1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Concentration problem-with answer

  1. Apr 4, 2009 #1
    1. The problem statement, all variables and given/known data
    hey guys ive got a problem, could ya tell us where i went wrong

    Lithopone is a brilliant white pigment used in water-based interior paints. It is a mixture of barium sulfate and zinc sulfide produced by the reaction
    BaS(aq) + ZnSO4(aq) ZnS(s) + BaSO4(s)
    What mass of lithopone in grams (to 3 significant figures) is produced in the reaction of 227 mL of 0.257 M ZnSO4 and 325 mL of 0.280 M BaS?

    Mole of BaS=0.280*0.325=0.091mole
    mole of ZnSO4=0.0257*0.277=0.0712moles <therefore this is limiting

    i dont know what i should take the molarmass of to work out the mass???

    ANSWER IS 1.93 grams

    anyhelp would be GREATFULLY appreciated.

    2. Relevant equations

    3. The attempt at a solution
    Last edited: Apr 4, 2009
  2. jcsd
  3. Apr 4, 2009 #2


    User Avatar

    Staff: Mentor

    Check your math. Check it twice, as abvious typo is not the error I am thinking about.

    No, 1.93g is not the answer. Probably typo again.

    You are on the right track. Find limiting reagent, find moles of both solids that precipitated, find their masses - and as you are looking for a precipitate mass, add them.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook