[Treetheta]

I have no clue how to start all I did so far was obtain the moles for part a and b I dont know how to use them

The question:

Calculate the empirical formula of hydrated ferrous ammonium sulfate,
Fea(NH4)b(SO4)c(H2O)d, from the following data.
a. 0.7840 g of the salt gives 0.1600 g Fe2O3(s) when heated strongly in air to constant
mass.
b. 0.7840 g of the salt dissolved in water gives 0.9336 g BaSO4(s) when excess
BaCl2(aq) is added.
c. When 0.3920 g of the salt is dissolved in water and boiled with excess NaOH(aq),
NH3(g) is liberated. When this gas is absorbed in 50.0 mL of 0.10 M HCl(aq), the
excess acid remaining after reaction with the NH3(g) requires 30.0 mL of 0.10 M
NaOH for neutralization.

[Borek]

So you know moles of Fe²⁺ and SO₄^2- - what is their ratio?

Try to calculate moles of NH₃ now - do you know what reactions take place in c? Write their equations.

[Treetheta]

it's a 1:4 ratio

but how does that help?

Ian acid-base reaction but how would I go about finding the moles of NH₃

[Borek]

it's a 1:4 ratio

If you say so...

but how does that help?

a:b

Ian acid-base reaction but how would I go about finding the moles of NH₃

Wrte reaction equations. This is stoichiometry.