Chemistry: Prediction of producs

[markelmarcel]

Homework Statement

Predict products (and then write formula unit, total ionic unit & net ionic equations)1. Sodium Nitrate, Ammonium sulfate and Iron (III) acetate.

2. Na₃PO₄ + RbClO₃ + Sr(NO3)₂

Homework Equations

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The Attempt at a Solution

1. NaNO₃ + (NH₄)₂S + Fe(CH₃CO₂)₃
I just don't know how to decide what parts will be "spectator ions" and how the 3 products will work out... I know it deals with acids and bases, but my prof went through it really fast and I tried reading our textbook but it didn't help very much with the 3 reactants, and he went out of town for a conference so I couldn't ask him for help...

I think that Fe and S will come together to make a precipitate which would be Fe₂S₃ and then I'm assuming that the NH₄CH₃CO₂ would then combine together, leaving the NaNO₃ as the spectator ions?

 

[Borek]

Sulfate or sulfide? Sulfide precipitation is a good idea. Similar approach will work for the second question - just think, what combination of ions will produce something insoluble. And don't overdo - ammonium acetate will be just a spectator.

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methods

 

[markelmarcel]

Sulfate or sulfide? Sulfide precipitation is a good idea.

ah, touche! it is sulfate- don't know why when i typed it out i made it into sulfide. i was doing my own chemistry ;)

 

[markelmarcel]

Ok so for the first one I got...

NaNO₃ + 3(NH₄)2SO₄ + 2Fe(CH₃CO₂)₃ $$\rightarrow$$ Fe₂(SO₄)<sub>3 [/SUB](s) + 6NH4CH3CO2

When I looked up what I had for my solubility rules I found
Na3PO4, RbClO3 and Sr(NO3)2 to all be soluble... So where do I go from here? Randomly place things together??</sub>

 

[Borek]

Iron (III) sulfide is insoluble, but sulfate is soluble. No reaction if you ask me.

In the second question one of the combinations of cation and anion give insoluble salt.

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methods

 

[markelmarcel]

Ok I'm still working on balancing but for the second I'm assuming the insoluble salt has to be Sr₃(PO₄)₂

Because PO₄ is insoluble, as is Sr (with it being a group II cation).

 

[Borek]

Ok I'm still working on balancing but for the second I'm assuming the insoluble salt has to be Sr₃(PO₄)₂

Like calcium and barium phosphates and sulfates.

Because PO₄ is insoluble, as is Sr (with it being a group II cation).

No such thing as insoluble PO₄ - it is PO₄^3- and it never exists without counterion.

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