Here is the way to think through this. Follow closely and put in the numbers where they belong.
BaSO4 ==> Ba^2+ + SO4^2-
Ksp = (Ba^2+)(SO4^2-)
So when you start adding sulfate into the mixture, where will BaSO4 start to ppt? That's when Ksp for BaSO4 is first exceeded and that will be when
(SO4^2-) = Ksp/(0.015) = ?
(NOTE: Since you BaSO4 is less soluble than SrSO4 you don't need the above step--I include it because it helps explain what's going on;)
What happens next. As you continue to add sulfate ion drop by drop, BaSO4 will continue to ppt until what? Until the Ksp for SrSO4 is exceeded then SrSO4 starts coming down with BaSO4. When will that first molecule of SrSO4 appear. When the sulfate ion is
(SO4^2-) = Ksp SrSO4/0.015 = ?
At that exact point, what is the (Ba^2+)? That will be Ksp BaSO4/(SO4^2-) for when SrSO4 starts.
That will tell you (Ba^2+) at that point. The remainder of the BaSO4 has pptd. So what's left in terms of percent?
[(Ba^2+) at this point/0.015)]*100 = % un-precipitated. I did a quicky estimate and it's about 0.05% but you should confirm that and 0.05% is NOT the answer; just close if I didn't make a mistake. I only went through it once.
I'm not sure how to set this question up...
A solution containing 0.015M Sr^2+ and Ba^2+ ions is treated with Na2SO4 and a percipitate containing one metal sulfate forms. Assition of the sulfate ion continues until the more soluble sulfate salt just begins to percipitate. What % of the less soluble metal ion remains in solution?
ksp(SrSO4)= 2.5x10^-7 and ksp(BaSO4)=1.1x10^-10
BaSO4 ---> Ba2+ + SO42¯
Since BaSO4 is more soluble it will percipitate last?
4 answers
I answered the S + NO problem back on page 3 or 4.
I really suck at Chemistry = [
Thank you for taking the time to explain it to me and answer my many questions! It is very helpful!
Thank you for taking the time to explain it to me and answer my many questions! It is very helpful!
I'm surprise AND I disagree with you. Your posts show more work and better thinking than many of the students that post and in most cases you've worked through most of the problem but just stuck on one point near the end and need to jump that one hump. So don't get discouraged. I think you have been doing great.