Chemical Forums

Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Ryumexicano on September 25, 2014, 12:46:24 AM

Title: Unit conversion
Post by: Ryumexicano on September 25, 2014, 12:46:24 AM

Hey guys.  I was just wondering if someone can guide me in the right direction to convert concentration from mg/L to M.

The lab asks to convert our values of molarity in mg/L (which I have) and I am not sure how to convert them to M (moles/L).  I don't want to mess my lab notebook with wrong calculations.  I have an idea.

I am calculating molarities of MO (Methyl Orange), which we used in a Kinetics experiment.  I have all my concentrations in mg/L but I want M, not required, but just in case we get asked. 

Can I use the density of MO and molar mass to find the concentration in M? Please, I am a bit confused on how to do this. I know it's a simple conversion, but any help is appreciate it.


Thanks!

Title: Re: Unit conversion
Post by: curiouscat on September 25, 2014, 02:18:58 AM

Whats the MW. With units.

Just convert mg to gm. Then gm to gmol.

1 M = 1 gmol / L

At mg conc. the densities wont matter much. I'm assuming it's dissolved in water?

Title: Re: Unit conversion
Post by: Irlanur on September 25, 2014, 04:46:17 AM

why should the density matter?