moles calculation help

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Wildberry
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Joined: Sun Apr 03, 2016 7:28 am

moles calculation help

Post by Wildberry »

Hi all,

I am stuck on this question in preparation for my chemistry test. I have tried it numerous times however each method leads me to the same wrong answer. Urgent help required to get my head around these moles! If some one could show me the working out, it would be much appreciated!!

Question:
You have 200mL of a solution containing 2.4% potassium chloride. How much magnesium chloride should be added to this solution such that when water is added a final volume of 500 mL, the concentration of chloride is 160 mmol/L? (MW MgCL2.6H20 and KCl are 203.3 and 74.5 respectively.

Thank you
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