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Topic: calculating the mass of solute in a solution of known molarity  (Read 4902 times)

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Offline kimi85

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How many grams of Na2SO4.10H2O are needed to prepare 355 ml of 0.455 M Na2SO4?

I first calculate the number of moles from the 0.455 M and 355 ml given, then converted it to grams of Na2SO4 then converted it to grams of Na2SO4.10H2O. But my answer is wrong. The correct answer is 50.9 grams.

Is there something wrong? Thanks.

Offline enahs

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Re: calculating the mass of solute in a solution of known molarity
« Reply #1 on: August 14, 2007, 09:23:33 AM »
The answer seems ok.

What do you mean you converted to grams of Na2SO4 and then the the deca hydrate?

Just calculate the molar mass of the deca hydrate, how many grams of that will it take to equal the number of moles in your solution?

« Last Edit: August 14, 2007, 10:37:24 AM by enahs »

Offline kimi85

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Re: calculating the mass of solute in a solution of known molarity
« Reply #2 on: August 14, 2007, 10:09:42 AM »
thank you very much. now i got it.
God bless. :)

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