## Chemistry: The Central Science (13th Edition)

Molar mass has units of grams/mole. If we have that 0.00105 moles has a mass of 0.406 grams, we just set up a ratio as follows: $\frac{0.406g}{0.00105 mole}= \frac{x grams}{1 mole}$ Then we cross multiply and find that: 0.406 = 0.00105x and therefore x = 386.667, which translates to 386.667 g/mol