CHEMISTRY

My chem class just finished a lab in which the objective was to find the percentage of silver and barium in a nitrate salt mixture by precipitating the chromates, separating out the precipitate from the solvent and spectator ions via filtration, and analysis of the combined precipitate.

In the lab the salt was dissolved and the barium and silver ions were precipitated with excess potassium chromate solution. the precipitate was collected.

i am supposed to find the percentage of silver and barium in the original sample; however i am having a VERY difficult time calculating this.

my teacher suggested either using a system of equations (two unknown variables) or finding the moles and then working from there. but i am really lost.

here is the data:
30mL of K2CrO4 @ .25 M
mass of flask: 95.383g
mass of flask & sample: 96.336g

after the precipate was collected and dried it weighed 0.944 g

any help setting up the calculation is much appreciated. if i didn't explain it well enough i woudl be happy to elaborate. i'm just really struggling right now.

  1. πŸ‘ 0
  2. πŸ‘Ž 0
  3. πŸ‘ 35
asked by Catie
  1. Let X = mass Ag
    Let Y = mass Ba
    ========================
    One equation you can use is:
    X(molar mass Ag2CrO4/2*atomic mass Ag) + Y(molar mass BaCrO4/atomic mass Ba) = 0.944
    Do you have the mass of the sample of nitrates you used? I hope so. Then the second equation would be as follows:
    X(molar mass AgNO3/atomic mass Ag) + Y(molar mass Ba(NO3)2/atomic mass Ba) = mass sample taken.
    When you find X and Y, then
    % follows from that. Let me know if you still have problems.

    1. πŸ‘ 0
    2. πŸ‘Ž 0
    posted by DrBob222

Respond to this Question

First Name

Your Response

Similar Questions

  1. CHEMISTRY-For Dr.Bob

    My chem class just finished a lab in which the objective was to find the percentage of silver and barium in a nitrate salt mixture by precipitating the chromates, separating out the precipitate from the solvent and spectator ions

    asked by Catie on January 29, 2008
  2. Lab in general

    I just read my syllabus for lab and I am kind of shocked at what it says. I do know that I have to write out procedures of the lab in my nbk before coming to lab but I just read that it says "You will NOT be allowed to refer to

    asked by ~christina~ on September 3, 2007
  3. Advice...about chemistry degree Dr.Bob

    Based on the question topic posted by Britney below titled:In your opinion (your answer to this reminded me of something) (I posted the same thing there but I thought it was improper to piggyback on that post so I posted this

    asked by ~christina~ on March 25, 2008
  4. jessie

    hi im doing a post lab sheet for chem class. and im having a little trouble. we did an experiment where we put a mixture into a bath and checked to see how long a color would leave from the mixture. i have temperature 12.6 C ->

    asked by chem on October 15, 2010
  5. Identify the substance

    There was a substance I used in a lab for chem class and I`m not too sure what it was. They were tiny white balls about a millimeter in diameter. What would they be?

    asked by Lena on March 2, 2009
  6. experimental design

    I want to prove a thesis i have, it think my school has an experimental design class, but i cant take it because my schedule is full, but how would i go about proving my thesis? writing a paper? lab report? we never really learned

    asked by Lind on November 11, 2008
  7. Chemistry

    We just had a lab where our objective was to find the molar mass of Copper using electrolysis. A question on my post lab asks: Would it make a difference if Cu(NO3)2, instead of CuSO4, we’re used in the copper half cells in this

    asked by ryancon on October 30, 2018
  8. Final-Chemistry

    I have finals coming up in a week and a half. I know I should have started studying earlier, but I just had an exam in my chem class and was focused on getting the information for that exam mastered before I started studying for

    asked by Katherine on November 30, 2009
  9. Algebra

    My science class is pretty small. There are just 18 students in the class. My teacher, Mr. Burnett, has an unusual system for picking lab partners. He has given each student a number from 1 to 18, and on lab days, he pulls two

    asked by Chioma on December 8, 2016
  10. algebra

    My science class is pretty small. There are just 18 students in the class. My teacher, Mr. Burnett, has an unusual system for picking lab partners. He has given each student a number from 1 to 18, and on lab days, he pulls two

    asked by Linda on November 1, 2011

More Similar Questions