Final answer:
The quantity of hydrogen gas in moles that would occupy the vessel is 2.55 mol.
Step-by-step explanation:
To calculate the quantity of hydrogen gas in moles, we can use the ideal gas law equation, PV = nRT. Rearranging the equation, we have n = PV / RT. Plugging in the values given: P = 23.3 atm, V = 8.50 L, T = 150.0 °C = 423.15 K, and R = 0.0821 L·atm/(mol·K), we can solve for n.
n = (23.3 atm) × (8.50 L) / (0.0821 L·atm/(mol·K) × 423.15 K) = 2.55 mol.
Therefore, the quantity of hydrogen gas in moles that would occupy the vessel is 2.55 mol.