Once you know the mass in amu, you also know how many grams it takes to make a mole. Remember, the mass on the periodic chart tells you two things:

1) The mass in amu

2) The number of grams it takes to make a mole.

When you figure out the mass from the periodic chart, you will find that it is 295.3. That tells you it takes 295.3 grams to make a mole. Thus: 1 mole = 295.3 grams.

You have the number of grams, so you just need to use this relationship to convert from grams to moles, as shown in Example 7.6.