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Topic: Molality  (Read 2772 times)

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Offline Violet89

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Molality
« on: May 02, 2013, 12:46:16 PM »
What is the molality of a solution containing FeCl3 (MM = 162.2 g/mol) with a mole fraction of FeCl3 of 0.070?

I know:

m = mol solute / kg solvent
mf = mol solute / mol soln

I have no idea where to start. I'd appreciate help.

Offline Arkcon

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Re: Molality
« Reply #1 on: May 02, 2013, 01:47:40 PM »
To begin this sort of problem, you should start with the definition and the formula for molality.  What is it?  what information to you need to solve it?  And what information do you have, that will fit the formula, and what do you still have to calculate?  They've given you the formulas, so ask your self, what's the same?  What is different?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Borek

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Re: Molality
« Reply #2 on: May 02, 2013, 02:05:17 PM »
Disclaimer: I am not linking to a page where exactly your conversion is discussed/derived, but it shows how to solve similar problem, discussing a little bit of a general approach.

http://www.chembuddy.com/?left=concentration&right=percentage-to-molarity
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline iamback

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Re: Molality
« Reply #3 on: May 08, 2013, 11:01:19 PM »
What is the molality of a solution containing FeCl3 (MM = 162.2 g/mol) with a mole fraction of FeCl3 of 0.070?

I know:

m = mol solute / kg solvent
mf = mol solute / mol soln

I have no idea where to start. I'd appreciate help.

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