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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: halcyoncxd on December 15, 2012, 11:19:09 PM

Title: Molality to Mole fraction problem
Post by: halcyoncxd on December 15, 2012, 11:19:09 PM
A solution of toluene (also called 1-methylbenzene) in benzene is prepared.  The mole fraction of toluene in the
solution is 0.100. What is the molality of the solution?

I tried working with 1 mol toulene. I got 1 mol toulene/9 mol h20. 1 mol toulene/0.162 kg = 6.2molal.
But the answer is wrong, where did I screw up?
Title: Re: Molality to Mole fraction problem
Post by: curiouscat on December 15, 2012, 11:29:45 PM
Quote from: halcyoncxd on December 15, 2012, 11:19:09 PM
But the answer is wrong, where did I screw up?

In mistaking Benzene for Water.
Title: Re: Molality to Mole fraction problem
Post by: halcyoncxd on December 15, 2012, 11:34:01 PM
Yes but its asking for the molality which is moles solute /kg solvent. The solvent here is h2o i believe.
Title: Re: Molality to Mole fraction problem
Post by: curiouscat on December 15, 2012, 11:35:47 PM
Quote from: halcyoncxd on December 15, 2012, 11:34:01 PM
Yes but its asking for the molality which is moles solute /kg solvent. The solvent here is h2o i believe.

Why not Benzene as solvent?
Title: Re: Molality to Mole fraction problem
Post by: halcyoncxd on December 16, 2012, 12:23:49 AM
O nm, understood thx.