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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: angel68 on February 10, 2008, 05:25:35 PM

Title: % by mass in solution
Post by: angel68 on February 10, 2008, 05:25:35 PM
density of 1.24g/mL and is 9.14M. Calculate the % by mass in solution. (MW is 63.02g/mL)?

mass solute
------------- x 100 = mass percent
mass solution

(1.24g/mL)(1000mL) = 1.24 x 10^3g --> mass solution

M=mole solute
   ------------
    L solution
I'm having trouble with next step.... Do I use the 9.14M to help get the mass of solute or do I use the MW?

Thanks for your help

Title: Re: % by mass in solution
Post by: Borek on February 10, 2008, 05:46:42 PM
http://www.chembuddy.com/?left=concentration&right=percentage-to-molarity

You will just have to do the reverse.
Title: Re: % by mass in solution
Post by: angel68 on February 10, 2008, 06:38:21 PM
Quote from: Borek on February 10, 2008, 05:46:42 PM
http://www.chembuddy.com/?left=concentration&right=percentage-to-molarity

You will just have to do the reverse.

I'm sorry the reverse of M???  :'(
Title: Re: % by mass in solution
Post by: Borek on February 10, 2008, 06:58:40 PM
No, you have to use the same approach to find out formula for molarity to percentage conversion.

Or - to make things much faster - don't derive everything, just solve final formula for percent concentration.
Title: Re: % by mass in solution
Post by: angel68 on February 10, 2008, 08:06:40 PM
Quote from: Borek on February 10, 2008, 06:58:40 PM
No, you have to use the same approach to find out formula for molarity to percentage conversion.

Or - to make things much faster - don't derive everything, just solve final formula for percent concentration.

Thanks so much!!! I appreciate your help. ;D