Molarity problem

[LoLPoPs]

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The problem says:

150 mL of a 3 M KCl solution is diluted with 500 mL of distilled water. The resulting solution is stirred and 300 mL are poured out of the beaker. What is the molarity (in moles/liter) of the remaining solution?

I'm confused how to go about this problem...
Can someone explain please? 😍

Thanks in advance!!!

 

[UndergradGuy7]

The problem says:

150 mL of a 3 M KCl solution is diluted with 500 mL of distilled water. The resulting solution is stirred and 300 mL are poured out of the beaker. What is the molarity (in moles/liter) of the remaining solution?

I'm confused how to go about this problem...
Can someone explain please? 😍

Thanks in advance!!!

m1v1=m2v2
(150)(3M)=(650)(x M)
solve for X

or 150 mL * 3M = moles of KCl
then new concentration is moles of KCl/total volume or moles KCl/650 mL

300mL of the solution (KCl and solvent) is poured out... this does not change the concentration though...
Example.. I tell you to get 20 mL of 1 M HCl from a flask. You get it. Does the concentration of the HCl remaining change? No its still 1M, just less mL's of it.

 

[LoLPoPs]

ohhhhhhhhh i get it now!!! Sounds like a completely different problem when you explain it!
Thanks for the wonderful explanation !!!!! It's so easy to follow 😍