Hello everyone first time posting here. I have a thermodynamics question that my teacher told me should be realy easy. But I am having a lot of difficulty on it. Any help would be appreciated. For question 2 by simplying plugging in the information given I am able to get the energy of each system before equilibrium without any difficulty. And we know energy is conserved, so this total energy is the same at equilibrium. I'm kind of stuck what to do at this point. My teacher told me to think of the forces at equilibrium. Ok so F net = 0 at equilibrium. My teacher said from there we should be able to say something about pressure. I'm not too sure exactly what that is. I know at equilibrium we can write p(1)v(1)/n(1) = p(2)v(2)/n(2). But doesn't my n(1) and n(2) values change once we reach equilibrium? Also the volume levels of each system, as well as pressure? Oops I guess my attachment is too big. I can't use superscripts on this keyboard so I will use T(1) to denote temperature of system 1. Ok here is the question: Two systems of ideal gases have the following equations of state: 1 / T(1) = 3RN(1) / (2 U(1)), P(1) / T(1) = R N(1) / V(1). 1 / T(2) = 5RN(2) / (2 U(2)), P(2) / T(2) = R N(2) / V(2). Where R = 8.314J / mol K is the universal gas constant. The mole number of the first system is N(1) = 0.5 mol and that of the second system is N(2) = 0.75 mol. The two systems are initially contained in a closed cylinder, separated by a rigid adiabatic wall. The initial temperatures are T(1) = 200 K and T(2) = 300 K, and the total volume is 20 litres. Subsequently, the wall is replaced by a freely movable diathermal piston and the total system is allowed sufficient time to come to equilibrium. a) What is the energy and volume of each system in equilibrium? b) What is the pressure and temperature in equilibrium? Thanks for any help.