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. 👍
  2. 👎
  3. 👁
  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. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. math

    there are 28 students in a class. 16 of them are boys. What is the percentage of girls in the class?

  2. Business Stats

    In a recent survey in a Statistics class, it was determined that only 60% of the students attend class on Fridays. From past data it was noted that 98% of those who went to class on Fridays pass the course, while only 20% of those

  3. Algebra 2

    1. By graphing the system of constraints, find the values of x and y that maximize the objective function. 2

  4. Statistics

    Of the 40 students in a gym class, 13 played volleyball, 12 ran track (4 of whom did a push up), and the remainder were absent. A.) What proportion of the class ran track? B.) What percentage played volleyball? C.) What percentage

  1. statistics

    In a recent survey in a Statistics class, it was determined that only 60% of the students attend class on Thursday. From past data it was noted that 98% of those who went to class on Thursday pass the course, while only 20% of

  2. math

    The idea of a large, stable middle class (defined as those with annual household incomes in 2010 between $42,000 and $126,000 for a family of three), is central to America's sense of itself. But the U.S. middle class shrank

  3. math

    An objective function and a system of linear inequalities representing constraints are given. Graph the system of inequalities representing the constraints. Find the value of the objective function at each corner of the graphed

  4. Math

    Christie decided to make bracelets for the fifth grade class girls. Two-fifths of the bracelets were finished on Monday, and 3/7 of the bracelets were finished on Tuesday. If she finishes 1/7 of the bracelets on Wednesday, will

  1. maths

    there are 104 students in class 10th and 96 students in class 9th in a school .in a house examination the students ate to be evenly seated in parallel rows such that no two adjacent rows are of the same class. (a) find the maximum

  2. Mathematics

    A class has 32 pupils. If 12 are boys,what percentage of the class are girls?

  3. Programming

    Write the pseudocode to represent the following: Input: Input the name, address, and exam percentage of a students. Process: Calculate the total percentage marks of all the students and the class average. Output: For each student,

  4. Math

    Mr. Williams just finished grading his science exams. The class average score on his exam was 79%. However, he forgot to grade John's paper. John scored an 86% on the exam. What is going to happen to the class average, once he

You can view more similar questions or ask a new question.