (grams) from moles? a great equation to know is MM (molar mass) = g/mol

    then you have mass of CaCO3, if its 50% (or 1/2) of the mass (x) your unknown sample ....
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Chemistry Problem II
  1. Chemistry problem (Replies: 9)

  2. Chemistry problem (Replies: 1)

Loading...