Consider a well-insulated horizontal rigid cylinder that is divided into two com
ID: 1855574 • Letter: C
Question
Consider a well-insulated horizontal rigid cylinder that is divided into two compartments by a piston that is free to move but does not allow either gas to leak into the other side. Initially, one side of the piston contains 1 m3 of nitrogen gas at 500 kPa and 120?C while the other side contains 1 m3 of helium gas at 500 kPa and 40?C. Now thermal equilibrium is established as a result of heat transfer through the piston. Using constant specific heats as in problem 1, determine the final equilibrium temperature in the cylinder. What are the respective volumes of the gases at equilibrium? What would the temperature be if the piston were not free to move? In this case, what would the respective pressures be?Explanation / Answer
PV = mRT Q = m(T2-T1)Cp 3. The attempt at a solution I used the specific heat at constant pressure to solve the first part of the problem (Cp) Cp N2 = 1.039 Cp He = 5.1926 Using the ideal gas law i found the mass (kg) of each gas m = (PV) / (RT) m N2 = 4.77 kg m He = 0.807 kg then using the energy from one side of the cylinder equal to the other to find the final temperature of the system Q N2 = Q He (4.77)(T2-80)(1.039) = (0.808)(T2-25)(5.1926) I get T2 = 384K or 111 C