weird gchem problem

[polarmolar]

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Which of the compounds listed would form a saturated aqueous solution with the highest electrical conductance?

Kaplan says its choice A, but isn't choice A (and B) insoluble in aqueous solution?

 

[ucla2134]

Which of the compounds listed would form a saturated aqueous solution with the highest electrical conductance?

Kaplan says its choice A, but isn't choice A (and B) insoluble in aqueous solution?

If you look at the information they gave you, the numerical value of Ksp, all of them are insoluble. Thus, to find out the highest electrical conductance is to find out which compound give you the largest the solubility product constant.

 

[polarmolar]

If you look at the information they gave you, the numerical value of Ksp, all of them are insoluble. Thus, to find out the highest electrical conductance is to find out which compound give you the largest the solubility product constant.

I get what your saying but...from what I am looking at in the Kaplan book, they should all be insoluble except CuBr (thats why I picked it lol).

 

[polarmolar]

anyone know?

 

[pbure9]

I get what your saying but...from what I am looking at in the Kaplan book, they should all be insoluble except CuBr (thats why I picked it lol).

CaSO4 has the lowest Ksp which means more products will be fordmed than in the other 3 choices.

And according to that chart, CuBr isn't very soluble

and according to wikipedia:

CuBr is insoluble in most solvents due to its polymeric structure

 

[polarmolar]

CaSO4 has the lowest Ksp which means more products will be fordmed than in the other 3 choices.

And according to that chart, CuBr isn't very soluble

If you look in the Kaplan notes listing solubility rules, only CuBr is considered soluble, the rest insoluble. Considering this, the ksp values don't make sense at all.

 

[Danny289]

Which of the compounds listed would form a saturated aqueous solution with the highest electrical conductance?

Kaplan says its choice A, but isn't choice A (and B) insoluble in aqueous solution?

find X for each
you can eliminate AgI very quickly( X^2= 8.5 X 10^-17===> X~ 9. 10^-9)
X^2 for CaSO4 ======> X^2= 2.4 X 10-5 ====> X~ 5. 10^-3 it is bigger than others.
the answer will be A ( ~ 0.005)

 

[doc toothache]

If you look in the Kaplan notes listing solubility rules, only CuBr is considered soluble, the rest insoluble. Considering this, the ksp values don't make sense at all.

Why would you be concerned with the "solubility rules" when the absolute solubilities are given in the form of Ksp? Since calcium sulfate has the highest solubility of the 4 compounds listed, one would expect it to generate the most ions and thus have the highest electrical conductance.

 

[polarmolar]

Why would you be concerned with the "solubility rules" when the absolute solubilities are given in the form of Ksp? Since calcium sulfate has the highest solubility of the 4 compounds listed, one would expect it to generate the most ions and thus have the highest electrical conductance.

Because the solubility rules in an aqueous solution state that all choices are insoluble except CuBr, so it would be expected that CuBr would have greatest Ksp. The fact that it doesn't causes the confusion, even more so when you have an additional problem like this:

 

[JBarr29]

ok so the best electrical conductor will be the one that ionizes the most in aqueous solution. They will all form 2 ions when they break, so no multiplication is necessary (Something like K2SO4 you would multiply the Ksp by 3 since it makes three ions). The biggest Ksp will dissociate the most. Therefore A is correct. There is a problem similar in destroyer, with a higher level of difficulty because it takes into account more that 2 ions like i said above. if you want me to find the problem number let me know.

 

[doc toothache]

The problem with "rules" is that there are always exceptions.

Because the solubility rules in an aqueous solution state that all choices are insoluble except CuBr, so it would be expected that CuBr would have greatest Ksp. The fact that it doesn't causes the confusion, even more so when you have an additional problem like this: