1. Find the molar mass of H₂O:

* Hydrogen (H) has a molar mass of 1.01 g/mol.

* Oxygen (O) has a molar mass of 16.00 g/mol.

* Since there are two hydrogen atoms and one oxygen atom in water:

* Molar mass of H₂O = (2 * 1.01 g/mol) + (1 * 16.00 g/mol) = 18.02 g/mol

2. Use the molar mass to convert moles to grams:

* grams = moles * molar mass

* grams = 2.50 moles * 18.02 g/mol

* grams = 45.05 g

Therefore, there are 45.05 grams in 2.50 moles of H₂O.