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Topic: Dilution problems  (Read 5037 times)

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fbpearce

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Dilution problems
« on: August 26, 2006, 04:57:53 PM »
It has been quite some time since gen chem for me, and I'm having some trouble refreshing myself on how to do dilutions properly. Here's my problem

I have .182g of a substance that has a mw of 364g/mol. I first want to put it into 1L of distilled water. So working w/ moles of my substance I would come up with

.0005 moles/ L

After figuring out the amount of moles for a 10 mL aliquot I need to dilute it w/ 90mL of distilled water. Would I use the m1v1/m2v2 equation?

Thanks!

Ben


Offline sdekivit

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Re: Dilution problems
« Reply #1 on: August 26, 2006, 05:27:10 PM »
I have .182g of a substance that has a mw of 364g/mol. I first want to put it into 1L of distilled water. So working w/ moles of my substance I would come up with

.0005 moles/ L

Ben

There are 3 ways:

(1)The first one you already mentioned: c1*V1 = c2*V2.

(2)Calculate the dilution factor. We dilute here from 10 mL to 100 mL so we dilute 10 x --> concentration decreases 10x.

(3)Calculate the amount of mol in 10 mL solution and divide that by 100 mL to gain the new concentration.

Actually (1) and (3) are the same.

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