Consider four sealed, rigid containers with the following volumes: 50 ml, 100 ml, 250 ml, and 500 ml. if each of these contains .25 moles of helium gas at standard temperature, which container would have the greatest pressure?

First, we assume that helium behaves as an ideal gas such that the ideal gas law is applicable.
                                     PV = nRT
where P is pressure, V is volume, n is number of moles, R is universal gas constant, and T is temperature. From the equation, if n, R, and T are constant, there is an inverse relationship between P and V. From the given choices, the container with the greatest pressure would be the 50 mL. 

En CNPT un mol de cualquier gas ocupa 22,4 litros

Entonces hay que multiplicar

2.5 x 22.4 litros y eso es igual a 56 litros de gas metano

PD: CO2 es dióxido de carbono, metano es CH4