# Mol fraction to percentage

1. Mar 2, 2016

### rwooduk

Hi, please could someone give me some advice on how I would convert the mol fraction to percentage? i.e. I want a gas mixture of Argon and Carbon dioxide with only 0.02 mol fraction of CO2, what would this be as a percent?

I tried using this:

http://www.convert-me.com/en/convert/percent/mole.html [Broken]

And when I put 0.02 in I get 1.204*10^24 in the percent term, how can this be a percentage?

Thanks for any help with this.

Last edited by a moderator: May 7, 2017
2. Mar 2, 2016

### BvU

No idea what that site is doing.

But you can use the ideal gas law to discover that mol % = volume %.
If you want weight % you have to bring in the molecular weights:$$wt\%_i = {MW_i * mol\%_i\over \Sigma_j MW_j * mol\%_j }$$

3. Mar 2, 2016

### rwooduk

That's extremely helpful thankyou! Ahhh yes I see now, but just airing on the side of caution please could you confrim that 0.02 mol frac would be equal to 0.02%