Consider a gas that follows the equation of state NRT aN² 2 P V - bN V2 This is called van der Waals gas (a,b > 0). For temperatures T > Tc : monotonically decreasing function. Assume T > Tc and Cy = 3NR/2. = 8a p(V) is a 27Rb Consider an insulated box with volume V₁. The box was divided by a wall. One of the compartments had volume Vo at temperature To, which was filled with van der Waals gas of amount N. The other compartment was vacuum. The system was in equilibrium. (i) The wall was removed abruptly. The gas expanded and occupied the entire box. This process is called adiabatic free expansion. The temperature in the box is now T₁ in equilibrium. What is T₁ - To? (ii) The internal energy of the gas does not change by adiabatic free expansion. Why? (iii) Instead of the abrupt removal, the wall was moved through adiabatic and quasi-static process, and the gas expanded to the entire volume of the box. The temperature in the box is now T2 in equilibrium. What is T₂? (iv) Show T₁ > T₂, using the arguments of the second law of thermodynamics.

Consider a gas that follows the equation of state NRT aN² 2 P V - bN V2 This is called van der Waals gas (a,b > 0). For temperatures T > Tc : monotonically decreasing function. Assume T > Tc and Cy = 3NR/2. = 8a p(V) is a 27Rb Consider an insulated box with volume V₁. The box was divided by a wall. One of the compartments had volume Vo at temperature To, which was filled with van der Waals gas of amount N. The other compartment was vacuum. The system was in equilibrium. (i) The wall was removed abruptly. The gas expanded and occupied the entire box. This process is called adiabatic free expansion. The temperature in the box is now T₁ in equilibrium. What is T₁ - To? (ii) The internal energy of the gas does not change by adiabatic free expansion. Why? (iii) Instead of the abrupt removal, the wall was moved through adiabatic and quasi-static process, and the gas expanded to the entire volume of the box. The temperature in the box is now T2 in equilibrium. What is T₂? (iv) Show T₁ > T₂, using the arguments of the second law of thermodynamics.