Percent to Molarity in Chemistry?

A

Alice

New member
The density of an aqueous solution of HCl that is 20.00 percent by weight is 1.0980. Calculate the molarity (M) of this solution.

How do I solve this? What's the answer?
 
Use the density first.
20.00% by mass of the density is the mass of the HCl.
The formula for molarity is M = moles/ liters of solution
so

M = 1.0980 g solution x 0.20000 HCl x 1000 ml x 1 mole HCl
--------------------------------------------------------------
1 ml x 1 x 1L x 36.5 g HCl


the numbers crunch as follows

1.0980 x .2000 x 1000 x 1 divided by 1x1x1x36.5

this equals 6.016 moles/liters or 6.016 M.

these kinds of problems are easily answered by using labels and making sure that the labels cancel out so that you get the appropriate units of measure. Hope this helps
 
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