How do I find conversions for a reaction with phosphoric acid?

[Rub3y]

TL;DR

Salts and oxides react with phosphoric acid. How do I get conversion %?

I have a solid ash mix containing oxides(ZnO, NiO, MgO, Cr2O3, etc.) and salts (Na2SO4, K2SO4, apatite, etc.). I am supposed to write all of the reactions with phosphoric acid (should be between 1 and 2 mol/l) and put it in a simulation for mass and energy balances. But since phosphoric acid is a weak acid, this stuff doesn't 100% convert, right? Or maybe not at all...? I can look for the reactions no problem, but I have no idea how I would search for the conversion %. Can I maybe make some assumptions fe conversion of everything is 50%. Can anyone give me some tips on how I best handle this or which assumptions I can make?

 

[Mayhem]

It's hard to tell. In the end, the conversion (yield) can only be determined experimentally. Stoichiometrically, you simply have to write and balance the equation(s). Phosphoric acid is a weak acid, so you are correct in that it doesn't fully dissociate in water, but this does not mean that the parts that do come from dissociation do not fully react with the other reactants (at least this is a decent assumption).

 

[Rub3y]

It's hard to tell. In the end, the conversion (yield) can only be determined experimentally. Stoichiometrically, you simply have to write and balance the equation(s). Phosphoric acid is a weak acid, so you are correct in that it doesn't fully dissociate in water, but this does not mean that the parts that do come from dissociation do not fully react with the other reactants (at least this is a decent assumption).

Excellent idea! Exactly what I needed.

 

[Mayhem]

Excellent idea! Exactly what I needed.

I hope what I said was clear. Again I would probably run it by @Borek or another experienced chemist. My knowledge of inorganic chemistry is honestly... lacking.

 

[Borek]

I hope what I said was clear. Again I would probably run it by @Borek or another experienced chemist. My knowledge of inorganic chemistry is honestly... lacking.

Nah, what you wrote is perfectly valid, there is no simple answer here and unless someone works with exactly such mixtures and has some hands on experience it is pretty hard to add something.