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Topic: Percent by mass and molality  (Read 4859 times)

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Offline fchs

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Percent by mass and molality
« on: April 29, 2007, 02:07:18 PM »
I'm having problems solving the following problem:

Propylene glycol, C3H6(OH)2, is sometimes used in automobile antifreeze solutions. If an aqueous solution has a mole fraction = 0.100, calculate

a) the % propylene glycol by mass
b) the molality of the propylene glycol in the solution

The problem I'm having is that there are no weights in grams or anything (I know how to get the grams of the solution, but from there where do I go?). I know how to use % mass and molality equations, I just don't know where to get the info to put into the equations.

Please help

Offline Yggdrasil

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Re: Percent by mass and molality
« Reply #1 on: April 29, 2007, 02:28:22 PM »
Say you have 1 mole of solution.  How many moles of propylene glycol will be in 1 mole of solution?  How many moles of water will be in 1 mole of solution?  What masses of propylene glycol and water will these number of moles correspond to?

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