The formula for converting moles, molar mass, and moles between each other is:

n = m/m

n is the number of moles

n = m/m

n is the number of moles

m is the mass (in grams)

M is the molar mass of the chemical formula.

For example, when converting 500 grams to moles for HCl (hydrochloric acid) you would do the following:

n= ?

m= 500g

M = 36.461g/mol

500/36.461 = 13.71328

The last step is to make sure the significant digits are concordant with the data given. Usually on your Periodic Table of Elements, the molar mass will be 4 significant digits. In this case, I used 3 sig digs for the amount of grams. Thus, your answer, rounded to the lowest number of significant digits would be:

13.7mol