To answer this question, you just need to put all the variable into PV = nRT formula. In this case, the pressure(P) is 2.5 atm, the number of molecule(n) is 1.3 mol, the temperature(T) is 22 celcius= 295.15 kelvin.
Then the volume should be:
PV = nRT
2.5 * V = 1.3 * 0.08206* 295.15
V= 12.59L
