This has been bothering me for some time, as the Dupla Fe test kit
measures Fe in mg/l and the Aquasonic test kit measures Fe in ppm.
According to my periodic table, Fe has an atomic weight of 55.847. So
therefore one Mole of Fe ions would weigh approximately 55.8 grams, allowing
for the fact that the Fe ion has lost electons in becoming an ion.
Avogadro's Number, 6.022E23 using scientific notation, is the number of
molecules that would be present in 1 mole of any substance. As Fe ions are
present as single atoms in solution, 1 mole of Fe ions would weigh 55.8g and
there would be 6.022E23 atoms.
Now water, H2O has an atomic weight of:
H atomic weight 1
O atomic weight 15.9994
H2O then has an atomic weight of 17.9994 or about 18
So one mole of pure H20 has a weight of 18grams. Therefore one litre of water
(which weighs 1kg) contains 55.56 moles or (55.56 * 6.022E23) or 3.35E25
molecules of H2O.
To create a solution then, that contained 1mg/l of Fe ions, we would have to add
(6.022E23 / 55.8) or 1.08E22 ions of Fe to our 1 litre of water.
We would than have 1.08E22 ions of Fe in 3.35E25 molecules of H20. Or to put
it another way,
Interested Quantity Fe ions
------------------------------ *1E6 = --------------------------------------- * 1E6 = 322.4ppm
Total Quantity H2O molecules + Fe ions
322.4 ions of Fe for every 1millon parts of Fe ions and water molecules.
ie: 1mg/l = 322.4 ppm.
If my analysis is correct :-?, these quantities are not similar at all, or have I missed the
bucket completely and covered myself with 10 litres of water or 335E25 molecules of H20
marque crozman ANGFA - NSW
Attachment Converted: c:\eudora\attach\Measurement units mgl and ppm