Here's how to calculate the number of moles in 291.68 grams of hydrochloric acid (HCl):

1. Find the Molar Mass of HCl

* The molar mass of hydrogen (H) is 1.01 g/mol.

* The molar mass of chlorine (Cl) is 35.45 g/mol.

* The molar mass of HCl is 1.01 g/mol + 35.45 g/mol = 36.46 g/mol

2. Use the Formula:

* Moles (mol) = Mass (g) / Molar Mass (g/mol)

3. Calculation:

* Moles = 291.68 g / 36.46 g/mol

* Moles ≈ 8.00 mol

Therefore, there are approximately 8.00 moles in 291.68 grams of hydrochloric acid.