Here's how to calculate the moles of sodium hydroxide (NaOH) in 120 grams:

1. Find the Molar Mass of NaOH

* Sodium (Na): 22.99 g/mol

* Oxygen (O): 16.00 g/mol

* Hydrogen (H): 1.01 g/mol

Total molar mass of NaOH = 22.99 + 16.00 + 1.01 = 40.00 g/mol

2. Use the Formula:

* moles = mass / molar mass

3. Calculate:

* moles = 120 g / 40.00 g/mol

* moles = 3 mol

Therefore, there are 3 moles of sodium hydroxide (NaOH) in 120 grams.