How to Make Mohr's Salt: Water and Solution Amounts Needed?

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Discussion Overview

The discussion revolves around the synthesis of Mohr's Salt (Ammonium Iron (II) Sulphate), specifically focusing on the amounts of water and the required solutions (Iron Sulfate and Ammonium Sulphate) needed for the reaction. The scope includes chemical reactions, stoichiometry, and practical considerations in the preparation process.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant inquires about the specific amounts of water and solutions needed for making Mohr's Salt, assuming equimolar conditions.
  • Another participant suggests starting with the synthesis reaction equation to determine the necessary amounts.
  • Participants discuss the reactions involved, including the hydration of FeSO4 and the need for water in the reaction process.
  • One participant proposes two methods for calculating the amounts of reactants: using stoichiometry based on the total synthesis reaction or determining the moles of each reactant needed per mole of Mohr's Salt.
  • There is a clarification about the stoichiometry of the reactants, noting the moles of iron, ammonia, and sulfuric acid required for the synthesis.
  • Some participants express uncertainty about the starting materials, questioning whether the synthesis begins with sulfates or with iron and ammonia.
  • A participant mentions preparing the double salt from scratch and questions whether this poses any problems.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the exact amounts of reactants needed or the starting materials for the synthesis. Multiple viewpoints and methods for calculation are presented without resolution.

Contextual Notes

Participants do not fully resolve the assumptions regarding the hydration of FeSO4 or the specific stoichiometric ratios required for the synthesis.

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When making Mohr's Salt (Ammonium Iron (II) Sulphate) how much water am I required to add OR how much of each solution must I use.

Thanks

Assuming it is equimolar, how much of each (Iron Sulfate and Ammonium Sulphate) Do i need
 
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Start with synthesis reaction equation.
 
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Borek said:
Start with synthesis reaction equation.

--

The reactions are:

Fe + H2SO4 --> FeSO4 + H2

NH3 + HSO4 --> (NH4)2SO4

But i know that the FeSO4 should be hydrated (FeSO4-7H2O) - how is this achieved
 
Reaction takes place in water, so there is no problem with water source, don't you think?

Main problem is how to calculate amount of iron, ammonia and sulfuric acid. But it is not that difficult. Two possible ways - one, write total reaction of synthesis (that is, but ammonia, iron and sulfuric acid on the left, Mohr's salt on the right) and do simple stoichiometry. Second - how many moles of iron per 1 mole of Mohr's salt? How many moles of ammonia? Of sulfuric acid? Can you use this information to calculate how much of each reactant you will need to produce 1 mole of Mohr's salt?
 
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Borek said:
Reaction takes place in water, so there is no problem with water source, don't you think?

Main problem is how to calculate amount of iron, ammonia and sulfuric acid. But it is not that difficult. Two possible ways - one, write total reaction of synthesis (that is, but ammonia, iron and sulfuric acid on the left, Mohr's salt on the right) and do simple stoichiometry. Second - how many moles of iron per 1 mole of Mohr's salt? How many moles of ammonia? Of sulfuric acid? Can you use this information to calculate how much of each reactant you will need to produce 1 mole of Mohr's salt?

Fe + H2SO4 --> FeSO4-6H2O + H2

NH3 + H2SO4 --> (NH4)2SO4

We have 1 mole of Iron in the Iron (II) salt and 1 mole of sulphate
In the Ammonium salt, we have 2 moles of ammonium and one mole of sulphate.

Does that mean we need 1 mole of FeSO4 and 1 mole of (NH4)2SO4
 
Yes. But from your equations I got the impression that you start not with sulfates, but with iron and ammonia.
 
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