Here's how to calculate the number of moles in 0.100 grams of chlorine:

1. Determine the molar mass of chlorine (Cl):

* The molar mass of chlorine is approximately 35.45 g/mol.

2. Use the formula:

* moles = mass / molar mass

3. Plug in the values:

* moles = 0.100 g / 35.45 g/mol

4. Calculate:

* moles ≈ 0.00282 mol

Therefore, there are approximately 0.00282 moles in 0.100 grams of chlorine.