How to Create 1% Iron Solution - Step by Step Guide

[lesieux]

1% iron solution??

Homework Statement

Dissolve 1.70g of iron III chloride in 99 ml of distilled water. Mix well and label 1% iron.

Homework Equations

I've tried to check the value of the iron percentage but I don't succeed.

The Attempt at a Solution

First I've tried to find out the number of mole of FeCl3,6H2O (M=270g.mol-1) in 1.70 g and found the mass of iron 0.352 g then divide this mass by the total mass (1,7+99), but it doesn't work. Could anyone help me? Thanks in advance.

 

[Borek]

This will be 1% in FeCl₃, not Fe.

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[lesieux]

The protocol is here
http://dwb4.unl.edu/Chem/CHEM869K/CHEM869KMats/SimpleIronLab.html
And i still don't understand "Dissolve 1.70g of iron III chloride in 99 ml of distilled water. Mix well and label 1% iron."
Could anyone show me the calculation to check the 1% iron.
Thanks in advance.

 

[chemisttree]

You are going to determine iron in what form? You are going to report iron as Fe or Fe₂O₃ or FeCl₃? I've got a feeling that you won't be reporting iron as FeCl₃. Find out the form you need and ratio the molecular wt to that of FeCl₃.

I'm guessing that it will be something like 1.7.

 

[lesieux]

Thanks for your help.
Finally I changed the task sheet in this way:
http://vfsilesieux.free.fr/1Seuro/Irondetermination.html

 

[Borek]

I'm guessing that it will be something like 1.7.

That could be accidental, but to prepare 1% w/w FeCl₃ solution you need to dissolve 1.7 g (more precisely 1.68 g) of FeCl₃^.6H₂O in appropriate amount of water.

I wrote concentration calculator just to be able to check such things on the fly...

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[lesieux]

I'm sorry to ask you this question.
It may be obvious but as i didn't succeed.
Would you mind showing me the calculation?
Thanks in advance.

 

[Borek]

Basically you have to calculate what is mass of FeCl₃ in 1.7g FeCl₃^.6H₃O. Start calculating their molar masses. 1 mole of FeCl₃^.6H₃O contains how many moles of FeCl₃?

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[chemisttree]

Assume that the FeCl₃ is anhydrous.

You are asked to label it 0.10 M, not 1%, right? If that is the case, then you are on the right track. Be sure to carefully weigh the FeCl₃ and label it accordingly. You might not need to measure it out to three or four decimals, but you should do so in your calculations.

Remember that moles = grams/formula wt. and that concentration (M) = moles/volume(L)