In chemistry, the mole is the standard measurement of amount. However, balances DO NOT give readings in moles.
Balances give readings in grams.
So the problem is that, while we compare amounts of one substance to another using moles, we must also use grams, since this is the information we get from balances. There are three steps to converting grams of a substance to moles. Determine how many grams are given in the problem. Calculate the molar mass of the substance. Divide step one by step two.