chem
posted by ngugi .
how can i figure out how to calculate molecules to grams ?

If I understand your question, it would probably be how to calculate the mass of a molecule.
ex.
N2
mass N2  2(14.001) = 28.002 g/mol
Thus 1 molecule of N2 = 28.002 g/mol 
You remember that 1 mol of a material contains 6.022 x 10^23 molecules. So convert what you have in grams to moles, and multiply by 6.022 x 10^23.