Well, this probably won't help much, but this is what I found :
The mole is 6.02E23 units
1 mole of ^12C has a mass of 12 g exactly
Therefore, 1 mole of oxygen atom is 16g and one mole of the Oxygen molecule O 2 is 32 g
"M" is the letter for molar mass Units of molar mass are g/mol...