In a 1L vessel, there is 0.5 mol of gas at t = 0 °, determine the gas pressure in the vessel.

It is known that gases occupy the entire volume provided to them, that is, the volume of gas is V = 1 liter.
Mendeleev-Clapeyron equation for gases:
P * V = n * R * T, where:
P – pressure in Pa,
V – volume in m3, in our case – V = 1 l = 1 * 10 ^ -3 m3;
n is the number of moles, n = 5 moles;
R – universal gas constant, R = 8.31 J / mol * K,
T is the temperature in kelvin, T = 0 + 273 = 273 K.
Find P = n * R * T / V = 5 * 8.31 * 273/1 * 10 ^ -3 = 11343150 Pa = 11.3 MPa
In atmospheres: 1 MPa = 9.87 atm, in our case P = 11.3 * 9.87 = 111.531 atm