Chapter 6, Problem 6.10CU

i) Use the thermodynamic identity for a P-V-T system and the equation of state to show that the entropy change of one mole of an ideal gas of vibrating diatomic molecules, as volume and temperature are changed, is given by; 7 AS = S(V;,T;) – S(V;, T;) = ;Rln + Rln T ii) The gas undergoes an isobaric compression from V; to V;/2. Evaluate the change in the number of microstates of the system that occurs as a result. ii) Using the equation derived in i), demonstrate that for an ideal gas undergoing an adiabatic expansion from initial volume V; to final volume V; the change in entropy is zero.

Answer 94 and 95

ANS COMPLETELY AND SURE

Refrigerant 134a enters an insulated diffuser as a saturated vapor at 80 deg F with a velocity of 800 ft/s. The inlet area is 1.4 in^2. At the exit, the pressure is 400 lbf/in2 and the velocity is negligible. The diffuser operates at steady state and potential energy effects can be neglected. Determine the mass flow rate, in lb/s, and the exit temperature, in deg F.

2. An ideal gas undergoes a process from state 1 ( T1= 300 K, P1= 100 kPa) to state 2 ( T2= 600 K, P2 500 kPa). The specific heats of the ideal gas are : c, = 1 kJ/kg-K and c, = 0.7 kJ/kg-K. The change in specific entropy of the ideal gas from state 1 to state 2 (in kJ/kg-K) is (correct to two decimal places).

One kg of an ideal gas (gas constant R = 287 J/kg.K) undergoes an irreversible process from state-1 (1 bar, 300 K) to state -2 (2 bar, 300 K). The change in specific entropy (52 - s1) of the gas (in J/kg. K) in the process is

Thermodynamics, please help and show all work please.

One-quarter lbmol of oxygen gas (O2) undergoes a process from p1 = 20 lbf/in2, T1 = 500oR to p2 = 150 lbf/in2. For the process W = -500 Btu and Q = -140.0 Btu. Assume the oxygen behaves as an ideal gas. Determine T2, in oR, and the change in entropy, in Btu/oR.

23 m³/hr of air at 600 kPa, 330 K enters a well-insulated, horizontal pipe having a diameter of 1.2 cm and exits at 120 kPa. Assume steady state and use the ideal gas model for the air. Also assume constant specific heat, c = 1.007 kJ/kg-K for air at 330K. Determine the mass flow rate, in kg/s, and the exit velocity, in m/s. Step 1 Determine the mass flow rate, in kg/s. m₁ = 0.04047 kg/s Step 2 Determine the exit velocity, in m/s. V₂ = 178.315 x m/s