An oxygen gas tank has a volume of 8 L and a pressure of 1500 N/m2. If the temperature decreases from 2500 K to 2000 K and its volume increases to 24 L, what is its final pressure?
For a fixed number of moles,
P*V/T = constant, if T is in Kelvin.
Let 1 and 2 denote initial and final conditions
P1*V1/T1 = P2*V2/T2
P2 (the final pressure) = P1*(V1/V2)*(T2/T1)
= 1500 * (8/24)*(2000/2500)
= 1500 *(1/3)*(4/5) = 400 N/m^2