Hi guys, im having some doubts getting this exercise:20,0 g of

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Discussion Overview

The discussion revolves around a chemistry exercise involving the reaction of iron with sulfuric acid to produce iron (II) sulfate and hydrogen gas. Participants are addressing questions related to limiting reactants, yields, and stoichiometric calculations, with a focus on the purity of the reactants and the implications for the calculations involved.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions how to determine the limiting reactant without knowing the amount of sulfuric acid present.
  • Another participant clarifies that the sample contains 60% iron, implying that the actual mass of iron is less than 20 g.
  • There is a suggestion to follow stoichiometry by calculating the mass of iron, the number of moles, and then the moles of products based on the reaction stoichiometry.
  • Participants discuss the calculation of iron (II) sulfate mass and question whether the approach to calculating the required mass of iron for a specific yield is correct.

Areas of Agreement / Disagreement

Participants express disagreement regarding the interpretation of the problem, particularly about the limiting reactant and the actual amount of iron available for the reaction. There is no consensus on how to proceed with the calculations due to these uncertainties.

Contextual Notes

The discussion highlights the importance of knowing the quantities of all reactants involved in stoichiometric calculations. There is ambiguity regarding the purity of the reactants and how it affects the calculations, which remains unresolved.

Who May Find This Useful

This discussion may be useful for students working on stoichiometry problems in chemistry, particularly those involving limiting reactants and yield calculations.

ignacioserra
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Hi guys, I am having some doubts getting this exercise:

20,0 g of iron (60% purity) are reacted with sulphuric acid (80 % pure) Iron (II) sulphate and hydrogen are formed:

Fe + H2SO4 → H2 + FeSO4

1. Which is the limiting reactant?
2. How much Iron (II) sulphate will be obtained?
3. What volume (r.t.p) of H2 (g) will be obtained?
4. What volume would be obtained if the yield were just 80 %?
5. How much iron should be used in this case if the amount calculated in (2) were to be obtained=

Info
Ar(H)= 1 Ar(O)= 16 Ar (Fe)= 56
Molar volume (r.t.p) 24dm^3

So,
Iron(II) Sulphate mass= 56 + 32 + (16x4) = 152
is that the iron sulphate obtained?

answer to number 5 should the be: 152/0.8?

please, I am needing some help!
 
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How much iron in the sample? How many moles is it?

But there is something wrong - you are not told how much sulfuric acid was present, so question about a limiting reagent doesn't make sense.
 


20 g of iron.
should I do 152/20?
 


ignacioserra said:
20 g of iron.

No, there is no 20 g of iron. There is a 20g sample that contains 60% iron, that's not the same.

should I do 152/20?

Guessing won't get you far.

You have to follow the stoichiometry. That means calculating mass of the iron, calculating number of moles of the iron, calculating number of moles of products (from the reaction stoichiometry), then converting these moles to mass and volume. In this exact order.
 

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