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Author: Subject: Dilutions in Chemistry

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sad.gif posted on 1-10-2009 at 16:59
Dilutions in Chemistry

What volume of .0250 M MgCl2 should be diluted to 250.0mL to obtain a solution with the [Cl] ion = .0135 M
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[*] posted on 1-10-2009 at 17:20

Firstly I would post this in the Beginnings section.

Here goes:

So you have a .0250M MgCl2 solution. So you have 0.0250 moles of Mg and Cl2 (in a 1L soln).
This means that you have 0.05 moles of Cl- (again in a 1L soln).

So your solution is a 0.05M solution of the Cl- ion.

The moles in the original solution and the moles in the diluted solution will be equal.
n = n
But n = cv
So cv = cv
0.05*v = 0.0135 * .250
v = 0.0675L
v = 67.5mL

I hope that's right!

Pray tell you actually learn the method from this instead of me just doing your homework!


[Edited on 2-10-2009 by Formula409]
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[*] posted on 1-10-2009 at 17:30

molarity x volume = molarity x volume

2(0.0250)V = (0.0135)(250.0)

The single most important condition for a successful synthesis is good mixing - Nicodem
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