I. A cylinder with a valve at the bottom contains an ideal gas. The valve is opened and some of the gas escapes slowly. The valve is then closed. after which the equilibrium with the surroundings at all times and that the piston is free to move without friction. piston is observed to be at a lower position. Assume that the system is in thermal 835 a. In the spaces provided.draw two free-body diagrams for the piston: one for an instant before the valve is open and one for an instant afterward. Free-body diagram for piston ' before the valve is opened Free-body diagram for piston l after the valve is opened b. Is the nal pressure of the gas in the cylinder greater than. less than. or equal to the initial pressure? Explain. c. In this process, which of the quantities P. V. n. and T are held constant and which are allowed to change? d. Consider the following incorrect student statement. \"In the ideal gas low, P = nRT/V, so the pressure is inversely proportional to the volume. If you decrease the volume. the pressure has to go up.\" What is the aw in the student's reasoning? e. Explain why it is not possible to use the ideal gas law to determine whether the pressure changed in this process