I'm in the same class as Catie, and we're working on the same lab; however, i chose a different approach.

here's what i have below, your help is much appreciated.

so i have X= g AgNO3
0.953-x = Ba(NO3)2
therefore .953-X-NO3=?

so far I caluclated the % of Ag and Ba in their nitrate salts:

% Ag in Ag2NO3= 107.87/161.91
= .666X

% Ba in Ba(NO3)2 = 137.33/261.32
= .526(.953-X)

i got this far, but now i'm stuck.

  1. 👍 0
  2. 👎 0
  3. 👁 36
asked by Jake
  1. sorry, it would probably hep you to know that the objective is to calculate the percentage of silver and barium in the nitrate salt mixture. i know how to find the percentage once i get the grams, but i have no idea how to get the grams from this point.

    thanks :]

    1. 👍 0
    2. 👎 0
    posted by Jake
  2. A couple of starting points for you but not finished.
    First, you are ok with X = AgNO3 (note you wrote Ag2NO3 a few lines below that but apparently you didn't use that formula throughout.
    Second, you have avoided the need for a second variable by using 0.953-X and that's ok, too, but you still need a second equation.
    Third, 0.953 - X - NO3 I don't get. If you want to get rid of the nitrate ion, which apparently is what you are driving at, it's easier to let X = Ag and make the conversions as I did for Catie.
    Fourth, your factor AgNO3 (written with a typo of Ag2NO3) is not correct. Ag is ok at 107.87 but AgNO3 is closer to 170 although I don't remember the exact number. I THINK it is 169.87 so your factor of 0.666 is not correct.
    Fifth, you need a second equation utilizing the BaCrO4.
    I'll leave it at that to let your work through some of this but I'll be glad to help later.

    1. 👍 0
    2. 👎 0
    posted by DrBob222
  3. Yes, I didn't want to use a second variable because my teacher wants us to use different approaches.

    i checked the molar mass of AgNo3 and it is 169.87, so thank you. I didn't notice that.
    the new factor would be:
    107.87/169.87 = .635

    i'm not quite sure how to remove the nitrate, that was just a note i threw down and wasn't sure how to go about it.

    i'm still really confused as to how the calculation works for this :/
    i thank you so much, i promise i'm not looking for you to do answer the ? for me,i'm just really really confused, i've been tearing my hair out over this calculation!!!

    i wrote the balanced equations out.
    i thought it might help me figure it out.
    i know there's 2*more AgCro4 in the product.

    2Ag + CrO4 (-2) ---> Ag2CrO4
    Ba (2+) + CrO4 (-2) ---> BrCrO4

    but how would that help me make up a second equation? would it be the % of Ba in BaCrO4? Would this work if i followed a similar method?

    % Ba in BaCrO4 = 137.33/261.33
    = .526

    1. 👍 0
    2. 👎 0
    posted by Jake
  4. Two or three points here.
    If you let X = mass AgNO3
    then 0.953 - X = mass Ba(NO3)2.
    First, if we set this up with just this information, the following is what you get.
    X + 0.953 - X = 0.953
    and we end up with 0 = 0, which of course, is true but it doesn't help us much if the idea was to solve for X. :-)).That's why you need a second equation. That's where the mass BaCrO4 comes in. You must understand that the whole idea behind doing the BaCrO4 thing is to ppt ALL of the Ag and ALL of the Ba as BaCrO4.
    Second, back to the X and 0.953 - X thing, if you multiply X by the percent Ag in AgNO3 and 0.953 - X by the percent Ba in Ba(NO3)2, you will have converted AgNO3 to Ag and Ba(NO3)2 to Ba and that, eventually, is what you want in order to calculate percent Ag. If you will look at the equations I made for Catie, you will see those factors are what I did, also, except I started with Ag and Ba so I converted to AgNO3 and Ba(NO3)2. You are using a different set up so that won't help you. So on to the BaCrO4.
    You want to convert g AgNO3 (that's what X is) to Ag2CrO4 and you want to convert 0.953-X [that's the Ba(NO3)2] to BaCrO4, add those together and the sum should be 0.944 grams BaCrO4.
    No matter how you slice it though, if my algebra stuck together last night, I tried solving the equations and I came up with a negative number for one of the salts and a positive number for the other one. A negative number can't be; therefore, I concluded that either I made an error OR there was an error in the procedure. I think my algebra is ok. I think the mass BaCrO4 or the mass of the sample (or both) are in error due to experimental error.

    1. 👍 0
    2. 👎 0
    posted by DrBob222
  5. so the second equation would be:

    0.635X + 0.526(0.953-X)=0.944 ?????

    0.635X + 0.5013-.526X=0.944

    to three sig figs=4.06 is that the grams of BaCrO4???

    1. 👍 0
    2. 👎 0
    posted by Jake
  6. that couldn't be right though because i only started out with .953 g and conservation of mass applies

    1. 👍 0
    2. 👎 0
    posted by Jake

Respond to this Question

First Name

Your Response

Similar Questions

  1. 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
  2. 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
  3. Organic Chemistry

    In lab, we purified acetanilide through recrystallization. We did not have have time to test the melting point to check the purification, so we put the recovered crystals in a 50ml beaker, covered the top with parafilm with a few

    asked by Rayna on October 27, 2014
  4. math

    the biology class has a lab every days. the earth science class has a lab every three days . which class day do they both have class ?

    asked by mike on October 22, 2013
  5. algebra

    how do I help my son answer this question/ cary spent 1/3 of his class working on fraction problems and 3/6 of his class working on algebra problems. He spent the last 10 minutes of his class reading a chapter in his textbook. How

    asked by abby on February 1, 2007
  6. Socials

    Transportation Upper class -carriage material -Chariots -Litters Transportation Middle Class -paddle by bike -walk by foot -Wagons -Horses? -Carts Transportation Working Class -walk by foot Is that all I need for working class?

    asked by Sara on December 1, 2009
  7. social studies 9

    using the data in table5-1, determine how large a part of the popualtion was considered working class what proportion of liverpool's popualtion had sub-standard housing? compare the death 1845 Census Tole population 223 054 people

    asked by amy on January 1, 2012
  8. Honors Chemistry

    We did a lab in class on Friday where we stuck a metal loop in various chemicals and stuck it in the flame of a Bunsen burner and we observed the flame's colors as the different metals went in. For every lab we do, we have to

    asked by Emily on September 20, 2009
  9. History

    Thanks, for for your suggestion.Please check on the following questions, if I have the correct answers. Question 1 During World War I the most striking break from pre-war conditions on the home front was Answer (A)the use of

    asked by Adesuwa on August 26, 2010
  10. Algebra

    A student receives his grade report from a local community college, but the GPA is smudged. He took the following classes: a 2 hour credit art, a 3 hour credit history, a 4 hour credit science course, a 3 hour credit mathematics

    asked by Anonymous on August 13, 2018

More Similar Questions