Colligative Property Question

[Troyvdg]

---

Members don't see this ad.

When predicting bp elevation/vapor pressure depression/freezing point depression based on given molarity, why does the solubility of the molecule matter?

i.e.

which would cause the greatest bp elevation when adding 5 mols in 10L?

BaSO4
or
CH3OH
answer is BaSO4 because it dissociates into Ba and SO4, but the fact that BaSO4 is insoluble confuses me.

If you compared BaSO4 with KCl would KCl have the largest elevation since it is more soluble and will have more particles in solution (since they both have a van hoff factor of 2)?

 

[412smb412]

When predicting bp elevation/vapor pressure depression/freezing point depression based on given molarity, why does the solubility of the molecule matter?

i.e.

which would cause the greatest bp elevation when adding 5 mols in 10L?

BaSO4
or
CH3OH
answer is BaSO4 because it dissociates into Ba and SO4, but the fact that BaSO4 is insoluble confuses me.

If you compared BaSO4 with KCl would KCl have the largest elevation since it is more soluble and will have more particles in solution (since they both have a van hoff factor of 2)?

t = kim

i = parts it ionizes into
m = molality

play with the variables, it depends also on molality and k

 

[Troyvdg]

t = kim

i = parts it ionizes into
m = molality

play with the variables, it depends also on molality and k

You misunderstood the question. But thanks anyway

 

[Menthol]

When predicting bp elevation/vapor pressure depression/freezing point depression based on given molarity, why does the solubility of the molecule matter?

i.e.

which would cause the greatest bp elevation when adding 5 mols in 10L?

BaSO4
or
CH3OH
answer is BaSO4 because it dissociates into Ba and SO4, but the fact that BaSO4 is insoluble confuses me.

If you compared BaSO4 with KCl would KCl have the largest elevation since it is more soluble and will have more particles in solution (since they both have a van hoff factor of 2)?

solubility is a non-colligative property thus I dont think it would affect bp elevation+mp depression

 

[Ferneezy]

is the OPs question an actual, verifiable question from review material or a practice test (in the vein of "Answer E: trick question because ionic cmpd is insoluble)?

or is he just riffing this like a frankenstein amalgam of various gen chem topics and as such will never be something we see on the real DAT?

 

[Troyvdg]

it was an actual question. but DAT done! thanks for the responses