So, there is a problem given, where diatomic ideal gas N2 is involved. Both blocks have same volume: 1m3. The molar mass of gas is: 28 g/mol. Initial temperature is 300K. I need to find ΔS and PF. First, I did find P1 by using formula: PV = nRT so, P1 = 1*8.3145*300/1 = 2494.35 Pa and P2 = 2*8.3145*300/1 = 4988.7 Pa Finally: I have total moles = 3, and total V = 2 m3. What should I consider next?