[Ralja]

In this experiment i am trying to make ferrofluid from 40%Fecl3 , 25%NH3 , 75%oleic acid (as surfactant) , petroleum base carrier fluid made of C10 - C13 hydrocarbons (bacause only that was available in home depo store, originaly used for petroleum lamps) , distilled water and stainless wool for making FeCl2.

Goal is to get hematite then mix it with surfactant and carrier fluid to get ferrofluid.

First problem:

2FeCl3 + Fe = 3FeCl2  problem to make FeCl2 is it has to be mixed with some water for better reaction with wool, but after reaction there is unknown molarity of final solution.
For example we have 10ml Fecl3 , 10ml water and stainless wool to make FeCl2 what woud be molarity
of FeCl2 solution.

Second problem:

2FeCl3 + FeCl2 + 8NH3 + 4H2O = Fe3O4 + 8NH4Cl

Cooking is needed to make hematite but on what temperature and what volumes in ml of 25%NH3 , 40%FeCl3
and FeCl2 produced from first problem is needed to make 100ml of starting solution, later some ammonia gas will evaporate but that does not matter right now when is cooked. 
During cooking surfactant is added like in one of examples 20ml 1.5M FeCl3 and 10ml 1.5M FeCl2 goes 5ml of oleic acid.
how much of oleic acid goes to this 100ml starting solution of 2FeCl3 + FeCl2 + 8NH3 + 4H2O

i am now in chemistry and i tried to calculate M1V1=M2V2 but my calculations only confuses me and they dont make any sense so i am looking for help how to make this calculations for this case.

I have my doubts of using petroleum as carrier fluid it should dissolve oleic acid and rise on surface after some time to separate from water.
Should be stainless wool ok for dissolving iron from it or i can get steel wool but i dont think that does matter because both of the have impurities which have to be filtered out.

Third problem:

Did i choose wright materials to make ferrofluid.

It would be nice if someone answer all questions in order as descriptive that can be. 

[Ralja]

I have mixed 3.58M FeCl3 with steel wool , but only i get is rusty colored solution.
2FeCl3+Fe=3FeCl2
FeCl2 should look like lime green solution.

What is the problem how do i fix it to get FeCl2 ?

[Arkcon]

Hi there, Ralja:, here's one resource on how Fe (II) chloride is made:  https://en.wikipedia.org/wiki/Iron(II)_chloride#Laboratory_preparation

You should try that method first.  Or just buy it.

Your planned method: 

I have mixed 3.58M FeCl3 with steel wool , but only i get is rusty colored solution.
2FeCl3+Fe=3FeCl2
FeCl2 should look like lime green solution.

What is the problem how do i fix it to get FeCl2 ?

Now that method, I know would work to make Cu(I) Cl, I've done it myself in school.  But it may simply not be possible with Fe.  Anyway, you must protect these from the atmosphere, and use promptly.

[Ralja]

I have tried to make FeCl2 by dissolving steel wool in
33% hydrochloric acid olso i did make calculation how much steel wool should be dissolved but only slightly less than half was dissolved.Here is calculation that i made for it : Fe+2HCl = FeCl2+H2
100ml of 10.4M HCl is simply 1.04 mol

1.04 mol HCl x 1mol Fe / 2mol HCl = 0.52 mol Fe or 29.03g 
All of that iron is not dissolved and i dont know why.
Probably something else is reacting with acid but what and in what ratio?

It was dissolving fine steel wool for 2 hours but it didnt dissolve 15g of it and it should 29.03g

[Borek]

While your stoichiometry looks OK, steel is never just Fe, plus, it is a good practice to use excess acid as when the concentration of H⁺ goes down reaction slows down as well.