[Ayalon]

I'd really appreciate it if someone could help me solve this one:

What would the concentration of Phosphate Ions be in a mixture of 1.5 mol Mg3(PO4)2 in water with volume 2.0L? (Ksp=1.04x10^-24)

Thanks a lot!

[Borek]

Ksp formula?

How is concentration of PO₄^3- related to concentration of Mg²⁺?

Are you expected to neglect hydrolysis, or not?

[Ayalon]

Mg3(PO4)2 3Mg^2+ & 2PO4^3-

Not sure how I'm supposed to get one concentration from the other, also not sure if hydrolysis can be neglected.

[Borek]

Mg3(PO4)2 3Mg^2+ & 2PO4^3-

Not sure how I'm supposed to get one concentration from the other

Stoichiometry. Take a look at the reaction equation.

Write Ksp formula.

also not sure if hydrolysis can be neglected.

Can't decide for you.

[Ayalon]

(3S)^3*(2S)^2= 108S^5 = 1.04x10^-24
S = 6.262x10^-6 M
Don't know how to reach 2PO4 concentration based on Mg3(PO4)2 concentration...

[Borek]

AMount of solid in mixture doesn't matter - that is, if there is enough of the solid to make saturated solution, it won't get "more" saturated if you add more solid.

As I read the question you have a suspension prepared by agitating solid magnesium pohsphate (1.5 moles) with water (2L), If so, your approach looks OK. Just note that so far you have calculated solubility of the salt - that's not the same as concentration of phosphate. Again, take a look at stoichiometry.