How is the mass of carbon related to the mole?

Simply put, you can go from moles to grams and vice versa by using the mass of 1 mole of that substance, i. e its molar mass. For example, the molar mass of carbon is 12.011 g/mol. This means that 1 mole of carbon, or 6.022⋅1023 atoms of carbon, weigh 12.011 g.