How do i convert grams to moles?

This requires you to understand the mole concept. If you have a given number of grams of a substance then you can find the number of moles of that substance by knowing the molar mass or formula mass of that substance.

For instance, if you have 22.0 grams of CO2, how many moles do you have? From the periodic table you find that the mass of C is 12.0107 amu, the mass of O is 15.9994 amu. For a mole of C you just change the units from amu to g. The same is true for O. So the molar mass of CO2 is 12.0107 g + 2 x 15.9994 g = 44.0095 g/mole

moles CO2 = 22.0 g CO2 ( 1 mole CO2/44.0095 g CO2)

moles CO2 = 0.500 moles

grams X (mole/g)

use the molar mass that has units of grams/mole. Invert it.

grams X (mole/g)

You have to know the molar mass

molar mass = grams/ mol that is your conversion factor.