guest wrote:Could you please help me figure out how to convert 12.2 mg/l of Na to mmol/l?
Thanks!
First, a bit of background: The mole is the SI unit for the amount of a substance and one of the seven fundamental SI units. It is defined as the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilograms of carbon-12 (BIPM 1998, p. 97). It is abbreviated "mol," and the number of entities in a mole of substance is given by Avogadro's number, 6.022e+23.
Given that information, a quick trip to a periodic chart
http://www.webelements.com/ tells us that Sodiums atomic weight is 22.989770. This means that one mole of sodium (6.022e+23 molecules) weighs 22.989770 grams
With that, we can figure this out:
We've got 12.2 mg of sodium in one liter. converting milligrams to grams, we divide by 1000, so we've got 0.0122 g/l
Next, we'll divide the number of grams of the sodium by the molecular weight, in moles per gram:
- Code: Select all
0.0122 g/l
------------- = 5.3068e-4 mol/l
22.989770 mol
-------------
g
To convert 5.3068e-4 mol/l to millimoles (mmol) per liter
5.3068e-4 mol/l * 1000 mmol/mol = 5.3068e-1 mmol/l