Using the Ideal gas law: PV = nRT, where P = pressure, V = volume, n = no. of moles, R= universal gas constant, T = temperature.
Given, n = 0.500 moles, T = 301 K, R=0.0821 L•atm/mol•K, V = 2.5 L
Substituting the given values in the Ideal gas equation:
P = nRT/V = (0.500 mol x 0.0821 L•atm/mol•K x 301 K) / 2.5 L = 4.94 atm
The pressure of carbon dioxide gas = 4.94 atm