What is the nitrogen pressure in a 0.5m3 vessel at 25C? Gas mass 400g.

Ideal gas equation of state (Mendeleev – Clapeyron):
P * V = (m / M) * R * T, where P is the nitrogen pressure (Pa), V is the volume of nitrogen in the vessel (V = 0.5 m ^ 3), m is the mass of nitrogen (m = 400 g = 0.4 kg), M is the molar mass of nitrogen (M = 0.028 kg / mol, diatomic gas), R is the universal gas constant (R = 8.31 J / (mol * K)), T is the absolute temperature of nitrogen (T = 273 + 25 = 298 K).
Nitrogen pressure in the vessel:
P * V = (m / M) * R * T
P = (m / M) * R * T / V = 0.4 * 8.31 * 298 / (0.028 * 0.5) = 70754 Pa.
Answer: The nitrogen pressure is 70754 Pa.