Chemistry Forums for Students > Undergraduate General Chemistry Forum
Synthesis of silver metal from silver ore
Win,odd Dhamnekar:
How to answer the following problem? I shall try to post the answer given by author in my next post, if required
Borek:
you are here long enough to know it is always required
Win,odd Dhamnekar:
My answer to question a.
[itex]\frac{5.6921 g ore \times 0.216 g Ag}{1.00 g ore}= 1.23 g Ag[/itex]
[itex] \frac{123 g Ag}{107.87 g/gmol}=[/itex] 1.14e-2 mol Ag
[itex]\frac{1.14e-2 mol Ag \times 1 Ag_3PO_4}{ 3 Ag}=[/itex] 3.78e-3 mol
0.00378 mol Ag3PO4 × 418.6 g mol Ag3PO4 =1.59 g Ag3PO4
My answer to question b.
Ksp= 8.89e-17=[Ag+]3 [PO43-]=[Ag+]3[0.12]= [Ag+]= 2.20e-6 M
Silver lost in 2.5 l solution would be
2.20e-6 M × 2.5 l= 5.50e-6 mol Ag
5.50e-6 mol Ag × 107.87 g/gmol Ag = 5.94e-4 g Ag lost [1]
Filteration and washing of Ag3PO4, No common ion, 0.5 l of wash water[ 3(PO43-)]=Ag+
Ksp=8.89e-17 =[Ag+]3[PO43-]=[3[PO43-]]3[PO43-]
[PO43-]=4.26e-5 M, so Ag+= 3(4.26e-5 M)=1.28e-4 M
Silver lost in 0.5 l of solution would be:
1.28e-4 mol/l × 0.5 l= 6.39e-5 mol Ag
6.39e-5 mol Ag × 107.87 g/gmol Ag = 6.89e-3 g Ag lost in washing Ag3PO4 [2]
Total silver lost= [1]+[2]=7.49e-3 g
My answer to question c is 6.58 × 103 g Ag lost.
My answer to question d[itex]\frac{6.58e3 g Ag}{28.35g/ounce}× $5.00/ounce=$1160[/itex] Author's answer is $1700
What are your answers to questions e and f?
Author's answers to question a, b, c are given below:
mjc123:
Once again, we are dealing with different values of Ksp. Are you given a value in the question/textbook, or expected to look it up?
First step of b: how do you get [Ag+] = 2.2e-6 M? I get 9e-6 M.
e and f: as Borek said, you need to show an attempt of your own.
Win,odd Dhamnekar:
Because of one wrong result given by my calculator, I change my answer to silver lost during precipitation. It would be 2.44e-3 M. So total silver lost would be 9.33e-3 g.
My answer to question c is 8.198 × 103 g would be lost.
My answer to question d is $1446.
Navigation
[0] Message Index
[#] Next page
Go to full version